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docs_md/articles/adem-brain_ed94b660-cf20-4ebb-8d6f-2b93505f2928.md

@@ -0,0 +1,529 @@
+---
+title: "ADEM, Brain"
+docid: "ed94b660-cf20-4ebb-8d6f-2b93505f2928"
+authors:
+  - key: "99e1aff7-f42c-43a0-95ae-d89c8551aa01"
+    value: "Kevin R. Moore, MD"
+breadcrumbs:
+  -
+    name: "Pediatrics"
+    slug: "pediatrics"
+    treeNodeId: "a915965c-d436-44cf-ae65-2f22e7246ea4"
+  -
+    name: "Diagnosis"
+    slug: "diagnosis"
+    treeNodeId: "2b5cea64-a083-489e-ac0c-ec14ba059026"
+  -
+    name: "Pediatric Neuroradiology"
+    slug: "pediatric-neuroradiology"
+    treeNodeId: "d0eb8f4a-e769-43dd-896c-8c9c27ce8759"
+  -
+    name: "Brain"
+    slug: "brain"
+    treeNodeId: "feaaadba-649b-4f0a-9aad-9188a8f9926a"
+  -
+    name: "Pathology-Based Diagnoses"
+    slug: "pathology-based-diagnoses"
+    treeNodeId: "2d26053f-23a7-4062-bf35-a93775ae1209"
+  -
+    name: "Inflammatory and Demyelinating Disease"
+    slug: "inflammatory-and-demyelinating-dis-"
+    treeNodeId: "cb319228-da96-4d29-8276-c72388a57656"
+  -
+    name: "ADEM, Brain"
+    slug: "adem-brain"
+    treeNodeId: null
+category: "Pediatrics"
+documentVersionId: "d15d7c30-1933-4a0f-afc7-3e9b13ce1ff7"
+imageCount: 26
+lastUpdated: "02/05/24"
+pageDescription: "ADEM, Brain"
+pageKeywords: "Pediatrics, Diagnosis, Pediatric Neuroradiology, Brain, Pathology-Based Diagnoses, Inflammatory and Demyelinating Disease, ADEM, Brain"
+pageTitle: "ADEM, Brain | STATdx"
+enhancedTitle: "ADEM, Brain"
+type: "DX"
+references: true
+breadcrumbs:
+  - "Pediatrics"
+  - "Diagnosis"
+  - "Pediatric Neuroradiology"
+  - "Brain"
+  - "Pathology-Based Diagnoses"
+  - "Inflammatory and Demyelinating Disease"
+  - "ADEM, Brain"
+---
+# KEY FACTS
+
+- ## Terminology
+  
+  
+    - Autoimmune-mediated white matter (WM) demyelination of brain &/or spinal cord, usually with remyelination
+- ## Imaging
+  
+  
+    - Best diagnostic clue: Multifocal WM and deep gray lesions days to weeks following infection/vaccination
+    - May involve both brain and spinal cord; WM > gray matter, but usually both affected
+    - Both supratentorial and infratentorial lesions
+    - Multifocal punctate to large, flocculent FLAIR hyperintensities
+          - Deep/juxtacortical WM > periventricular WM
+          - Do not usually involve callososeptal interface
+    - Most lesions show increased signal on DWI (T2 shine-through)
+    - Punctate, ring, incomplete ring, peripheral enhancement
+          - Absence of enhancement does not exclude diagnosis
+    - MRS: ↓ NAA within lesions; may see ↑ Cho, ↑ lactate
+- ## Top Differential Diagnoses
+  
+  
+    - Multiple sclerosis (MS)
+    - Collagen-vascular disorders
+    - Neoplasms
+    - Hemophagocytic lymphohistiocytosis (HLH)
+    - Mitochondrial diseases
+    - Leukodystrophies
+    - Acute hypertensive encephalopathy, PRES
+    - Autoimmune-mediated vasculitis
+    - Fabry disease
+- ## Pathology
+  
+  
+    - > 30 different infectious agents reported
+    - Anti-MOG IgG antibodies found more commonly in younger patients
+- ## Clinical Issues
+  
+  
+    - Mean age: 5-8 years but can occur at any age
+    - Male predominance (M:F = 1:0.6-0.8), unlike MS
+    - Usually monophasic, self-limited
+    - Complete recovery within 1 month: 50-60%
+    - Mortality: 10-30%
+- ## Diagnostic Checklist
+  
+  
+    - Imaging findings often lag behind symptom onset, resolution
+
+# TERMINOLOGY
+
+- ## Abbreviations
+  
+  
+    - Acute disseminated encephalomyelitis (ADEM)
+- ## Definitions
+  
+  
+    - Autoimmune-mediated white matter (WM) demyelination of brain &/or spinal cord, usually with remyelination
+
+# IMAGING
+
+- ## General Features
+  
+  
+    - ### Best diagnostic clue
+      
+      
+          - Multifocal WM/basal ganglia lesions days to weeks following preceding infection
+                  - 93% within 3 weeks of infection
+    - ### Location
+      
+      
+          - Widespread WM and gray matter brain abnormalities
+                  - Both supratentorial and infratentorial lesions
+                  - Most conspicuous on T2-weighted and fluid-attenuated inversion recovery (FLAIR) sequences
+          - May involve both brain and spinal cord; WM > gray matter, but usually both affected
+          - Deep/juxtacortical WM > periventricular WM
+    - ### Size
+      
+      
+          - Tumefactive lesions may be large but with less mass effect than expected from similar size tumor
+    - ### Morphology
+      
+      
+          - Punctate to flocculent
+          - Tumefactive, mass-like lesions possible
+- ## CT Findings
+  
+  
+    - ### NECT
+      
+      
+          - Initial CT normal in 40% of patients
+    - ### CECT
+      
+      
+          - Normal or multifocal punctate or ring-enhancing lesions
+- ## MR Findings
+  
+  
+    - ### T1WI
+      
+      
+          - Hypointense "black holes" uncommon
+    - ### T2WI
+      
+      
+          - Hyperintensities may be better visualized in brainstem and posterior fossa than on T2 FLAIR
+    - ### FLAIR
+      
+      
+          - Widespread multifocal punctate to large, flocculent FLAIR hyperintensities
+                  - Bilateral, asymmetric, frequently poorly marginated
+          - Involve peripheral WM-gray matter junction subcortical WM
+          - Thalami and basal ganglia symmetrically involved, particularly in children
+          - Can involve brainstem and posterior fossa
+          - Usually do **not** involve callososeptal interface
+    - ### DWI
+      
+      
+          - Variably hyperintense lesions on DWI (trace) images
+          - ADC may be increased or decreased
+                  - Most lesions show increased signal (T2 shine-through)
+                  - Diffusion restriction uncommon, suggests worse prognosis
+                  - Diffusivity normal within normal-appearing WM (NAWM), unlike MS
+    - ### T1WI C+
+      
+      
+          - Punctate, ring, incomplete ring, peripheral enhancement
+          - Cranial nerve(s) may enhance
+          - Absence of enhancement does not exclude ADEM
+    - ### MRS
+      
+      
+          - NAA low within lesions; lactate may be elevated
+          - Choline often elevated in acute lesions
+          - NAA normalizes with resolution of symptoms/MR abnormalities
+    - Magnetization transfer ratio (MTR)
+          - ADEM MTR normal within NAWM, unlike MS
+- ## Imaging Recommendations
+  
+  
+    - ### Best imaging tool
+      
+      
+          - Contrast-enhanced brain MR, including FLAIR T2 imaging
+                  - Initial imaging often normal but more sensitive than CT
+                  - May appear identical to MS; repeat MR necessary to distinguish with certainty
+- ## Nuclear Medicine Findings
+  
+  
+    - Tc-99m-HMPAO SPECT shows more extensive hypoperfusion than T2 lesions
+
+# DIFFERENTIAL DIAGNOSIS
+
+- [Multiple Sclerosis](/document/pediatric-multiple-sclerosis-brain/f2592b04-f800-4235-9eea-a43f2bf4adfe)
+    - Predilection for periventricular WM (callososeptal interface), subcortical U fibers, posterior fossa
+    - Lesions often more symmetric than ADEM
+    - Relapsing-remitting course common
+- ## Collagen-Vascular Disorders
+  
+  
+    - e.g., systemic lupus erythematosus (SLE), Sjögren syndrome, and neuro-Behçet disease
+    - Can present with primarily CNS involvement in children
+          - Imaging findings mimic ADEM
+    - Elevated markers of systemic inflammation help distinguish
+          - Abnormal antinuclear antibody profile, positive double-stranded DNA antibodies, elevated angiotensin converting enzyme, antiphospholipid antibodies
+    - Behcet: Classic triad of oral and genital ulcerations with uveitis
+- ## Neoplasms
+  
+  
+    - Mimic features of pediatric demyelinating processes
+    - Optic pathway neoplasms, primary brain tumors, intramedullary spinal cord tumors
+    - Specific imaging features and clinical history can help distinguish from pediatric demyelinating disorders
+- ## Hemophagocytic Lymphohistiocytosis
+  
+  
+    - With primary CNS involvement can (rarely) precede systemic disease manifestations
+    - Mimics clinical presentation of ADEM
+    - Imaging manifestations are protean
+- ## Mitochondrial Diseases
+  
+  
+    - MELAS and MERRF may present in setting of intercurrent acute infection
+    - Typical brain MR features include abnormal T2-hyperintense signal in basal ganglia and nonvascular distribution hemispheric lesions
+    - DWI MR will show acute restriction reflecting "metabolic stroke"
+          - Helps distinguish from nonrestricting demyelinating processes
+    - Elevation of serum, CSF lactate levels
+- [Leukodystrophies](/document/leukodystrophies/f4ff3738-131c-46bf-be71-1811f2c1776c)
+    - Genetic WM diseases are typically symmetrical, sometimes with characteristic location or appearance
+    - e.g., metachromatic leukodystrophy, X-linked adrenoleukodystrophy, Alexander disease, globoid cell leukodystrophy (Krabbe disease)
+- [Autoimmune-Mediated Vasculitis](/document/miscellaneous-vasculitis/5a4d4cbd-67e3-4722-8a44-8d411cbb98f0)
+    - Multifocal gray matter-WM lesions
+          - Bilateral, usually cortical/subcortical, basal ganglia/thalami
+          - Ring-enhancing lesions may mimic infection
+- [Acute Hypertensive Encephalopathy, PRES](/document/acute-hypertensive-encephalopathy--/efc6f9c2-dad9-4eb8-bad2-421bfaf1ec57)
+    - Typically posterior circulation in cortex/subcortical WM
+    - May affect deep gray nuclei
+- [Aging Brain With Hyperintense White Matter Lesions](/document/normal-aging-brain/2a315550-b2ea-4afe-a2ef-f93a2209f276)
+    - Atherosclerotic brain changes in 50% patients > 50 years old
+    - Found in normotensive patients; more common in hypertensives
+    - Present in 10-30% of cognitively normal older adult patients
+    - MR: Scattered, asymmetric WM lesions, without enhancement
+          - Often periatrial; posterior fossa uncommon
+          - Spares callososeptal interface, subcortical U fibers
+- [Fabry Disease](/document/fabry-disease/83fd222a-9b37-4087-afab-34ba74525887)
+    - Synonym: Angiokeratoma corporis diffusum universalis
+    - X-linked recessive; incidence 1/40,000
+    - Deficiency α-galactosidase A; overaccumulation of glycosphingolipids within lysosomes
+    - MR: Scattered, asymmetric WM lesions without enhancement
+          - May involve brainstem and posterior fossa
+          - Spares callososeptal interface and subcortical U fibers
+          - Cranial MR sensitive to identify neurologic involvement in asymptomatic patients
+    - Present with renal failure/heart disease
+
+# PATHOLOGY
+
+- ## General Features
+  
+  
+    - ### Etiology
+      
+      
+          - Autoimmune-mediated severe acute demyelination
+          - Pathogenesis incompletely understood, but thought to be triggered by environmental stimulus in genetically susceptible individuals
+                  - Myelin autoantigens, such as myelin basic protein (MBP), proteolipid protein (PLP), and myelin oligodendrocyte glycoprotein (MOG), share antigenic determinants with those of infecting pathogen
+          - Often follows antecedent nonspecific upper respiratory tract infection
+                  - > 30 different infectious agents and immunizations reported
+                  - Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2 or COVID) infection has been reported with ADEM, but overall incidence appears to be low
+                  - Some cases are spontaneous (no known cause)
+          - Neurologic symptoms typically appear 4-13 days after preceding infection
+          - Early reports suggested that minority of ADEM cases followed immunization
+          - Current studies show little or no association between ADEM and immunizations (postvaccinal ADEM)
+          - Implicated viral pathogens associated with ADEM are myriad and include coronavirus, coxsackievirus, cytomegalovirus, Epstein-Barr, herpes simplex, hepatitis A, HIV, influenza, measles, rubella, varicella zoster, and West Nile viruses
+          - Bacterial organisms associated with ADEM include *Borrelia burgdorferi*, *Chlamydia trachomatis*, *Leptospira*, *Mycoplasma pneumoniae*,*rickettsia*, and beta hemolytic *Streptococcus*
+    - ### Genetics
+      
+      
+          - ADEM associated with DRB1*01 and DRB1*017(03) in Russian population
+    - Acute hemorrhagic leukoencephalopathy variant associated with ulcerative colitis and asthma
+    - Anti-MOG IgG antibodies found more commonly in younger patients
+          - Most cases probably reflect MOGAD
+- ## Gross Pathologic & Surgical Features
+  
+  
+    - None, unless hemorrhage (rare) or tumefactive edema
+- ## Microscopic Features
+  
+  
+    - Acute myelin breakdown
+    - Perivenous inflammation; lymphocytic infiltrates
+    - Relative axonal preservation; atypical astrogliosis
+    - Virus particles generally not found, unlike viral encephalitides
+    - Similar to experimental allergic encephalomyelitis, supporting autoimmune-related etiology
+
+# CLINICAL ISSUES
+
+- ## Presentation
+  
+  
+    - ### Most common signs/symptoms
+      
+      
+          - Usually preceded by prodromal phase: Fever, malaise, myalgia
+          - Multifocal neurologic symptoms, 2 days to 4 weeks after viral illness
+                  - Initial symptoms: Headache, fever, drowsiness
+                  - Cranial nerve palsies, hemiparesis
+                  - Decreased consciousness (from lethargy to coma)
+                  - Behavioral changes
+    - ### Other signs/symptoms
+      
+      
+          - Seizures in 10-35%
+    - ### Clinical profile
+      
+      
+          - CSF normal in 60%
+          - If abnormal (lymphocyte pleocytosis, elevated protein) usually lacks CSF oligoclonal bands
+- ## Demographics
+  
+  
+    - ### Age
+      
+      
+          - Children > adults
+          - Mean age: 5-8 years but can occur at any age
+    - ### Sex
+      
+      
+          - Male predominance (M:F = 1.0:0.6-0.8), unlike MS
+    - ### Epidemiology
+      
+      
+          - Pediatric ADEM is uncommon illness
+                  - Estimated annual incidence 0.2-0.5 per 100,000 children
+          - Typically delay between symptom onset, imaging findings
+          - Rare, yet most common para-/postinfectious disorder
+          - Most common in winter and spring
+          - Exact epidemiology unknown but increasingly reported
+- ## Natural History & Prognosis
+  
+  
+    - Usually monophasic and self-limited
+    - Variable prognosis
+          - Complete recovery within 1 month (50-60%)
+          - Neurologic sequelae (most commonly seizures) (20-30%)
+          - Mortality (10-30%)
+          - Relapses are rare
+                  - "Relapsing disseminated encephalomyelitis"
+                  - Many of these cases may actually be MOG antibody disease (MOGAD)
+                  - May be difficult to distinguish from relapsing-remitting MS
+    - Varicella and rubella ADEM have preferential patterns
+          - Varicella ADEM characterized by cerebellar ataxia and mild pyramidal dysfunction
+          - Rubella ADEM characterized by acute explosive onset, seizures, coma, and moderate pyramidal signs
+    - Rare manifestations of ADEM
+          - Acute hemorrhagic leukoencephalopathy (2%)
+                  - Young patients with abrupt symptom onset and fulminant clinical course
+                  - Inflammatory hemorrhagic WM demyelination
+                  - These variants are more rapidly progressive and clinically severe than typical ADEM
+                            - Otherwise, their symptomatology is similar to typical ADEM with meningismus, headache, seizures, multifocal and asymmetric neurologic deficits, &/or coma
+                  - Prognosis for survival or recovery of neurologic function is worse than for classic ADEM
+          - Bilateral striatal necrosis (usually in infants, may be reversible)
+- ## Treatment
+  
+  
+    - Immunosuppressive/immunomodulatory therapy
+          - MR may show prompt improvement after therapy
+    - Plasma exchange therapy
+          - 40% of patients failing steroid treatment may show marked improvement
+
+# DIAGNOSTIC CHECKLIST
+
+- ## Image Interpretation Pearls
+  
+  
+    - Imaging findings often lag behind both symptom onset and resolution
+
+ 31576fd8-140b-43b2-9f58-b6f33ef20ca3
+
+## References
+
+# Selected References
+
+1. [Kalita IR et al: Acute abducens nerve palsy with acute disseminated encephalomyelitis-like presentation following COVID-19 vaccination. Indian J Ophthalmol. 71(5):2279-81, 2023](http://www.ncbi.nlm.nih.gov/pubmed/?term=37202971%5Bpmid%5D)
+1. [Chen LW et al: Prognostic factors for functional recovery in children with moderate to severe acute disseminated encephalomyelitis. Mult Scler Relat Disord. 66:104056, 2022](http://www.ncbi.nlm.nih.gov/pubmed/?term=35878513%5Bpmid%5D)
+1. [Wang Y et al: SARS-CoV-2-associated acute disseminated encephalomyelitis: a systematic review of the literature. J Neurol. 269(3):1071-92, 2022](http://www.ncbi.nlm.nih.gov/pubmed/?term=34459986%5Bpmid%5D)
+1. [Benallegue N et al: Neurological involvement in secondary hemophagocytic lymphohistiocytosis in children. Eur J Paediatr Neurol. 34:110-7, 2021](http://www.ncbi.nlm.nih.gov/pubmed/?term=34482125%5Bpmid%5D)
+1. [Pujari SS et al: Acute haemorrhagic leukoencephalitis (AHLE) - our experience and a short review. J Neuroimmunol. 361:577751, 2021](http://www.ncbi.nlm.nih.gov/pubmed/?term=34739912%5Bpmid%5D)
+1. [Baumann M et al: MRI of the first event in pediatric acquired demyelinating syndromes with antibodies to myelin oligodendrocyte glycoprotein. J Neurol. 265(4):845-55, 2018](http://www.ncbi.nlm.nih.gov/pubmed/?term=29423614%5Bpmid%5D)
+1. [Aubert-Broche B et al: Monophasic demyelination reduces brain growth in children. Neurology. 88(18):1744-50, 2017](http://www.ncbi.nlm.nih.gov/pubmed/?term=28381515%5Bpmid%5D)
+1. [Bester M et al: Neuroimaging of multiple sclerosis, acute disseminated encephalomyelitis, and other demyelinating diseases. Semin Roentgenol. 49(1):76-85, 2014](http://www.ncbi.nlm.nih.gov/pubmed/?term=24342677%5Bpmid%5D)
+1. [Longoni G et al: White matter changes in paediatric multiple sclerosis and monophasic demyelinating disorders. Brain. 140(5):1300-15, 2017](http://www.ncbi.nlm.nih.gov/pubmed/?term=28334875%5Bpmid%5D)
+1. [Koelman DLH et al: Acute disseminated encephalomyelitis: prognostic value of early follow-up brain MRI. J Neurol. 264(8):1754-62, 2017](http://www.ncbi.nlm.nih.gov/pubmed/?term=28695361%5Bpmid%5D)
+1. [Marziali S et al: Acute disseminated encephalomyelitis following Campylobacter jejuni gastroenteritis: Case report and review of the literature. Neuroradiol J. 30(1):65-70, 2017](http://www.ncbi.nlm.nih.gov/pubmed/?term=27888275%5Bpmid%5D)
+1. [Kanekar S et al: A pattern approach to focal white matter hyperintensities on magnetic resonance imaging. Radiol Clin North Am. 52(2):241-61, 2014](http://www.ncbi.nlm.nih.gov/pubmed/?term=24582339%5Bpmid%5D)
+1. [Daida K et al: Cytomegalovirus-associated encephalomyelitis in an immunocompetent adult: a two-stage attack of direct viral and delayed immune-mediated invasions. case report. BMC Neurol. 16(1):223, 2016](http://www.ncbi.nlm.nih.gov/pubmed/?term=27855658%5Bpmid%5D)
+1. [Pohl D et al: Acute disseminated encephalomyelitis: updates on an inflammatory CNS syndrome. Neurology. 87(9 Suppl 2):S38-45, 2016](http://www.ncbi.nlm.nih.gov/pubmed/?term=27572859%5Bpmid%5D)
+1. [Yuan JL et al: Acute disseminated encephalomyelitis following vaccination against hepatitis B in a child: a case report and literature review. Case Rep Neurol Med. 2016:2401809, 2016](http://www.ncbi.nlm.nih.gov/pubmed/?term=27478662%5Bpmid%5D)
+1. [Baumann M et al: Clinical and neuroradiological differences of paediatric acute disseminating encephalomyelitis with and without antibodies to the myelin oligodendrocyte glycoprotein. J Neurol Neurosurg Psychiatry. 86(3):265-72, 2015](http://www.ncbi.nlm.nih.gov/pubmed/?term=25121570%5Bpmid%5D)
+1. [Karussis D: The diagnosis of multiple sclerosis and the various related demyelinating syndromes: a critical review. J Autoimmun. 48-49:134-42, 2014](http://www.ncbi.nlm.nih.gov/pubmed/?term=24524923%5Bpmid%5D)
+1. [Mariotto S et al: Clinical spectrum and IgG subclass analysis of anti-myelin oligodendrocyte glycoprotein antibody-associated syndromes: a multicenter study. J Neurol. 264(12):2420-30, 2017](http://www.ncbi.nlm.nih.gov/pubmed/?term=29063242%5Bpmid%5D)
+1. [Nakamura Y et al: Anti-MOG antibody-positive ADEM following infectious mononucleosis due to a primary EBV infection: a case report. BMC Neurol. 17(1):76, 2017](http://www.ncbi.nlm.nih.gov/pubmed/?term=28420330%5Bpmid%5D)
+1. [Tenembaum SN: Acute disseminated encephalomyelitis. Handb Clin Neurol. 112:1253-62, 2013](http://www.ncbi.nlm.nih.gov/pubmed/?term=23622336%5Bpmid%5D)
+1. [Wingerchuk DM et al: Acute disseminated encephalomyelitis, transverse myelitis, and neuromyelitis optica. Continuum (Minneap Minn). 19(4 Multiple Sclerosis):944-67, 2013](http://www.ncbi.nlm.nih.gov/pubmed/?term=23917095%5Bpmid%5D)
+1. [Callen DJ et al: Role of MRI in the differentiation of ADEM from MS in children. Neurology. 72(11):968-73, 2009](http://www.ncbi.nlm.nih.gov/pubmed/?term=19038851%5Bpmid%5D)
+1. [Noorbakhsh F et al: Acute disseminated encephalomyelitis: clinical and pathogenesis features. Neurol Clin. 26(3):759-80, ix, 2008](http://www.ncbi.nlm.nih.gov/pubmed/?term=18657725%5Bpmid%5D)
+1. [Rossi A: Imaging of acute disseminated encephalomyelitis. Neuroimaging Clin N Am. 18(1):149-61; ix, 2008](http://www.ncbi.nlm.nih.gov/pubmed/?term=18319160%5Bpmid%5D)
+1. [Tenembaum S et al: Acute disseminated encephalomyelitis. Neurology. 68(16 Suppl 2):S23-36, 2007](http://www.ncbi.nlm.nih.gov/pubmed/?term=17438235%5Bpmid%5D)
+1. [Menge T et al: Acute disseminated encephalomyelitis: an update. Arch Neurol. 62(11):1673-80, 2005](http://www.ncbi.nlm.nih.gov/pubmed/?term=16286539%5Bpmid%5D)
+1. [Yeh EA et al: Detection of coronavirus in the central nervous system of a child with acute disseminated encephalomyelitis. Pediatrics. 113(1 Pt 1):e73-6, 2004](http://www.ncbi.nlm.nih.gov/pubmed/?term=14702500%5Bpmid%5D)
+1. [Dale RC: Acute disseminated encephalomyelitis. Semin Pediatr Infect Dis. 14(2):90-5, 2003](http://www.ncbi.nlm.nih.gov/pubmed/?term=12881796%5Bpmid%5D)
+1. [Garg RK: Acute disseminated encephalomyelitis. Postgrad Med J. 79(927):11-17, 2003](http://www.ncbi.nlm.nih.gov/pubmed/?term=12566545%5Bpmid%5D)
+1. [Idrissova ZhR et al: Acute disseminated encephalomyelitis in children: clinical features and HLA-DR linkage. Eur J Neurol. 10(5):537-46, 2003](http://www.ncbi.nlm.nih.gov/pubmed/?term=12940836%5Bpmid%5D)
+1. [Okamoto K et al: MR features of diseases involving bilateral middle cerebellar peduncles. AJNR Am J Neuroradiol. 24(10):1946-54, 2003](http://www.ncbi.nlm.nih.gov/pubmed/?term=14625215%5Bpmid%5D)
+1. [Sener RN: Neuro-Behcet's disease: diffusion MR imaging and proton MR spectroscopy. AJNR Am J Neuroradiol. 24(8):1612-4, 2003](http://www.ncbi.nlm.nih.gov/pubmed/?term=13679280%5Bpmid%5D)
+1. [Stonehouse M et al: Acute disseminated encephalomyelitis: recognition in the hands of general paediatricians. Arch Dis Child. 88(2):122-4, 2003](http://www.ncbi.nlm.nih.gov/pubmed/?term=12538312%5Bpmid%5D)
+1. [Inglese M et al: Magnetization transfer and diffusion tensor MR imaging of acute disseminated encephalomyelitis. AJNR Am J Neuroradiol. 23(2):267-72, 2002](http://www.ncbi.nlm.nih.gov/pubmed/?term=11847052%5Bpmid%5D)
+1. [Murthy JM: Acute disseminated encephalomyelitis. Neurol India. 50(3):238-43, 2002](http://www.ncbi.nlm.nih.gov/pubmed/?term=12391446%5Bpmid%5D)
+1. [Tenembaum S et al: Acute disseminated encephalomyelitis: a long-term follow-up study of 84 pediatric patients. Neurology. 59(8):1224-31, 2002](http://www.ncbi.nlm.nih.gov/pubmed/?term=12391351%5Bpmid%5D)
+1. [Bizzi A et al: Quantitative proton MR spectroscopic imaging in acute disseminated encephalomyelitis. AJNR Am J Neuroradiol. 22(6):1125-30, 2001](http://www.ncbi.nlm.nih.gov/pubmed/?term=11415908%5Bpmid%5D)
+1. [Honkaniemi J et al: Delayed MR imaging changes in acute disseminated encephalomyelitis. AJNR Am J Neuroradiol. 22(6):1117-24, 2001](http://www.ncbi.nlm.nih.gov/pubmed/?term=11415907%5Bpmid%5D)
+1. [Straussberg R et al: Improvement of atypical acute disseminated encephalomyelitis with steroids and intravenous immunoglobulins. Pediatr Neurol. 24(2):139-43, 2001](http://www.ncbi.nlm.nih.gov/pubmed/?term=11275464%5Bpmid%5D)
+1. [Dale RC et al: Acute disseminated encephalomyelitis, multiphasic disseminated encephalomyelitis and multiple sclerosis in children. Brain. 123 Pt 12:2407-22, 2000](http://www.ncbi.nlm.nih.gov/pubmed/?term=11099444%5Bpmid%5D)
+1. [Rust RS: Multiple sclerosis, acute disseminated encephalomyelitis, and related conditions. Semin Pediatr Neurol. 7(2):66-90, 2000](http://www.ncbi.nlm.nih.gov/pubmed/?term=10914409%5Bpmid%5D)
+1. [Schaefer PW et al: Diffusion-weighted MR imaging of the brain. Radiology. 217(2):331-45, 2000](http://www.ncbi.nlm.nih.gov/pubmed/?term=11058626%5Bpmid%5D)
+1. [Kocer N et al: CNS involvement in neuro-Behcet syndrome: an MR study. AJNR Am J Neuroradiol. 20(6):1015-24, 1999](http://www.ncbi.nlm.nih.gov/pubmed/?term=10445437%5Bpmid%5D)
+
+
+## Images
+
+
+### Selected Images
+
+![Axial FLAIR MR in a child with ADEM shows peripheral, confluent areas of hyperintensity predominantly involving subcortical white matter. Bilateral but asymmetric pattern is typical of ADEM.](images/app.statdx.com_image_thumbnail_0089d6c8-c46e-47c9-a72d-9b6ee9284d04_annotated_true_size_900_quality_90_69c8127b_20251018T152316Z.jpg)
+*Axial FLAIR MR in a child with ADEM shows peripheral, confluent areas of hyperintensity predominantly involving subcortical white matter. Bilateral but asymmetric pattern is typical of ADEM.*
+
+![Axial T1 C+ MR in the same patient shows marked, irregular enhancement of nearly all lesions. As ADEM is a monophasic illness, enhancement of most lesions is typical; all lesions have a similar time course. Enhancement of multiple sclerosis lesions is more variable.](images/app.statdx.com_image_thumbnail_64ffcf26-7ca7-4104-bfa4-b6548f582028_annotated_true_size_900_quality_90_04a7a3f4_20251018T152315Z.jpg)
+*Axial T1 C+ MR in the same patient shows marked, irregular enhancement of nearly all lesions. As ADEM is a monophasic illness, enhancement of most lesions is typical; all lesions have a similar time course. Enhancement of multiple sclerosis lesions is more variable.*
+
+![Axial FLAIR MR in a 5-year-old with ADEM following an EBV infection demonstrates more subtle findings with abnormal hyperintensity in the left basal ganglia <img src='/img/arrows/WS.png'/> and right parietal cortex/subcortical white matter <img src='/img/arrows/WO.png'/>.](images/app.statdx.com_image_thumbnail_903a6a28-4877-4eb7-801d-dee46bf162bd_annotated_true_size_900_quality_90_85ce8fb7_20251018T152316Z.jpg)
+*Axial FLAIR MR in a 5-year-old with ADEM following an EBV infection demonstrates more subtle findings with abnormal hyperintensity in the left basal ganglia <img src='/img/arrows/WS.png'/> and right parietal cortex/subcortical white matter <img src='/img/arrows/WO.png'/>.*
+
+![Axial T1 C+ MR in the same patient reveals no abnormal lesional contrast enhancement.](images/app.statdx.com_image_thumbnail_6ec7cb98-de90-4247-963e-31be1fa7ee52_annotated_true_size_900_quality_90_7360436d_20251018T152315Z.jpg)
+*Axial T1 C+ MR in the same patient reveals no abnormal lesional contrast enhancement.*
+
+![Axial T2 MR in a 21-month-old who presented with seizures and encephalopathy demonstrates numerous lesions involving both subcortical white matter and gray matter (caudate nuclei, left basal ganglia, both thalami).](images/app.statdx.com_image_thumbnail_fb52c1ce-8553-441d-a1cb-c49fe6580667_annotated_true_size_900_quality_90_dc29ce16_20251018T152316Z.jpg)
+*Axial T2 MR in a 21-month-old who presented with seizures and encephalopathy demonstrates numerous lesions involving both subcortical white matter and gray matter (caudate nuclei, left basal ganglia, both thalami).*
+
+![Coronal FLAIR MR in the same patient confirms characteristic lesion distribution. Contrast-enhanced imaging (not shown) demonstrated no lesional enhancement.](images/app.statdx.com_image_thumbnail_1e485e05-a9d9-4ec8-9ff1-359d53745e1c_annotated_true_size_900_quality_90_18d4794b_20251018T152315Z.jpg)
+*Coronal FLAIR MR in the same patient confirms characteristic lesion distribution. Contrast-enhanced imaging (not shown) demonstrated no lesional enhancement.*
+
+![Axial T2WI MR shows hyperintense lesions in the brachium pontis bilaterally, typical for demyelination. The right-sided lesion shows a targetoid <img src='/img/arrows/WS.png'/> appearance. Enhancement of several lesions was present on postcontrast T1 images (not shown).](images/app.statdx.com_image_thumbnail_18b81bfe-32d0-46ae-9261-89c5ac6de92e_annotated_true_size_900_quality_90_67a641ed_20251018T152316Z.jpg)
+*Axial T2WI MR shows hyperintense lesions in the brachium pontis bilaterally, typical for demyelination. The right-sided lesion shows a targetoid <img src='/img/arrows/WS.png'/> appearance. Enhancement of several lesions was present on postcontrast T1 images (not shown).*
+
+![Axial FLAIR MR shows large, confluent regions of hyperintense signal <img src='/img/arrows/CC.png'/> in the periventricular and subcortical white matter in a 14-year-old who presented with neck stiffness, fatigue, and seizures.](images/app.statdx.com_image_thumbnail_9d547a6a-7b9d-43b8-b2bf-3cb459f98fe8_annotated_true_size_900_quality_90_04b3f6ff_20251018T152315Z.jpg)
+*Axial FLAIR MR shows large, confluent regions of hyperintense signal <img src='/img/arrows/CC.png'/> in the periventricular and subcortical white matter in a 14-year-old who presented with neck stiffness, fatigue, and seizures.*
+
+![Axial SWI MR in the same patient shows petechial hemorrhages <img src='/img/arrows/CS.png'/> in regions of FLAIR signal abnormality.](images/app.statdx.com_image_thumbnail_c88bfbb2-5923-4952-8c80-65ac436e467b_annotated_true_size_900_quality_90_68ef6089_20251018T152316Z.jpg)
+*Axial SWI MR in the same patient shows petechial hemorrhages <img src='/img/arrows/CS.png'/> in regions of FLAIR signal abnormality.*
+
+![Sagittal T1 C+ MR in same patient shows extensive irregular ring enhancement <img src='/img/arrows/CC.png'/> involving multiple subcortical white matter lesions. Acute hemorrhagic leukoencephalopathy (AHL) is a rare manifestation of ADEM, occurring in 2% of cases. AHL is associated with a very poor prognosis. Aggressive therapeutic management is a prerequisite to avoid usual disease course with fatal outcome.](images/app.statdx.com_image_thumbnail_64cb6152-89e6-4027-b778-5d559cb3efeb_annotated_true_size_900_quality_90_a908aeb7_20251018T152321Z.jpg)
+*Sagittal T1 C+ MR in same patient shows extensive irregular ring enhancement <img src='/img/arrows/CC.png'/> involving multiple subcortical white matter lesions. Acute hemorrhagic leukoencephalopathy (AHL) is a rare manifestation of ADEM, occurring in 2% of cases. AHL is associated with a very poor prognosis. Aggressive therapeutic management is a prerequisite to avoid usual disease course with fatal outcome.*
+
+
+### Additional Images
+
+![Axial T1WI C+ MR shows an incomplete ring of peripheral enhancement, typical of a demyelinating process. Other contrast enhancement patterns include ovoid or punctate homogeneous enhancement.](images/app.statdx.com_image_thumbnail_1c49d689-a60d-45a3-8c9b-52aa69ea64be_annotated_true_size_900_quality_90_e7866374_20251018T152321Z.jpg)
+*Axial T1WI C+ MR shows an incomplete ring of peripheral enhancement, typical of a demyelinating process. Other contrast enhancement patterns include ovoid or punctate homogeneous enhancement.*
+
+![Axial DWI MR shows increased signal in areas of FLAIR hyperintensity (not shown).  The foci were hypointense on ADC images, indicating diffusion restriction. Both white matter and gray matter involvement is present. Diffusion restriction is an uncommon imaging finding and is associated with a worse prognosis.](images/app.statdx.com_image_thumbnail_68ac872b-ffc7-45df-944b-c92acff8b7cb_annotated_true_size_900_quality_90_bb79bfc6_20251018T152321Z.jpg)
+*Axial DWI MR shows increased signal in areas of FLAIR hyperintensity (not shown).  The foci were hypointense on ADC images, indicating diffusion restriction. Both white matter and gray matter involvement is present. Diffusion restriction is an uncommon imaging finding and is associated with a worse prognosis.*
+
+![Coronal T2WI MR shows large, confluent regions of hyperintense signal in the white matter <img src='/img/arrows/WO.png'/> and deep gray nuclei <img src='/img/arrows/WS.png'/> of a child with ADEM. Although ADEM predominantly involves white matter, gray matter is often affected.](images/app.statdx.com_image_thumbnail_4c698420-da7a-4ef8-a9a5-486dae2fb2ad_annotated_true_size_900_quality_90_b8fc7613_20251018T152322Z.jpg)
+*Coronal T2WI MR shows large, confluent regions of hyperintense signal in the white matter <img src='/img/arrows/WO.png'/> and deep gray nuclei <img src='/img/arrows/WS.png'/> of a child with ADEM. Although ADEM predominantly involves white matter, gray matter is often affected.*
+
+![MRS at long echo time (TE) in a patient with acute lesions in ADEM demonstrates an ↑ choline <img src='/img/arrows/CC.png'/>, ↓ NAA <img src='/img/arrows/CS.png'/>, and the presence of a lactate doublet <img src='/img/arrows/WS.png'/>. Increase in choline with corresponding reductions in NAA normalize as the clinical and conventional neuroimaging abnormalities resolve.](images/app.statdx.com_image_thumbnail_d84ff7a6-ae85-4c5d-b939-1711e1a097ef_annotated_true_size_900_quality_90_fdcfb7a4_20251018T152322Z.jpg)
+*MRS at long echo time (TE) in a patient with acute lesions in ADEM demonstrates an ↑ choline <img src='/img/arrows/CC.png'/>, ↓ NAA <img src='/img/arrows/CS.png'/>, and the presence of a lactate doublet <img src='/img/arrows/WS.png'/>. Increase in choline with corresponding reductions in NAA normalize as the clinical and conventional neuroimaging abnormalities resolve.*
+
+![Axial FLAIR MR shows bilateral, multiple asymmetric, flocculent, hyperintense lesions of ADEM.](images/app.statdx.com_image_thumbnail_ec8663a5-52f2-4149-8d68-5f8c603f1b79_annotated_true_size_900_quality_90_4d798e7a_20251018T152322Z.jpg)
+*Axial FLAIR MR shows bilateral, multiple asymmetric, flocculent, hyperintense lesions of ADEM.*
+
+![Coronal T1WI C+ MR demonstrates partial peripheral enhancement around multiple asymmetric flocculent lesions of acute disseminated encephalomyelitis. Note the supra- and infratentorial lesions.](images/app.statdx.com_image_thumbnail_4068f5f5-1f2b-4355-837a-8b17a894bdca_annotated_true_size_900_quality_90_24f28941_20251018T152323Z.jpg)
+*Coronal T1WI C+ MR demonstrates partial peripheral enhancement around multiple asymmetric flocculent lesions of acute disseminated encephalomyelitis. Note the supra- and infratentorial lesions.*
+
+![Axial FLAIR MR shows asymmetric, flocculent, nearly confluent, hyperintense lesions of ADEM within posterior fossa structures.](fed48635-3311-4ff4-ae2c-68e8330b75ed)
+*Axial FLAIR MR shows asymmetric, flocculent, nearly confluent, hyperintense lesions of ADEM within posterior fossa structures.*
+
+![Axial FLAIR MR reveals multiple  asymmetric, primarily punctate, hyperintense lesions of ADEM.](f35db971-737f-4cce-afba-e70659b67143)
+*Axial FLAIR MR reveals multiple  asymmetric, primarily punctate, hyperintense lesions of ADEM.*
+
+![Axial FLAIR MR demonstrates a large, tumefactive, hyperintense lesion. Less mass effect is present than expected for lesion size. Smaller lesions were also present at other locations.](afe5abf8-901e-47eb-90f1-68c8271cf4ab)
+*Axial FLAIR MR demonstrates a large, tumefactive, hyperintense lesion. Less mass effect is present than expected for lesion size. Smaller lesions were also present at other locations.*
+
+![Axial T1WI C+ MR in the same patient demonstrates a large, tumefactive, hypointense lesion with minimal partial peripheral enhancement. Less mass effect is present than expected for lesion size. More lesions were seen elsewhere.](1855f77d-0e73-47ea-a0c1-5db86dc083e7)
+*Axial T1WI C+ MR in the same patient demonstrates a large, tumefactive, hypointense lesion with minimal partial peripheral enhancement. Less mass effect is present than expected for lesion size. More lesions were seen elsewhere.*
+
+![Axial FLAIR MR demonstrates a rare manifestation of ADEM: Bilateral striatal necrosis, evidenced by asymmetric confluent hyperintensity involving the gray matter and white matter of bilateral corpus striatum.](5c6dc644-142a-4303-afb7-09c16c07363a)
+*Axial FLAIR MR demonstrates a rare manifestation of ADEM: Bilateral striatal necrosis, evidenced by asymmetric confluent hyperintensity involving the gray matter and white matter of bilateral corpus striatum.*
+
+![Axial DWI MR confirms the rare manifestation of ADEM, displaying bilateral striatal necrosis, as evidenced by asymmetric confluent restricted diffusion involving gray matter and white matter of bilateral corpus striatum.](f0e2bac7-bbc9-45da-8e3f-ddd9151ed43a)
+*Axial DWI MR confirms the rare manifestation of ADEM, displaying bilateral striatal necrosis, as evidenced by asymmetric confluent restricted diffusion involving gray matter and white matter of bilateral corpus striatum.*
+
+![Axial T2WI MR shows multiple bilateral but asymmetric, T2-hyperintense foci <img src='/img/arrows/WS.png'/>. None of the lesions demonstrates significant mass effect in this adult patient with ADEM. Imaging mimics multiple sclerosis, vasculitis, and microvascular ischemia.](36c82d94-ffcc-4bee-8ea6-91d4e8368bb8)
+*Axial T2WI MR shows multiple bilateral but asymmetric, T2-hyperintense foci <img src='/img/arrows/WS.png'/>. None of the lesions demonstrates significant mass effect in this adult patient with ADEM. Imaging mimics multiple sclerosis, vasculitis, and microvascular ischemia.*
+
+![Axial FLAIR MR shows a large, tumefactive, hyperintense ADEM lesion <img src='/img/arrows/WS.png'/> with mass effect less than expected for the size of the lesion. Another clue to its nonneoplastic nature is the right-sided lesion <img src='/img/arrows/WC.png'/>.](84bb9f5f-d05b-4391-bd16-8beea63e1fbb)
+*Axial FLAIR MR shows a large, tumefactive, hyperintense ADEM lesion <img src='/img/arrows/WS.png'/> with mass effect less than expected for the size of the lesion. Another clue to its nonneoplastic nature is the right-sided lesion <img src='/img/arrows/WC.png'/>.*
+
+![MRS at a long TE in the same patient shows the tumefactive lesion has a depressed choline <img src='/img/arrows/WC.png'/> and NAA <img src='/img/arrows/WO.png'/> metabolites in the presence of a large lactate doublet <img src='/img/arrows/WS.png'/>. This MRS helps distinguish this lesion from a neoplasm. MRS of ADEM may show elevated choline acutely.](8d4a240b-4ac5-4002-86f6-76f8dd742664)
+*MRS at a long TE in the same patient shows the tumefactive lesion has a depressed choline <img src='/img/arrows/WC.png'/> and NAA <img src='/img/arrows/WO.png'/> metabolites in the presence of a large lactate doublet <img src='/img/arrows/WS.png'/>. This MRS helps distinguish this lesion from a neoplasm. MRS of ADEM may show elevated choline acutely.*
+
+![Axial FLAIR MR shows typical findings of ADEM with peripheral, subcortical hyperintense foci <img src='/img/arrows/WC.png'/>. Bilateral insular involvement is seen <img src='/img/arrows/WS.png'/>. Periventricular and callososeptal lesions, which are typical of multiple sclerosis, are not commonly seen in ADEM.](261b8d47-c109-457f-b28e-2151acebd773)
+*Axial FLAIR MR shows typical findings of ADEM with peripheral, subcortical hyperintense foci <img src='/img/arrows/WC.png'/>. Bilateral insular involvement is seen <img src='/img/arrows/WS.png'/>. Periventricular and callososeptal lesions, which are typical of multiple sclerosis, are not commonly seen in ADEM.*
+

docs_md/articles/adem_a3fafeb7-5861-4364-beb8-c0e30220564e.md

@@ -403,57 +403,33 @@ breadcrumbs:
 
 ### Selected Images
 
-![Axial FLAIR MR shows peripheral, confluent areas of hyperintensity predominantly involving the subcortical white matter (WM) in this child with ADEM. The bilateral but asymmetric pattern is typical of ADEM.](images/app.statdx.com_image_deba3310-8e09-466c-97d2-1e6bccb28edf_dafbadc1_20251018T064947Z.jpg)
-*Axial FLAIR MR shows peripheral, confluent areas of hyperintensity predominantly involving the subcortical white matter (WM) in this child with ADEM. The bilateral but asymmetric pattern is typical of ADEM.*
-
 ![Axial FLAIR MR shows peripheral, confluent areas of hyperintensity predominantly involving the subcortical white matter (WM) in this child with ADEM. The bilateral but asymmetric pattern is typical of ADEM.](images/app.statdx.com_image_thumbnail_deba3310-8e09-466c-97d2-1e6bccb28edf_size_168_quality_85_3dfef960_20251018T064936Z.jpg)
 *Axial FLAIR MR shows peripheral, confluent areas of hyperintensity predominantly involving the subcortical white matter (WM) in this child with ADEM. The bilateral but asymmetric pattern is typical of ADEM.*
 
-![Axial T1 C+ MR in the same patient shows marked, irregular enhancement of nearly all lesions. As ADEM is a monophasic illness, enhancement of the majority of lesions is typical; all lesions have a similar time course. Enhancement of multiple sclerosis (MS) lesions is more variable.](images/app.statdx.com_image_e18458d3-5f6e-43fd-ab6d-72c7a86dca92_0f3893d6_20251018T064949Z.jpg)
+![Axial FLAIR MR shows peripheral, confluent areas of hyperintensity predominantly involving the subcortical white matter (WM) in this child with ADEM. The bilateral but asymmetric pattern is typical of ADEM.](images/app.statdx.com_image_thumbnail_deba3310-8e09-466c-97d2-1e6bccb28edf_size_174_quality_85_61e31a0b_20251018T152348Z.jpg)
-*Axial T1 C+ MR in the same patient shows marked, irregular enhancement of nearly all lesions. As ADEM is a monophasic illness, enhancement of the majority of lesions is typical; all lesions have a similar time course. Enhancement of multiple sclerosis (MS) lesions is more variable.*
+*Axial FLAIR MR shows peripheral, confluent areas of hyperintensity predominantly involving the subcortical white matter (WM) in this child with ADEM. The bilateral but asymmetric pattern is typical of ADEM.*
 
 ![Axial T1 C+ MR in the same patient shows marked, irregular enhancement of nearly all lesions. As ADEM is a monophasic illness, enhancement of the majority of lesions is typical; all lesions have a similar time course. Enhancement of multiple sclerosis (MS) lesions is more variable.](images/app.statdx.com_image_thumbnail_e18458d3-5f6e-43fd-ab6d-72c7a86dca92_size_168_quality_85_70272c40_20251018T064936Z.jpg)
 *Axial T1 C+ MR in the same patient shows marked, irregular enhancement of nearly all lesions. As ADEM is a monophasic illness, enhancement of the majority of lesions is typical; all lesions have a similar time course. Enhancement of multiple sclerosis (MS) lesions is more variable.*
 
-![Axial T1 C+ MR shows an incomplete ring of peripheral enhancement, typical of a demyelinating process. Other contrast enhancement patterns include ovoid or punctate homogeneous enhancement.](images/app.statdx.com_image_53135c0f-4c9e-4fb9-ab09-df46c5b40f70_c986514a_20251018T064950Z.jpg)
-*Axial T1 C+ MR shows an incomplete ring of peripheral enhancement, typical of a demyelinating process. Other contrast enhancement patterns include ovoid or punctate homogeneous enhancement.*
-
 ![Axial T1 C+ MR shows an incomplete ring of peripheral enhancement, typical of a demyelinating process. Other contrast enhancement patterns include ovoid or punctate homogeneous enhancement.](images/app.statdx.com_image_thumbnail_53135c0f-4c9e-4fb9-ab09-df46c5b40f70_size_168_quality_85_3f185a62_20251018T064936Z.jpg)
 *Axial T1 C+ MR shows an incomplete ring of peripheral enhancement, typical of a demyelinating process. Other contrast enhancement patterns include ovoid or punctate homogeneous enhancement.*
 
-![Axial DWI MR shows increased signal in areas of FLAIR hyperintensity. The foci were hypointense on ADC images, indicating diffusion restriction. Both WM and gray matter involvement is present. Diffusion restriction is an uncommon imaging finding and is associated with a worse prognosis.](images/app.statdx.com_image_b79995c4-6bff-49f1-af71-cb56fe4b4aa1_119a9c33_20251018T064951Z.jpg)
-*Axial DWI MR shows increased signal in areas of FLAIR hyperintensity. The foci were hypointense on ADC images, indicating diffusion restriction. Both WM and gray matter involvement is present. Diffusion restriction is an uncommon imaging finding and is associated with a worse prognosis.*
-
 ![Axial DWI MR shows increased signal in areas of FLAIR hyperintensity. The foci were hypointense on ADC images, indicating diffusion restriction. Both WM and gray matter involvement is present. Diffusion restriction is an uncommon imaging finding and is associated with a worse prognosis.](images/app.statdx.com_image_thumbnail_b79995c4-6bff-49f1-af71-cb56fe4b4aa1_size_168_quality_85_03275787_20251018T064936Z.jpg)
 *Axial DWI MR shows increased signal in areas of FLAIR hyperintensity. The foci were hypointense on ADC images, indicating diffusion restriction. Both WM and gray matter involvement is present. Diffusion restriction is an uncommon imaging finding and is associated with a worse prognosis.*
 
-![Axial T2 MR shows hyperintense lesions in the brachium pontis bilaterally, typical for demyelination. The right-sided lesion shows a targetoid <img src='/img/arrows/WS.png'/> appearance. Enhancement of several lesions was present on postcontrast T1 images (not shown).](images/app.statdx.com_image_f74d958e-f845-47e7-884e-331bf3dcb299_89b1781b_20251018T064952Z.jpg)
-*Axial T2 MR shows hyperintense lesions in the brachium pontis bilaterally, typical for demyelination. The right-sided lesion shows a targetoid <img src='/img/arrows/WS.png'/> appearance. Enhancement of several lesions was present on postcontrast T1 images (not shown).*
-
 ![Axial T2 MR shows hyperintense lesions in the brachium pontis bilaterally, typical for demyelination. The right-sided lesion shows a targetoid <img src='/img/arrows/WS.png'/> appearance. Enhancement of several lesions was present on postcontrast T1 images (not shown).](images/app.statdx.com_image_thumbnail_f74d958e-f845-47e7-884e-331bf3dcb299_size_168_quality_85_10b7c767_20251018T064936Z.jpg)
 *Axial T2 MR shows hyperintense lesions in the brachium pontis bilaterally, typical for demyelination. The right-sided lesion shows a targetoid <img src='/img/arrows/WS.png'/> appearance. Enhancement of several lesions was present on postcontrast T1 images (not shown).*
 
-![Axial FLAIR MR shows large, confluent regions of hyperintense signal <img src='/img/arrows/CC.png'/> in the periventricular and subcortical WM in a 14 year old who presented with neck stiffness, fatigue, and seizures.](images/app.statdx.com_image_3e8a9c1e-560e-4c5c-93bc-dda9b3773622_eda9eb67_20251018T064954Z.jpg)
-*Axial FLAIR MR shows large, confluent regions of hyperintense signal <img src='/img/arrows/CC.png'/> in the periventricular and subcortical WM in a 14 year old who presented with neck stiffness, fatigue, and seizures.*
-
 ![Axial FLAIR MR shows large, confluent regions of hyperintense signal <img src='/img/arrows/CC.png'/> in the periventricular and subcortical WM in a 14 year old who presented with neck stiffness, fatigue, and seizures.](images/app.statdx.com_image_thumbnail_3e8a9c1e-560e-4c5c-93bc-dda9b3773622_size_168_quality_85_caf40da9_20251018T064936Z.jpg)
 *Axial FLAIR MR shows large, confluent regions of hyperintense signal <img src='/img/arrows/CC.png'/> in the periventricular and subcortical WM in a 14 year old who presented with neck stiffness, fatigue, and seizures.*
 
-![Axial SWI MR in the same patient shows petechial hemorrhages <img src='/img/arrows/CS.png'/> in regions of FLAIR signal abnormality.](images/app.statdx.com_image_fa96c2d2-8153-44c2-bd76-be0296382093_e2505a5f_20251018T064955Z.jpg)
-*Axial SWI MR in the same patient shows petechial hemorrhages <img src='/img/arrows/CS.png'/> in regions of FLAIR signal abnormality.*
-
 ![Axial SWI MR in the same patient shows petechial hemorrhages <img src='/img/arrows/CS.png'/> in regions of FLAIR signal abnormality.](images/app.statdx.com_image_thumbnail_fa96c2d2-8153-44c2-bd76-be0296382093_size_168_quality_85_93dd4c72_20251018T064936Z.jpg)
 *Axial SWI MR in the same patient shows petechial hemorrhages <img src='/img/arrows/CS.png'/> in regions of FLAIR signal abnormality.*
 
-![Sagittal T1 C+ MR in the same patient shows extensive irregular ring enhancement <img src='/img/arrows/CC.png'/> in multiple subcortical WM lesions. Acute hemorrhagic leukoencephalopathy (AHL) is a rare manifestation of ADEM occurring in 2% of cases. AHL is associated with a very poor prognosis. Aggressive therapeutic management is a prerequisite to avoid usual disease course with fatal outcome.](images/app.statdx.com_image_b9452b6b-6772-4d91-8ca4-47ceaafa25f4_ddfedaec_20251018T064957Z.jpg)
-*Sagittal T1 C+ MR in the same patient shows extensive irregular ring enhancement <img src='/img/arrows/CC.png'/> in multiple subcortical WM lesions. Acute hemorrhagic leukoencephalopathy (AHL) is a rare manifestation of ADEM occurring in 2% of cases. AHL is associated with a very poor prognosis. Aggressive therapeutic management is a prerequisite to avoid usual disease course with fatal outcome.*
-
 ![Sagittal T1 C+ MR in the same patient shows extensive irregular ring enhancement <img src='/img/arrows/CC.png'/> in multiple subcortical WM lesions. Acute hemorrhagic leukoencephalopathy (AHL) is a rare manifestation of ADEM occurring in 2% of cases. AHL is associated with a very poor prognosis. Aggressive therapeutic management is a prerequisite to avoid usual disease course with fatal outcome.](images/app.statdx.com_image_thumbnail_b9452b6b-6772-4d91-8ca4-47ceaafa25f4_size_168_quality_85_3dcd4458_20251018T064936Z.jpg)
 *Sagittal T1 C+ MR in the same patient shows extensive irregular ring enhancement <img src='/img/arrows/CC.png'/> in multiple subcortical WM lesions. Acute hemorrhagic leukoencephalopathy (AHL) is a rare manifestation of ADEM occurring in 2% of cases. AHL is associated with a very poor prognosis. Aggressive therapeutic management is a prerequisite to avoid usual disease course with fatal outcome.*
 
-![Coronal T2 MR shows large, confluent regions of hyperintense signal in the WM  <img src='/img/arrows/WO.png'/> and deep gray nuclei <img src='/img/arrows/WS.png'/> of a child with ADEM. Although ADEM predominantly involves WM, gray matter is often affected.](images/app.statdx.com_image_113e918b-8d8f-46b8-8664-e0f617904251_b9bf7b86_20251018T064958Z.jpg)
-*Coronal T2 MR shows large, confluent regions of hyperintense signal in the WM  <img src='/img/arrows/WO.png'/> and deep gray nuclei <img src='/img/arrows/WS.png'/> of a child with ADEM. Although ADEM predominantly involves WM, gray matter is often affected.*
-
 ![Coronal T2 MR shows large, confluent regions of hyperintense signal in the WM  <img src='/img/arrows/WO.png'/> and deep gray nuclei <img src='/img/arrows/WS.png'/> of a child with ADEM. Although ADEM predominantly involves WM, gray matter is often affected.](images/app.statdx.com_image_thumbnail_113e918b-8d8f-46b8-8664-e0f617904251_size_168_quality_85_1b06d2b7_20251018T064936Z.jpg)
 *Coronal T2 MR shows large, confluent regions of hyperintense signal in the WM  <img src='/img/arrows/WO.png'/> and deep gray nuclei <img src='/img/arrows/WS.png'/> of a child with ADEM. Although ADEM predominantly involves WM, gray matter is often affected.*
 
@@ -466,15 +442,9 @@ breadcrumbs:
 
 ### Additional Images
 
-![Axial FLAIR MR shows multiple bilateral, asymmetric, flocculent, hyperintense lesions of acute disseminated encephalomyelitis.](images/app.statdx.com_image_bac2d338-fffe-48e4-be97-bb8258970076_425b9699_20251018T065002Z.jpg)
-*Axial FLAIR MR shows multiple bilateral, asymmetric, flocculent, hyperintense lesions of acute disseminated encephalomyelitis.*
-
 ![Axial FLAIR MR shows multiple bilateral, asymmetric, flocculent, hyperintense lesions of acute disseminated encephalomyelitis.](images/app.statdx.com_image_thumbnail_bac2d338-fffe-48e4-be97-bb8258970076_size_168_quality_85_4b79e54c_20251018T064936Z.jpg)
 *Axial FLAIR MR shows multiple bilateral, asymmetric, flocculent, hyperintense lesions of acute disseminated encephalomyelitis.*
 
-![Coronal T1 C+ MR demonstrates partial peripheral enhancement around multiple asymmetric, flocculent lesions of acute disseminated encephalomyelitis. Note the supra- and infratentorial lesions.](images/app.statdx.com_image_674fcfe9-2db8-4d36-a55c-9ca0a0672252_4fcbd413_20251018T065003Z.jpg)
-*Coronal T1 C+ MR demonstrates partial peripheral enhancement around multiple asymmetric, flocculent lesions of acute disseminated encephalomyelitis. Note the supra- and infratentorial lesions.*
-
 ![Coronal T1 C+ MR demonstrates partial peripheral enhancement around multiple asymmetric, flocculent lesions of acute disseminated encephalomyelitis. Note the supra- and infratentorial lesions.](images/app.statdx.com_image_thumbnail_674fcfe9-2db8-4d36-a55c-9ca0a0672252_size_168_quality_85_05b2865d_20251018T064936Z.jpg)
 *Coronal T1 C+ MR demonstrates partial peripheral enhancement around multiple asymmetric, flocculent lesions of acute disseminated encephalomyelitis. Note the supra- and infratentorial lesions.*
 

docs_md/articles/aqueductal-stenosis_6dfa6261-3945-4606-850b-51484d05e70c.md

@@ -0,0 +1,430 @@
+---
+title: "Aqueductal Stenosis"
+docid: "6dfa6261-3945-4606-850b-51484d05e70c"
+authors:
+  - key: "2c9d2e67-05db-4d26-b8cb-02e0f7566179"
+    value: "Usha D. Nagaraj, MD"
+  - key: "b2e6dabb-ee1c-42a4-a332-9f0814c1c607"
+    value: "Surjith Vattoth, MD, FRCR"
+breadcrumbs:
+  -
+    name: "Brain"
+    slug: "brain"
+    treeNodeId: "6d8829f1-14d7-45af-8675-255189aa526a"
+  -
+    name: "Diagnosis"
+    slug: "diagnosis"
+    treeNodeId: "51c00394-446e-4a38-94af-d3b1d14d34e8"
+  -
+    name: "Anatomy-Based Diagnoses"
+    slug: "anatomy-based-diagnoses"
+    treeNodeId: "529d3e33-f508-498c-bc70-cf962e81e629"
+  -
+    name: "Ventricles and Cisterns"
+    slug: "ventricles-and-cisterns"
+    treeNodeId: "33b267f0-908c-4c77-81f8-f6135d1bc592"
+  -
+    name: "Hydrocephalus"
+    slug: "hydrocephalus"
+    treeNodeId: "9ce86e3b-fab6-4657-9e51-5f47bb1a51b5"
+  -
+    name: "Aqueductal Stenosis"
+    slug: "aqueductal-stenosis"
+    treeNodeId: null
+category: "Brain"
+cmeTopicId: "22225b65-7fc8-4415-b55f-20fb85f6ecf5"
+documentVersionId: "f14f3356-bf6d-4b97-a2e5-77751c20492b"
+imageCount: 15
+lastUpdated: "07/16/20"
+pageDescription: "Aqueductal Stenosis"
+pageKeywords: "Brain, Diagnosis, Anatomy-Based Diagnoses, Ventricles and Cisterns, Hydrocephalus, Aqueductal Stenosis"
+pageTitle: "Aqueductal Stenosis | STATdx"
+enhancedTitle: "Aqueductal Stenosis"
+type: "DX"
+references: true
+breadcrumbs:
+  - "Brain"
+  - "Diagnosis"
+  - "Anatomy-Based Diagnoses"
+  - "Ventricles and Cisterns"
+  - "Hydrocephalus"
+  - "Aqueductal Stenosis"
+---
+# KEY FACTS
+
+- ## Terminology
+  
+  
+    - Aqueductal stenosis (AS)
+- ## Imaging
+  
+  
+    - Ventriculomegaly of lateral and 3rd ventricles with normal-sized 4th ventricle
+    - Obstruction of cerebral aqueduct ± tectal thickening
+    - Macrocephaly in fetus and infant
+    - Multiplanar MR with sagittal 3D True FISP/bFFE sequence to evaluate aqueduct
+- ## Top Differential Diagnoses
+  
+  
+    - Supratentorial volume loss
+    - Benign enlargement of subarachnoid fluid spaces of infancy
+    - Communicating hydrocephalus
+    - Secondary obstructive hydrocephalus
+- ## Pathology
+  
+  
+    - Congenital AS is common cause of fetal hydrocephalus
+    - Can be acquired (isolated) or associated with genetic disorder
+    - Subsets include stenosis from tectal thickening, obstructing web/gliotic tissue, or forking
+- ## Clinical Issues
+  
+  
+    - Though may present at any time from birth to adulthood, bimodal distribution in 1st year of life and adolescence
+    - Headache, papilledema, 6th nerve palsy, macrocephaly, bulging fontanelle
+    - C-section may be required for prenatally diagnosed cases due to macrocephaly
+- ## Diagnostic Checklist
+  
+  
+    - Look for coexisting brain anomalies, such as rhombencephalosynapsis or diencephalic-mesencephalic dysplasia
+
+# TERMINOLOGY
+
+- ## Abbreviations
+  
+  
+    - Aqueductal stenosis (AS)
+- ## Definitions
+  
+  
+    - Ventriculomegaly involving lateral and 3rd ventricles as result of complete or partial obstruction to CSF flow within cerebral aqueduct
+    - AS diagnosis generally refers to congenital form characterized by varying degree of obstruction at level of cerebral aqueduct
+          - However, tumors, germinal matrix hemorrhage, or vascular lesions can obstruct aqueduct as well
+
+# IMAGING
+
+- ## General Features
+  
+  
+    - ### Best diagnostic clue
+      
+      
+          - Ventriculomegaly of lateral and 3rd ventricles with normal-sized 4th ventricle
+          - Macrocephaly (typical of AS) can help differentiate from supratentorial volume loss (usually normal or decreased head circumference)
+    - ### Location
+      
+      
+          - Cerebral aqueduct
+                  - Most commonly at superior colliculi or intercollicular sulcus level
+    - ### Size
+      
+      
+          - Normal mean aqueductal cross-sectional area at birth is 0.2-1.8 mm²
+    - ### Morphology
+      
+      
+          - Funnel-shaped enlargement of proximal cerebral aqueduct or diffuse ↓ caliber of entire aqueduct
+- ## CT Findings
+  
+  
+    - ### NECT
+      
+      
+          - Ventriculomegaly of lateral and 3rd ventricles, normal-sized 4th ventricle
+          - ± periventricular interstitial edema from uncompensated hydrocephalus
+- ## MR Findings
+  
+  
+    - ### T1WI
+      
+      
+          - Ventriculomegaly of lateral and 3rd ventricles, foramina of Monro
+                  - Corpus callosum (CC) thinned, stretched upward
+                            - Often limits evaluation for coexisting callosal dysgenesis
+                  - ± lateral ventricular diverticulum (a.k.a. ventricular rupture or dehiscence)
+                  - Extraaxial CSF effacement
+                            - Limits ability to evaluate gyral-sulcal pattern
+          - Normal size of 4th ventricle, basilar foramina
+          - Aqueductal web: Thin tissue membrane separating dilated aqueduct from normal-sized 4th ventricle
+          - Look for coexisting brain anomalies, such as rhombencephalosynapsis or diencephalic-mesencephalic dysplasia (incomplete segmentation between diencephalon and mesencephalon)
+    - ### T2WI
+      
+      
+          - Presence of dephasing jet or flow void through aqueduct may suggest that AS is less likely, though does not completely exclude diagnosis
+          - ± periventricular interstitial edema
+          - Tectal plate thickening
+                  - Loss of differentiation between superior and inferior colliculi
+                  - May be difficult to differentiate from tectal plate glioma in certain cases
+                            - AS should **not** have T2-/FLAIR hyperintense signal or enhancement in tectal plate (tectum should be isointense to rest of midbrain on all pulse sequences)
+                            - Unlikely to be tectal plate glioma < 3 years of age
+          - Septum pellucidum often absent secondary to perforation
+    - ### T2* GRE
+      
+      
+          - May have trace amounts of blood products in aqueduct and ventricular system but no frank germinal matrix hemorrhage or other cause for bleeding
+    - ### T1WI C+
+      
+      
+          - Presence of tumor enhancement excludes congenital AS
+          - Hydrocephalus may induce leptomeningeal venous stasis → mimics meningitis or CSF metastases
+    - ### MRA
+      
+      
+          - Upward displacement of anterior cerebral artery branches secondary to hydrocephalus
+    - ### MRV
+      
+      
+          - Downward displacement of internal cerebral veins secondary to hydrocephalus
+    - ### MR cine
+      
+      
+          - Phase-contrast imaging may demonstrate absent or diminished CSF flow in aqueduct
+- ## Ultrasonographic Findings
+  
+  
+    - ### Grayscale ultrasound
+      
+      
+          - Ventriculomegaly of lateral and 3rd ventricles with normal-sized 4th ventricle in newborn with macrocephaly is highly suggestive of AS
+          - Obstetrical ultrasound may permit prenatal diagnosis
+                  - Usually severe lateral ventriculomegaly (> 15 mm)
+                  - Decreased transverse cerebellar diameter with coexisting rhombencephalosynapsis; fetal MR can help confirm
+                  - Adducted thumbs in male fetus raise possibility of X-linked hydrocephalus
+- ## Imaging Recommendations
+  
+  
+    - ### Best imaging tool
+      
+      
+          - Multiplanar MR with sagittal 3D True FISP/bFFE sequence to evaluate aqueduct
+
+# DIFFERENTIAL DIAGNOSIS
+
+- ## Supratentorial Volume Loss
+  
+  
+    - Should have normal or decreased head circumference
+- ## Benign Enlargement of Subarachnoid Spaces in Infancy
+  
+  
+    - a.k.a "benign macrocrania," thought to be mild form of communicating hydrocephalus from immaturity of CSF absorption mechanisms
+    - Patients have normal neurologic exam
+    - Ventricles are normal in size or mildly enlarged
+- ## Communicating Hydrocephalus
+  
+  
+    - Secondary to impaired absorption of CSF in subarachnoid spaces rather than anatomic obstruction
+    - Causes include meningitis, leptomeningeal metastatic disease, venous hypertension
+- ## Secondary Obstructive Hydrocephalus
+  
+  
+    - Cause of obstruction is extrinsic to aqueduct: Tumor, germinal matrix hemorrhage, vascular lesion, etc.
+
+# PATHOLOGY
+
+- ## General Features
+  
+  
+    - ### Etiology
+      
+      
+          - AS
+                  - Aqueductal lumen normally decreases in size beginning in 2nd month of fetal life and continuing until birth
+                            - Normal mean cross-sectional area of aqueduct is 0.5 mm² (range: 0.2-1.8 mm²)
+                            - Narrowing caused by growth pressures upon aqueduct from adjacent mesencephalic structures
+                  - AS pathologically obstructs CSF flow into 4th ventricle
+                  - CSF production in choroid plexus continues → lateral/3rd ventricular fluid ↑ pressure, ventriculomegaly
+                  - Ventricles expand, compress adjacent parenchyma, stretch CC
+                            - May rupture/open ependymal cell junctions → periventricular edema, ventricular diverticulum
+          - May be acquired or genetic
+                  - Isolated acquired forms from prior injury/insult, such as trace hemorrhage or infection, which results in webs or gliotic tissue obstructing aqueduct
+                  - Genetic forms often have other associated anomalies
+    - ### Genetics
+      
+      
+          - X-linked hydrocephalus
+                  - One of most common inherited causes of AS
+                  - Caused by mutation of *L1CAM*gene
+                            - Gene located on X chromosome (Xq28)
+                            - *L1CAM* expression is essential during normal embryonic development of nervous system
+                            - Codes for neural cell adhesion molecule transmembrane glycoprotein in immunoglobulin superfamily of cell adhesion molecules
+                            - Site of mutation within L1 protein correlates with disease severity
+                  - Patients have poor prognosis despite early shunting
+                  - Associated syndromes
+                            - MASA syndrome: **Mental disability**, **a**phasia, **s**huffling gait, and **a**dducted thumbs
+                            - CRASH syndrome: **C**allosal hypoplasia, mental disability, **a**dducted thumbs, **s**pastic paraplegia, and X-linked **h**ydrocephalus
+    - ### Associated abnormalities
+      
+      
+          - Rhombencephalosynapsis
+                  - Up to 65% of patients with rhombencephalosynapsis have coexisting AS
+          - CRASH syndrome
+                  - Absence/diminution of corticospinal tracts, thalamic fusion, collicular fusion, absence of septum pellucidum, CC dysgenesis
+                  - Thin cerebral mantle, malformations of cortical development, hypoplastic white matter
+          - Dystroglycanopathy (a.k.a. congenital muscular dystrophies, such as Walker-Warburg)
+                  - Usually associated with cerebellar dysplasia and abnormally small brainstem
+          - Chiari 2 malformation
+                  - Not well described, but coexisting AS suspected in cases with increased head circumference (majority of Chiari 2 patients have decreased head circumference)
+- ## Microscopic Features
+  
+  
+    - Can have associated malformations of cortical development with poor differentiation and maturation of cortical neurons on histology
+    - Aqueductal fork shows branching of aqueduct into dorsal and ventral channels
+          - Dorsal channel usually divided into several ductules
+          - These channels cannot be resolved on imaging due to microscopic size
+
+# CLINICAL ISSUES
+
+- ## Presentation
+  
+  
+    - ### Most common signs/symptoms
+      
+      
+          - Symptoms depend upon patient age at time of diagnosis
+          - Onset can be insidious, may occur from birth to adulthood though typically bimodal distribution
+    - ### Other signs/symptoms
+      
+      
+          - Headache, papilledema, 6th nerve palsy, bulging fontanelles
+          - Macrocrania, especially if sutures open
+          - Parinaud syndrome
+                  - Sun-setting eyes
+                  - Lid retraction
+                  - Tonic downgaze
+          - Bobble-head doll syndrome (rare)
+- ## Demographics
+  
+  
+    - ### Age
+      
+      
+          - Presentation, 2 peaks of distribution: 1 in 1st year of life (more common), other in adolescence
+    - ### Sex
+      
+      
+          - M:F = 2:1
+    - ### Epidemiology
+      
+      
+          - 0.5-1 per 1,000 births, recurrence rate of 1-4.5% in siblings
+          - AS responsible for ~ 20% of congenital hydrocephalus
+                  - Most common cause of prenatal obstructive hydrocephalus
+- ## Natural History & Prognosis
+  
+  
+    - Hydrocephalus usually progressive unless treated
+          - May stabilize as "arrested" or compensated hydrocephalus
+    - While isolated congenital AS has much better prognosis than AS with genetic disorder or other brain anomalies, only ~ 1/3 of patients with isolated AS have normal neurodevelopmental outcomes
+- ## Treatment
+  
+  
+    - CSF shunt diversion
+    - Endoscopic 3rd ventriculostomy
+    - Cerebral aqueductoplasty for membranous and short-segment aqueductal stenoses (selected cases)
+    - Prenatally diagnosed cases may require C-section due to macrocephaly
+
+# DIAGNOSTIC CHECKLIST
+
+- ## Consider
+  
+  
+    - Look for coexisting brain anomalies as they make difference in prognosis
+- ## Image Interpretation Pearls
+  
+  
+    - Use thin-section 3D True FISP/bFFE to better delineate aqueduct
+
+ 51b0f452-75a6-4416-baed-960891a1f404
+
+## References
+
+# Selected References
+
+1. [Guo D et al: A novel nonsense mutation in the L1CAM gene responsible for X-linked congenital hydrocephalus. J Gene Med. e3180, 2020](http://www.ncbi.nlm.nih.gov/pubmed/?term=32128973%5Bpmid%5D)
+1. [Alhousseini A et al: Familial hydrocephalus and dysgenesis of the corpus callosum associated with Xp22.33 duplication and stenosis of the aqueduct of sylvius with X-linked recessive inheritance pattern. Gynecol Obstet Invest. 84(4):412-6, 2019](http://www.ncbi.nlm.nih.gov/pubmed/?term=30965333%5Bpmid%5D)
+1. [Heaphy-Henault KJ et al: Congenital aqueductal stenosis: findings at fetal mri that accurately predict a postnatal diagnosis. AJNR Am J Neuroradiol. 39(5):942-9, 2018](http://www.ncbi.nlm.nih.gov/pubmed/?term=29519789%5Bpmid%5D)
+1. [Kline-Fath BM et al: Congenital aqueduct stenosis: progressive brain findings in utero to birth in the presence of severe hydrocephalus. Prenat Diagn. 38(9):706-12, 2018](http://www.ncbi.nlm.nih.gov/pubmed/?term=29927492%5Bpmid%5D)
+1. [Tonetti DA et al: Clinical outcomes of isolated congenital aqueductal stenosis. World Neurosurg. 114:e976-81, 2018](http://www.ncbi.nlm.nih.gov/pubmed/?term=29588243%5Bpmid%5D)
+1. [Yamada S et al: Current and emerging MR imaging techniques for the diagnosis and management of CSF flow disorders: a review of phase-contrast and time-spatial labeling inversion pulse. AJNR Am J Neuroradiol. 36(4):623-30, 2015](http://www.ncbi.nlm.nih.gov/pubmed/?term=25012672%5Bpmid%5D)
+1. [Griessenauer CJ et al: Pediatric tectal plate gliomas: clinical and radiological progression, MR imaging characteristics, and management of hydrocephalus. J Neurosurg Pediatr. 13(1):13-20, 2014](http://www.ncbi.nlm.nih.gov/pubmed/?term=24180680%5Bpmid%5D)
+1. [Kartal MG et al: Evaluation of hydrocephalus and other cerebrospinal fluid disorders with MRI: an update. Insights Imaging. 5(4):531-41, 2014](http://www.ncbi.nlm.nih.gov/pubmed/?term=24903254%5Bpmid%5D)
+1. [Tully HM et al: Infantile hydrocephalus: a review of epidemiology, classification and causes. Eur J Med Genet. 57(8):359-68, 2014](http://www.ncbi.nlm.nih.gov/pubmed/?term=24932902%5Bpmid%5D)
+1. [Ucar M et al: Evaluation of aqueductal patency in patients with hydrocephalus: three-dimensional high-sampling-efficiency technique (SPACE) versus two-dimensional turbo spin echo at 3 Tesla. Korean J Radiol. 15(6):827-35, 2014](http://www.ncbi.nlm.nih.gov/pubmed/?term=25469096%5Bpmid%5D)
+1. [Whitehead MT et al: Rhombencephalosynapsis as a cause of aqueductal stenosis: an under-recognized association in hydrocephalic children. Pediatr Radiol. 44(7):849-56, 2014](http://www.ncbi.nlm.nih.gov/pubmed/?term=24633306%5Bpmid%5D)
+1. [Muehlmann M et al: Magnetic resonance-based estimation of intracranial pressure correlates with ventriculoperitoneal shunt valve opening pressure setting in children with hydrocephalus. Invest Radiol. 48(7):543-7, 2013](http://www.ncbi.nlm.nih.gov/pubmed/?term=23695081%5Bpmid%5D)
+1. [O'Neill BR et al: Rapid sequence magnetic resonance imaging in the assessment of children with hydrocephalus. World Neurosurg. 80(6):e307-12, 2013](http://www.ncbi.nlm.nih.gov/pubmed/?term=23111234%5Bpmid%5D)
+1. [Rush ET et al: Four new patients with Gomez-Lopez-Hernandez syndrome and proposed diagnostic criteria. Am J Med Genet A. 161A(2):320-6, 2013](http://www.ncbi.nlm.nih.gov/pubmed/?term=23292994%5Bpmid%5D)
+1. [Gallo P et al: The endoscopic trans-fourth ventricle aqueductoplasty and stent placement for the treatment of trapped fourth ventricle: long-term results in a series of 18 consecutive patients. Neurol India. 60(3):271-7, 2012](http://www.ncbi.nlm.nih.gov/pubmed/?term=22824682%5Bpmid%5D)
+1. [Ishak GE et al: Rhombencephalosynapsis: a hindbrain malformation associated with incomplete separation of midbrain and forebrain, hydrocephalus and a broad spectrum of severity. Brain. 135(Pt 5):1370-86, 2012](http://www.ncbi.nlm.nih.gov/pubmed/?term=22451504%5Bpmid%5D)
+1. [Schroeder C et al: Why does endoscopic aqueductoplasty fail so frequently? Analysis of cerebrospinal fluid flow after endoscopic third ventriculostomy and aqueductoplasty using cine phase-contrast magnetic resonance imaging. J Neurosurg. 117(1):141-9, 2012](http://www.ncbi.nlm.nih.gov/pubmed/?term=-1%5Bpmid%5D)
+1. [Cinalli G et al: Hydrocephalus in aqueductal stenosis. Childs Nerv Syst. 27(10):1621-42, 2011](http://www.ncbi.nlm.nih.gov/pubmed/?term=21928028%5Bpmid%5D)
+1. [Algin O et al: Phase-contrast MRI and 3D-CISS versus contrast-enhanced MR cisternography on the evaluation of the aqueductal stenosis. Neuroradiology. 52(2):99-108, 2010](http://www.ncbi.nlm.nih.gov/pubmed/?term=19756563%5Bpmid%5D)
+1. [Stoquart-El Sankari S et al: Phase-contrast MR imaging support for the diagnosis of aqueductal stenosis. AJNR Am J Neuroradiol. 30(1):209-14, 2009](http://www.ncbi.nlm.nih.gov/pubmed/?term=18832663%5Bpmid%5D)
+1. [Bateman GA: Magnetic resonance imaging quantification of compliance and collateral flow in late-onset idiopathic aqueductal stenosis: venous pathophysiology revisited. J Neurosurg. 107(5):951-8, 2007](http://www.ncbi.nlm.nih.gov/pubmed/?term=17977266%5Bpmid%5D)
+1. [da Silva LR et al: Endoscopic aqueductoplasty in the treatment of aqueductal stenosis. Childs Nerv Syst. 23(11):1263-8, 2007](http://www.ncbi.nlm.nih.gov/pubmed/?term=17676325%5Bpmid%5D)
+1. [Koch-Wiewrodt D et al: Success and failure of endoscopic third ventriculostomy in young infants: are there different age distributions?. Childs Nerv Syst. 22(12):1537-41, 2006](http://www.ncbi.nlm.nih.gov/pubmed/?term=16944172%5Bpmid%5D)
+1. [Sansone JM et al: Endoscopic cerebral aqueductoplasty: a trans-fourth ventricle approach. J Neurosurg. 103(5 Suppl):388-92, 2005](http://www.ncbi.nlm.nih.gov/pubmed/?term=16302609%5Bpmid%5D)
+1. [Bhattacharyya KB et al: Bobble-head doll syndrome: some atypical features with a new lesion and review of the literature. Acta Neurol Scand. 108(3):216-20, 2003](http://www.ncbi.nlm.nih.gov/pubmed/?term=12911467%5Bpmid%5D)
+1. [Tisell M et al: Neurological symptoms and signs in adult aqueductal stenosis. Acta Neurol Scand. 107(5):311-7, 2003](http://www.ncbi.nlm.nih.gov/pubmed/?term=12713521%5Bpmid%5D)
+1. [Fukuhara T et al: Clinical features of late-onset idiopathic aqueductal stenosis. Surg Neurol. 55(3):132-6; discussion 136-7, 2001](http://www.ncbi.nlm.nih.gov/pubmed/?term=11311904%5Bpmid%5D)
+1. [Partington MD: Congenital hydrocephalus. Neurosurg Clin N Am. 12(4):737-42, ix, 2001](http://www.ncbi.nlm.nih.gov/pubmed/?term=11524294%5Bpmid%5D)
+1. [Schroeder HW et al: Endoscopic aqueductoplasty: technique and results. Neurosurgery. 45(3):508-15; discussion 515-8, 1999](http://www.ncbi.nlm.nih.gov/pubmed/?term=10493373%5Bpmid%5D)
+1. [Graf WD et al: The pachygyria-polymicrogyria spectrum of cortical dysplasia in X-linked hydrocephalus. Eur J Pediatr Surg. 8 Suppl 1:10-4, 1998](http://www.ncbi.nlm.nih.gov/pubmed/?term=9926316%5Bpmid%5D)
+1. [Castro-Gago M et al: Autosomal recessive hydrocephalus with aqueductal stenosis. Childs Nerv Syst. 12(4):188-91, 1996](http://www.ncbi.nlm.nih.gov/pubmed/?term=8739404%5Bpmid%5D)
+1. [Kadowaki C et al: Cine magnetic resonance imaging of aqueductal stenosis. Childs Nerv Syst. 11(2):107-11, 1995](http://www.ncbi.nlm.nih.gov/pubmed/?term=7758008%5Bpmid%5D)
+1. [Villani R et al: Long-term outcome in aqueductal stenosis. Childs Nerv Syst. 11(3):180-5, 1995](http://www.ncbi.nlm.nih.gov/pubmed/?term=7773981%5Bpmid%5D)
+
+
+## Images
+
+
+### Selected Images
+
+![Sagittal graphic shows obstructive hydrocephalus with markedly enlarged lateral and 3rd ventricles, a stretched (thinned) corpus callosum, and a funnel-shaped cerebral aqueduct <img src='/img/arrows/BS.png'/> related to distal obstruction. Note the normal size of the 4th ventricle and depression of the floor of the 3rd ventricle <img src='/img/arrows/BC.png'/> from the hydrocephalus.](images/app.statdx.com_image_thumbnail_b8037593-f2c6-448f-890c-33e3c832cfb8_annotated_true_size_900_quality_90_d08fbaed_20251018T165041Z.jpg)
+*Sagittal graphic shows obstructive hydrocephalus with markedly enlarged lateral and 3rd ventricles, a stretched (thinned) corpus callosum, and a funnel-shaped cerebral aqueduct <img src='/img/arrows/BS.png'/> related to distal obstruction. Note the normal size of the 4th ventricle and depression of the floor of the 3rd ventricle <img src='/img/arrows/BC.png'/> from the hydrocephalus.*
+
+![Sagittal T2WI from a fetal MR at 25 weeks gestational age with aqueductal stenosis shows macrocephaly, lateral and 3rd ventriculomegaly, and no CSF in the cerebral aqueduct <img src='/img/arrows/CS.png'/>.](images/app.statdx.com_image_thumbnail_cfcc833d-ed65-4463-8b21-0a16f998b61a_annotated_true_size_900_quality_90_0f9aeb64_20251018T165041Z.jpg)
+*Sagittal T2WI from a fetal MR at 25 weeks gestational age with aqueductal stenosis shows macrocephaly, lateral and 3rd ventriculomegaly, and no CSF in the cerebral aqueduct <img src='/img/arrows/CS.png'/>.*
+
+![Sagittal T1WI MR depicts proximal aqueductal stenosis <img src='/img/arrows/WS.png'/> producing enlargement of the lateral and 3rd ventricles with depression of the fornices <img src='/img/arrows/WC.png'/> in conjunction with normal 4th ventricle size. The tectum is dysplastic and thickened with collicular fusion <img src='/img/arrows/WO.png'/>.](images/app.statdx.com_image_thumbnail_691b95bc-abde-45e4-9c41-f468bff7e576_annotated_true_size_900_quality_90_5ca20c30_20251018T165041Z.jpg)
+*Sagittal T1WI MR depicts proximal aqueductal stenosis <img src='/img/arrows/WS.png'/> producing enlargement of the lateral and 3rd ventricles with depression of the fornices <img src='/img/arrows/WC.png'/> in conjunction with normal 4th ventricle size. The tectum is dysplastic and thickened with collicular fusion <img src='/img/arrows/WO.png'/>.*
+
+![Sagittal FIESTA of a 5 year old with aqueductal stenosis secondary to a small obstructing web <img src='/img/arrows/CS.png'/> is shown. This patient underwent a 3rd ventriculostomy <img src='/img/arrows/CC.png'/> and is doing well. There are no other brain anomalies.](images/app.statdx.com_image_thumbnail_7e7c9735-6651-40b7-92d2-9ba4c6ba4eb9_annotated_true_size_900_quality_90_58d84b56_20251018T165041Z.jpg)
+*Sagittal FIESTA of a 5 year old with aqueductal stenosis secondary to a small obstructing web <img src='/img/arrows/CS.png'/> is shown. This patient underwent a 3rd ventriculostomy <img src='/img/arrows/CC.png'/> and is doing well. There are no other brain anomalies.*
+
+![Sagittal T2WI MR of a 5 day old with prenatal diagnosis of aqueductal stenosis demonstrates effacement of the cerebral aqueduct <img src='/img/arrows/CS.png'/> with thickening of the tectum <img src='/img/arrows/CC.png'/>.](images/app.statdx.com_image_thumbnail_6e7dc665-e001-4483-982c-34742a8c9f88_annotated_true_size_900_quality_90_8dc210af_20251018T165041Z.jpg)
+*Sagittal T2WI MR of a 5 day old with prenatal diagnosis of aqueductal stenosis demonstrates effacement of the cerebral aqueduct <img src='/img/arrows/CS.png'/> with thickening of the tectum <img src='/img/arrows/CC.png'/>.*
+
+![Axial T1WI MR in the same patient demonstrates rhombencephalosynapsis <img src='/img/arrows/WS.png'/> and bilateral choanal atresia <img src='/img/arrows/BS.png'/>. Other anomalies in this patient included bilateral microphthalmia and tracheoesophageal fistula. This patient had a partial deletion of chromosome 3q and SOX2 gene mutation.](images/app.statdx.com_image_thumbnail_60101105-9030-4352-ac33-e49762486e93_annotated_true_size_900_quality_90_117f5060_20251018T165041Z.jpg)
+*Axial T1WI MR in the same patient demonstrates rhombencephalosynapsis <img src='/img/arrows/WS.png'/> and bilateral choanal atresia <img src='/img/arrows/BS.png'/>. Other anomalies in this patient included bilateral microphthalmia and tracheoesophageal fistula. This patient had a partial deletion of chromosome 3q and SOX2 gene mutation.*
+
+![Sagittal T1WI MR in a 2 day old with aqueductal stenosis with effacement of the aqueduct <img src='/img/arrows/CS.png'/> is shown. This patient also has diencephalic-mesencephalic dysplasia with incomplete separation of an enlarged massa intermedia from the midbrain <img src='/img/arrows/WO.png'/> with thickening of the 3rd ventricular floor <img src='/img/arrows/WS.png'/>.](images/app.statdx.com_image_thumbnail_7dec61fd-7d33-473d-a72a-826dbfe86d05_annotated_true_size_900_quality_90_6e98cdde_20251018T165041Z.jpg)
+*Sagittal T1WI MR in a 2 day old with aqueductal stenosis with effacement of the aqueduct <img src='/img/arrows/CS.png'/> is shown. This patient also has diencephalic-mesencephalic dysplasia with incomplete separation of an enlarged massa intermedia from the midbrain <img src='/img/arrows/WO.png'/> with thickening of the 3rd ventricular floor <img src='/img/arrows/WS.png'/>.*
+
+![Axial T2WI MR in the same patient demonstrates dilation of the lateral and 3rd ventricles with right ventricular diverticulum <img src='/img/arrows/CS.png'/> and multiple subependymal gray matter heterotopias <img src='/img/arrows/WS.png'/>.](images/app.statdx.com_image_thumbnail_89ddd8bc-0a66-4a10-ba6f-582e15706b98_annotated_true_size_900_quality_90_f90d73d0_20251018T165041Z.jpg)
+*Axial T2WI MR in the same patient demonstrates dilation of the lateral and 3rd ventricles with right ventricular diverticulum <img src='/img/arrows/CS.png'/> and multiple subependymal gray matter heterotopias <img src='/img/arrows/WS.png'/>.*
+
+![Sagittal T1WI MR in a patient with Walker-Warburg syndrome shows severe tectal dysgenesis <img src='/img/arrows/WS.png'/> with aqueductal occlusion. Marked enlargement of the lateral ventricles more than the 3rd ventricle is present. A &quot;zigzag&quot; brainstem and very small cerebellum are characteristic of this syndrome.](images/app.statdx.com_image_thumbnail_803672c1-c4ea-4b63-9503-c1496c7e60c7_annotated_true_size_900_quality_90_ad19ef8f_20251018T165041Z.jpg)
+*Sagittal T1WI MR in a patient with Walker-Warburg syndrome shows severe tectal dysgenesis <img src='/img/arrows/WS.png'/> with aqueductal occlusion. Marked enlargement of the lateral ventricles more than the 3rd ventricle is present. A &quot;zigzag&quot; brainstem and very small cerebellum are characteristic of this syndrome.*
+
+![Coronal T2WI MR in the same patient confirms marked ventriculomegaly, funnel-shaped cerebral aqueductal stenosis <img src='/img/arrows/WS.png'/>, fused fornices <img src='/img/arrows/BS.png'/>, and classic cobblestone lissencephaly.](images/app.statdx.com_image_thumbnail_3f80b454-0197-4bfd-a775-7b7c846e46a4_annotated_true_size_900_quality_90_9ac2b5aa_20251018T160013Z.jpg)
+*Coronal T2WI MR in the same patient confirms marked ventriculomegaly, funnel-shaped cerebral aqueductal stenosis <img src='/img/arrows/WS.png'/>, fused fornices <img src='/img/arrows/BS.png'/>, and classic cobblestone lissencephaly.*
+
+
+### Additional Images
+
+![Coronal T2WI MR of the same neonate, on the 1st day of life, shows marked ventriculomegaly with asymmetric bilateral subdural hygromas following spontaneous ventricular decompression into the bilateral subdural spaces. This patient also has the additional midline congenital anomaly of rhombencephalosynapsis with characteristic incomplete dentate gyrus separation <img src='/img/arrows/BS.png'/> correlating with clinical truncal ataxia.](images/app.statdx.com_image_thumbnail_8cd11d10-23ae-4a94-96b5-f990d00e6278_annotated_true_size_900_quality_90_0f7423b8_20251018T160013Z.jpg)
+*Coronal T2WI MR of the same neonate, on the 1st day of life, shows marked ventriculomegaly with asymmetric bilateral subdural hygromas following spontaneous ventricular decompression into the bilateral subdural spaces. This patient also has the additional midline congenital anomaly of rhombencephalosynapsis with characteristic incomplete dentate gyrus separation <img src='/img/arrows/BS.png'/> correlating with clinical truncal ataxia.*
+
+![Sagittal T2WI MR of a neonate with severe congenital hydrocephalus, imaged on the 1st day of life, shows severe aqueductal stenosis <img src='/img/arrows/CS.png'/> and abnormal dysplastic tectal thickening <img src='/img/arrows/CO.png'/>. Severe congenital hydrocephalus has resulted in spontaneous decompression into the subdural spaces <img src='/img/arrows/BS.png'/>.](images/app.statdx.com_image_thumbnail_0163a4f7-18e5-4811-8e10-7cbfc0576f14_annotated_true_size_900_quality_90_d4c7a9c8_20251018T160014Z.jpg)
+*Sagittal T2WI MR of a neonate with severe congenital hydrocephalus, imaged on the 1st day of life, shows severe aqueductal stenosis <img src='/img/arrows/CS.png'/> and abnormal dysplastic tectal thickening <img src='/img/arrows/CO.png'/>. Severe congenital hydrocephalus has resulted in spontaneous decompression into the subdural spaces <img src='/img/arrows/BS.png'/>.*
+
+![Coronal T2WI MR shows &quot;funneling&quot; of the aqueduct in the coronal plane <img src='/img/arrows/CS.png'/>, with a markedly distended ventricular system proximal to the stenotic aqueduct.](e30bbdfe-503f-454d-a570-d0d071adf442)
+*Coronal T2WI MR shows &quot;funneling&quot; of the aqueduct in the coronal plane <img src='/img/arrows/CS.png'/>, with a markedly distended ventricular system proximal to the stenotic aqueduct.*
+
+![Sagittal T2WI MR shows massively distended 3rd and lateral ventricles with distal aqueductal stenosis <img src='/img/arrows/BS.png'/>. Note the severe stretching of the corpus callosum <img src='/img/arrows/BO.png'/> and depression of the fornices <img src='/img/arrows/BC.png'/>.](39652cf8-1cab-4160-a593-4f0796871390)
+*Sagittal T2WI MR shows massively distended 3rd and lateral ventricles with distal aqueductal stenosis <img src='/img/arrows/BS.png'/>. Note the severe stretching of the corpus callosum <img src='/img/arrows/BO.png'/> and depression of the fornices <img src='/img/arrows/BC.png'/>.*
+
+![Sagittal T2WI MR reveals distal aqueductal stenosis with an enlarged, funnel-shaped cerebral aqueduct <img src='/img/arrows/CS.png'/> and mild abnormal tectal thickening. Note the lateral and 3rd ventriculomegaly with normal size of the 4th ventricle.](891e5fdf-9bb6-4085-b168-4e5738367176)
+*Sagittal T2WI MR reveals distal aqueductal stenosis with an enlarged, funnel-shaped cerebral aqueduct <img src='/img/arrows/CS.png'/> and mild abnormal tectal thickening. Note the lateral and 3rd ventriculomegaly with normal size of the 4th ventricle.*
+

docs_md/articles/asymmetric-lateral-ventricles_87387f0d-9b20-4288-a250-aa3ec83520c4.md

@@ -0,0 +1,413 @@
+---
+title: "Asymmetric Lateral Ventricles"
+docid: "87387f0d-9b20-4288-a250-aa3ec83520c4"
+authors:
+  - key: "1fa14dfd-71ea-4960-908e-e720313bc63a"
+    value: "Santhosh Gaddikeri, MD"
+  - key: "30ce27b2-237f-4aff-a88f-65ead356335b"
+    value: "Marinos Kontzialis, MD"
+breadcrumbs:
+  -
+    name: "Brain"
+    slug: "brain"
+    treeNodeId: "6d8829f1-14d7-45af-8675-255189aa526a"
+  -
+    name: "Differential Diagnosis"
+    slug: "differential-diagnosis"
+    treeNodeId: "a7fdd139-664e-4bb8-8d18-400e4733ff60"
+  -
+    name: "Ventricles, Periventricular Regions"
+    slug: "ventricles-periventricular-regions"
+    treeNodeId: "353c434a-a6fc-4ef1-8786-d30a1988a4dc"
+  -
+    name: "Generic Imaging Patterns"
+    slug: "generic-imaging-patterns"
+    treeNodeId: "969c31a2-ef56-4fc3-9125-05857cf9aac3"
+  -
+    name: "Asymmetric Lateral Ventricles"
+    slug: "asymmetric-lateral-ventricles"
+    treeNodeId: null
+category: "Brain"
+cmeTopicId: "5536eb32-54f9-4eb3-83c6-15950dc4efe6"
+documentVersionId: "7b24399c-3ad6-47c3-9521-b6125b27d26d"
+imageCount: 54
+lastUpdated: "01/25/23"
+pageDescription: "Asymmetric Lateral Ventricles"
+pageKeywords: "Brain, Differential Diagnosis, Ventricles, Periventricular Regions, Generic Imaging Patterns, Asymmetric Lateral Ventricles"
+pageTitle: "Asymmetric Lateral Ventricles | STATdx"
+enhancedTitle: "Asymmetric Lateral Ventricles"
+type: "DDX"
+references: true
+breadcrumbs:
+  - "Brain"
+  - "Differential Diagnosis"
+  - "Ventricles, Periventricular Regions"
+  - "Generic Imaging Patterns"
+  - "Asymmetric Lateral Ventricles"
+---
+# ESSENTIAL INFORMATION
+
+- ## Key Differential Diagnosis Issues
+  
+  
+    - Asymmetric lateral ventricles are most commonly seen as normal variant
+- ## Helpful Clues for Common Diagnoses
+  
+  
+    - **Normal Variant**
+          - Asymmetric lateral ventricles seen in 5-10% of normal population
+          - Asymmetry mild to moderate, left > right
+          - Septum may be displaced across midline
+          - No associated mass effect, herniation, or parenchymal atrophy
+          - Must exclude parenchymal or intraventricular abnormality
+    - **Extrinsic Mass Effect**
+          - Etiologies include mass, hemorrhage, infarct, infection
+          - Mass can cause ventricular deformity, subfalcine herniation
+    - **Encephalomalacia, General**
+          - Parenchymal loss results in compensatory ventricular enlargement
+          - Common etiologies include chronic infarct, trauma, surgery
+    - **Intraventricular Hemorrhage**
+          - Involved ventricle may dilate early from mass effect
+          - Chronic dilation may be due to scarring and adhesions
+          - Etiologies include trauma, arteriovenous malformation (AVM), basal ganglia hemorrhage
+    - **Herniation Syndromes, Intracranial**
+          - Subfalcine herniation: Cingulate gyrus herniates under falx
+                  - Ipsilateral lateral ventricle compressed
+                  - Foramen of Monro obstructs and causes contralateral lateral ventricle enlargement
+          - Unilateral descending transtentorial herniation (uncal): Herniation of medial temporal lobe inferiorly
+                  - Contralateral temporal horn becomes entrapped and enlarges
+          - Entrapped ventricle: Typically temporal horn, by extrinsic mass effect
+    - **Surgical Defects**
+          - Look for calvarial defect or "tract"
+          - Typically related to resection of mass
+          - Ventricle enlarged unilateral to defect
+    - **Obstructive Hydrocephalus**
+          - Typically acquired and bilateral
+          - May be unilateral if shunt complication or obstructing tumor is cause
+          - Rare: Colloid cyst may obstruct unilateral foramen of Monro and cause unilateral ventriculomegaly
+    - **Choroid Plexus Cyst**
+          - a.k.a. choroid plexus xanthogranuloma
+          - Most common choroid plexus mass in adults
+          - Nonneoplastic, noninflammatory cyst of choroid plexus
+          - Common incidental finding in older patients (40% prevalence)
+          - Typically bilateral; may be unilateral and enlarge lateral ventricle
+          - Most in lateral ventricular atria
+          - 60-80% bright on DWI
+- ## Helpful Clues for Less Common Diagnoses
+  
+  
+    - **Ventriculitis**
+          - Ventriculomegaly with debris level, enhancing ependyma, periventricular T2/FLAIR hyperintensities
+          - May affect lateral ventricles asymmetrically, particularly if related to shunt placement or abscess rupture
+          - Restricted diffusion of layering debris is characteristic
+          - Bacterial ventriculitis may occur in healthy individuals after trauma or neurosurgical procedure
+          - Fungal or viral ventriculitis occurs most commonly in immunosuppressed patients
+    - **CSF Shunts and Complications**
+          - Common complications include shunt obstruction or breakage, infection, overdrainage
+          - Asymmetric ventricles may result from overdrainage or underdrainage of "isolated" ventricle
+    - **Meningioma**
+          - Although rare, still one of more common intraventricular neoplasms in adults
+          - More common in females (F:M = 2:1)
+          - Most common location is ventricular atrium with slight majority on left
+          - Smooth, avidly enhancing intraventricular mass
+          - 50% calcified; cystic changes may be present
+    - **Choroid Plexus Papilloma**
+          - Enhancing, lobulated intraventricular mass in child
+          - 50% in lateral ventricle atrium, left > right
+          - 40% in 4th ventricle
+          - Increased CSF production in most cases, CSF obstruction in some cases
+          - May have CSF spread of tumor
+    - **Neurocytoma, Central**
+          - Neurocytoma arising from ventricular system, usually septum pellucidum or lateral ventricle
+          - Well-circumscribed, lobulated, "bubbly" lesions
+          - 50% calcifications, cyst-like areas, enhancement, prominent associated flow voids
+          - MRS: Glycine peak (3.55 ppm) may help differentiation from other intraventricular neoplasms
+    - **Neurocysticercosis**
+          - May involve cisterns > parenchyma > ventricles
+          - Intraventricular disease anywhere from 0.7-33% of cases
+          - May lead to obstructive hydrocephalus, ventriculitis, adhesions
+          - Intraventricular cyst signal intensity may differ slightly from CSF on T1, T2, FLAIR
+- ## Helpful Clues for Rare Diagnoses
+  
+  
+    - **Intraventricular Synechiae/Adhesions**
+          - May be congenital or acquired (prior bleed, infection, tumor)
+          - Look for enhancing septa, intraventricular cysts within ventricle
+    - **Choroid Plexus Carcinoma**
+          - Enhancing intraventricular mass and ependymal invasion in young child
+          - CSF seeding common
+          - Imaging does not allow reliable distinction between choroid plexus papilloma and carcinoma
+          - May be more heterogeneous than choroid plexus papilloma in part reflecting areas of necrosis
+          - May demonstrate elevation of lactate level
+    - **Ependymal Cyst**
+          - Nonenhancing, thin-walled cyst with CSF density/intensity
+          - Lateral ventricle most common location
+          - Most are incidental
+          - Best diagnostic clue: Nonenhancing, thin-walled CSF density/intensity cyst in lateral ventricle
+    - **Dyke-Davidoff-Masson**
+          - Antenatal unilateral hemispheric insult causes cerebral hemiatrophy
+          - Compensatory ipsilateral calvarial thickening, hyperpneumatized frontal sinuses and temporal bones due to longstanding cerebral hemiatrophy
+          - Dilated ventricle from volume loss is ipsilateral to small hemisphere
+    - **Hemimegalencephaly**
+          - Unilateral hemispheric cortical thickening
+          - Dilated, usually dysmorphic ventricle ipsilateral to enlarged hemisphere
+          - Ipsilateral extracalvarial soft tissues may be larger
+          - Pachygyria, polymicrogyria, heterotopias, abnormal white matter signal, blurring of gray-white matter junction
+    - **Rasmussen Encephalitis**
+          - Chronic unilateral brain inflammation of uncertain etiology leading to progressive hemispheric atrophy
+          - Early focal swelling of gyri
+          - Unilateral, predominantly frontoinsular cortical and subcortical T2/FLAIR hyperintensity progress to atrophy
+- ## Other Essential Information
+  
+  
+    - High-resolution MR cisternography: CISS, balanced FFE, FIESTA
+          - May detect small septations or arachnoid membranes causing obstruction
+    - Cine CSF flow study may help detect physiologic flow obstruction from arachnoid webs or membranes
+          - May assess adequacy of drainage procedures
+
+## References
+
+# Selected References
+
+1. [Balasubramaniam C: Shunt complications - staying out of trouble. Neurol India. 69(Supplement):S495-501, 2021](http://www.ncbi.nlm.nih.gov/pubmed/?term=35103008%5Bpmid%5D)
+1. [Lanska DJ: Cruveilhier's unrecognized case (c1831) of Dyke-Davidoff-Masson syndrome. Eur Neurol. 84(4):300-6, 2021](http://www.ncbi.nlm.nih.gov/pubmed/?term=33965957%5Bpmid%5D)
+1. [Cay-Martinez KC et al: Rasmussen encephalitis: an update. Semin Neurol. 40(2):201-10, 2020](http://www.ncbi.nlm.nih.gov/pubmed/?term=32185790%5Bpmid%5D)
+1. [Crawford JR et al: Perinatal (fetal and neonatal) choroid plexus tumors: a review. Childs Nerv Syst. 35(6):937-44, 2019](http://www.ncbi.nlm.nih.gov/pubmed/?term=30953158%5Bpmid%5D)
+1. [Tan LA et al: Obstructive hydrocephalus due to intraventricular hemorrhage after incidental durotomy during lumbar spine surgery. Spine (Phila Pa 1976). 43(5):E316-9, 2018](http://www.ncbi.nlm.nih.gov/pubmed/?term=26208226%5Bpmid%5D)
+1. [Zamora CA et al: Teaching neuroImages: Dyke-Davidoff-Masson in Sturge-Weber syndrome. Neurology. 85(16):e128, 2015](http://www.ncbi.nlm.nih.gov/pubmed/?term=26481933%5Bpmid%5D)
+1. [Smith AB et al: From the radiologic pathology archives: intraventricular neoplasms: radiologic-pathologic correlation. Radiographics. 33(1):21-43, 2013](http://www.ncbi.nlm.nih.gov/pubmed/?term=23322825%5Bpmid%5D)
+1. [Kimura-Hayama ET et al: Neurocysticercosis: radiologic-pathologic correlation. Radiographics. 30(6):1705-19, 2010](http://www.ncbi.nlm.nih.gov/pubmed/?term=21071384%5Bpmid%5D)
+1. [Kiroğlu Y et al: Cerebral lateral ventricular asymmetry on CT: how much asymmetry is representing pathology? Surg Radiol Anat. 30(3):249-55, 2008](http://www.ncbi.nlm.nih.gov/pubmed/?term=18253688%5Bpmid%5D)
+1. [Rastogi S et al: Neuroimaging in pediatric epilepsy: a multimodality approach. Radiographics. 28(4):1079-95, 2008](http://www.ncbi.nlm.nih.gov/pubmed/?term=18635630%5Bpmid%5D)
+1. [Osborn AG, Preece MT. Intracranial cysts: radiologic-pathologic correlation and imaging approach. Radiology. 2006 Jun;239(3):650-64.](http://www.ncbi.nlm.nih.gov/pubmed/?term=16714456%5Bpmid%5D)
+1. [Koeller KK et al: Cerebral intraventricular neoplasms: radiologic-pathologic correlation. Radiographics. 22(6):1473-505, 2002](http://www.ncbi.nlm.nih.gov/pubmed/?term=12432118%5Bpmid%5D)
+
+
+## Images
+
+
+### Selected Images
+
+![Axial T2 MR demonstrates normal variant anatomy with mild asymmetric prominence of the right lateral ventricle <img src='/img/arrows/CO.png'/> when compared to the left. Note the septum is slightly deviated to the left <img src='/img/arrows/CS.png'/>.](images/app.statdx.com_image_thumbnail_74e87ea4-3c2a-400b-b714-f9fa2db4e66a_annotated_true_size_900_quality_90_2466c18c_20251018T165124Z.jpg)
+**Normal Variant**
+*Axial T2 MR demonstrates normal variant anatomy with mild asymmetric prominence of the right lateral ventricle <img src='/img/arrows/CO.png'/> when compared to the left. Note the septum is slightly deviated to the left <img src='/img/arrows/CS.png'/>.*
+
+![Axial T2 MR demonstrates normal variant anatomy with mild asymmetric prominence of the right lateral ventricle <img src='/img/arrows/CO.png'/> when compared to the left. Note the septum is slightly deviated to the left <img src='/img/arrows/CS.png'/>.](images/app.statdx.com_image_thumbnail_74e87ea4-3c2a-400b-b714-f9fa2db4e66a_size_174_quality_85_592b5076_20251018T165117Z.jpg)
+**Normal Variant**
+*Axial T2 MR demonstrates normal variant anatomy with mild asymmetric prominence of the right lateral ventricle <img src='/img/arrows/CO.png'/> when compared to the left. Note the septum is slightly deviated to the left <img src='/img/arrows/CS.png'/>.*
+
+![Axial FLAIR MR demonstrates a large,  heterogeneous mass in the left frontal lobe <img src='/img/arrows/CS.png'/> with surrounding edema and mass effect with compression of the left lateral ventricle <img src='/img/arrows/CO.png'/> and moderate dilation of the right lateral ventricle <img src='/img/arrows/CC.png'/>.](images/app.statdx.com_image_thumbnail_ddc74acb-a5fe-4147-bc17-3e3862305da7_annotated_true_size_900_quality_90_d599964a_20251018T165124Z.jpg)
+**Extrinsic Mass Effect**
+*Axial FLAIR MR demonstrates a large,  heterogeneous mass in the left frontal lobe <img src='/img/arrows/CS.png'/> with surrounding edema and mass effect with compression of the left lateral ventricle <img src='/img/arrows/CO.png'/> and moderate dilation of the right lateral ventricle <img src='/img/arrows/CC.png'/>.*
+
+![Axial T2 MR demonstrates a large, cystic encephalomalacia in the left frontal and parietal lobes due to chronic infarction <img src='/img/arrows/CC.png'/> with ex-vacuo dilation of the left lateral ventricle <img src='/img/arrows/CS.png'/>.](images/app.statdx.com_image_thumbnail_f987a5f2-594d-4b3a-84d0-640a0b70c03b_annotated_true_size_900_quality_90_e62de461_20251018T165124Z.jpg)
+**Encephalomalacia, General**
+*Axial T2 MR demonstrates a large, cystic encephalomalacia in the left frontal and parietal lobes due to chronic infarction <img src='/img/arrows/CC.png'/> with ex-vacuo dilation of the left lateral ventricle <img src='/img/arrows/CS.png'/>.*
+
+![Axial T2 MR demonstrates a large amount of acute intraventricular hemorrhage with mild dilation of the right lateral ventricle <img src='/img/arrows/CS.png'/>. Note CSF seepage in the peritrigonal region <img src='/img/arrows/CC.png'/>.](1ce39627-5994-4f0b-a77e-c02fcf1d1c66)
+**Intraventricular Hemorrhage**
+*Axial T2 MR demonstrates a large amount of acute intraventricular hemorrhage with mild dilation of the right lateral ventricle <img src='/img/arrows/CS.png'/>. Note CSF seepage in the peritrigonal region <img src='/img/arrows/CC.png'/>.*
+
+![Axial NECT demonstrates a large left subdural hematoma <img src='/img/arrows/BS.png'/> and a small parenchymal hemorrhage <img src='/img/arrows/BO.png'/>, resulting in rightward subfalcine herniation <img src='/img/arrows/CS.png'/>, compression of the left lateral ventricle <img src='/img/arrows/CO.png'/>, and mild dilation of the right lateral ventricle <img src='/img/arrows/CC.png'/>.](b9992ffd-4f31-44e2-8c92-83ab8fad30c1)
+**Herniation Syndromes, Intracranial**
+*Axial NECT demonstrates a large left subdural hematoma <img src='/img/arrows/BS.png'/> and a small parenchymal hemorrhage <img src='/img/arrows/BO.png'/>, resulting in rightward subfalcine herniation <img src='/img/arrows/CS.png'/>, compression of the left lateral ventricle <img src='/img/arrows/CO.png'/>, and mild dilation of the right lateral ventricle <img src='/img/arrows/CC.png'/>.*
+
+![Axial FLAIR MR demonstrates a large surgical defect in the left frontal lobe <img src='/img/arrows/CO.png'/> due to a tumor resection with resultant mild prominence of the left lateral ventricle <img src='/img/arrows/CS.png'/>.](a77eef3e-29e3-44c5-88bc-d67eff223e44)
+**Surgical Defects**
+*Axial FLAIR MR demonstrates a large surgical defect in the left frontal lobe <img src='/img/arrows/CO.png'/> due to a tumor resection with resultant mild prominence of the left lateral ventricle <img src='/img/arrows/CS.png'/>.*
+
+![Axial T1 C+ MR demonstrates enhancing intraventricular mass <img src='/img/arrows/CS.png'/> with obstructive dilation of the left temporal horn <img src='/img/arrows/CO.png'/>.](181895c1-e6ec-4317-a0d8-d85acb1e681a)
+**Obstructive Hydrocephalus**
+*Axial T1 C+ MR demonstrates enhancing intraventricular mass <img src='/img/arrows/CS.png'/> with obstructive dilation of the left temporal horn <img src='/img/arrows/CO.png'/>.*
+
+![Axial T2 MR demonstrates a shunt catheter in the right lateral ventricle <img src='/img/arrows/CS.png'/> with asymmetric lateral ventricles due to overdrainage of the right <img src='/img/arrows/CO.png'/> and mild underdrainage of the left <img src='/img/arrows/CC.png'/>. Note susceptibility artifact <img src='/img/arrows/WS.png'/> due to the shunt reservoir.](6a5a42a2-43a2-4fe6-8dd5-b2b1fc3e83fd)
+**CSF Shunts and Complications**
+*Axial T2 MR demonstrates a shunt catheter in the right lateral ventricle <img src='/img/arrows/CS.png'/> with asymmetric lateral ventricles due to overdrainage of the right <img src='/img/arrows/CO.png'/> and mild underdrainage of the left <img src='/img/arrows/CC.png'/>. Note susceptibility artifact <img src='/img/arrows/WS.png'/> due to the shunt reservoir.*
+
+![Axial T2 MR demonstrates a left lateral intraventricular isointense mass <img src='/img/arrows/CO.png'/> in the trigone with dilatation of the left trigone <img src='/img/arrows/CS.png'/>. Note periventricular edema <img src='/img/arrows/CC.png'/>. Biopsy revealed meningioma.](c60f5671-0335-43af-8efa-e151dbc51c78)
+**Meningioma**
+*Axial T2 MR demonstrates a left lateral intraventricular isointense mass <img src='/img/arrows/CO.png'/> in the trigone with dilatation of the left trigone <img src='/img/arrows/CS.png'/>. Note periventricular edema <img src='/img/arrows/CC.png'/>. Biopsy revealed meningioma.*
+
+![Axial T2 MR demonstrates a well-circumscribed, isointense, left lateral ventricular mass <img src='/img/arrows/CS.png'/> attached to the septum pellucidum with peripheral tiny cysts <img src='/img/arrows/CC.png'/>. Note moderate dilation of the left lateral ventricle <img src='/img/arrows/CO.png'/>. Biopsy revealed neurocytoma.](ebb2adb7-6287-41d0-8a41-de9563c420d8)
+**Neurocytoma, Central**
+*Axial T2 MR demonstrates a well-circumscribed, isointense, left lateral ventricular mass <img src='/img/arrows/CS.png'/> attached to the septum pellucidum with peripheral tiny cysts <img src='/img/arrows/CC.png'/>. Note moderate dilation of the left lateral ventricle <img src='/img/arrows/CO.png'/>. Biopsy revealed neurocytoma.*
+
+![Coronal T2 MR demonstrates asymmetric mild enlargement of the left lateral ventricle <img src='/img/arrows/CO.png'/> due to synechiae <img src='/img/arrows/CS.png'/> obstructing the foramen of Monro.](a22d935b-ac47-4f41-8b5d-57d599e0d11f)
+**Intraventricular Synechiae/Adhesions**
+*Coronal T2 MR demonstrates asymmetric mild enlargement of the left lateral ventricle <img src='/img/arrows/CO.png'/> due to synechiae <img src='/img/arrows/CS.png'/> obstructing the foramen of Monro.*
+
+![Axial T2 MR demonstrates a poorly circumscribed heterogeneous left trigonal mass <img src='/img/arrows/CO.png'/> with internal cysts/necrosis. Note extensive periventricular edema <img src='/img/arrows/CC.png'/>. Biopsy revealed choroid plexus carcinoma.](77fdb2fd-452d-4226-b341-62bf87689ec5)
+**Choroid Plexus Carcinoma**
+*Axial T2 MR demonstrates a poorly circumscribed heterogeneous left trigonal mass <img src='/img/arrows/CO.png'/> with internal cysts/necrosis. Note extensive periventricular edema <img src='/img/arrows/CC.png'/>. Biopsy revealed choroid plexus carcinoma.*
+
+![Axial NECT demonstrates atrophy of the left cerebral hemisphere with encephalomalacia due to antenatal vascular insult. Note the dilated left lateral ventricle <img src='/img/arrows/CS.png'/> and mild overlying calvarial thickening <img src='/img/arrows/CO.png'/>.](71a10f6b-7ad7-4e54-98ae-1784130732b9)
+**Dyke-Davidoff-Masson**
+*Axial NECT demonstrates atrophy of the left cerebral hemisphere with encephalomalacia due to antenatal vascular insult. Note the dilated left lateral ventricle <img src='/img/arrows/CS.png'/> and mild overlying calvarial thickening <img src='/img/arrows/CO.png'/>.*
+
+![Axial T2 MR in a patient with refractory epilepsy due to Rasmussen encephalitis demonstrates left cerebral hemispheric atrophy <img src='/img/arrows/CC.png'/> and mild ex-vacuo dilation of the left lateral ventricle <img src='/img/arrows/CS.png'/>.](71509045-9597-44be-b81f-44e0bc95be4e)
+**Rasmussen Encephalitis**
+*Axial T2 MR in a patient with refractory epilepsy due to Rasmussen encephalitis demonstrates left cerebral hemispheric atrophy <img src='/img/arrows/CC.png'/> and mild ex-vacuo dilation of the left lateral ventricle <img src='/img/arrows/CS.png'/>.*
+
+
+### Additional Images
+
+![Axial T1WI C+ MR shows compression of the left frontal horn <img src='/img/arrows/WS.png'/> by a large, periventricular, enhancing mass <img src='/img/arrows/WC.png'/>, primary CNS lymphoma. Extrinsic mass effect is a common cause of ventricular asymmetry.](images/app.statdx.com_image_thumbnail_9c7a2c27-fa74-474a-a33e-3cfbf2329f76_annotated_true_size_900_quality_90_8cafe5b4_20251018T165124Z.jpg)
+**Extrinsic Mass Effect**
+*Axial T1WI C+ MR shows compression of the left frontal horn <img src='/img/arrows/WS.png'/> by a large, periventricular, enhancing mass <img src='/img/arrows/WC.png'/>, primary CNS lymphoma. Extrinsic mass effect is a common cause of ventricular asymmetry.*
+
+![Axial FLAIR MR demonstrates a left posterior MCA encephalomalacia <img src='/img/arrows/WS.png'/> resulting in mild ex-vacuo dilatation of the left atrium <img src='/img/arrows/WO.png'/>.](images/app.statdx.com_image_thumbnail_d875dfa4-5133-4dd6-9471-a019de504b4a_annotated_true_size_900_quality_90_e15566aa_20251018T165124Z.jpg)
+**Encephalomalacia, General**
+*Axial FLAIR MR demonstrates a left posterior MCA encephalomalacia <img src='/img/arrows/WS.png'/> resulting in mild ex-vacuo dilatation of the left atrium <img src='/img/arrows/WO.png'/>.*
+
+![Axial T2 MR shows right hemiatrophy in Sturge-Weber syndrome. Chronic venous ischemia leads to progressive hemiatrophy. Note the ipsilateral large right ventricle <img src='/img/arrows/WO.png'/> due to volume loss.](images/app.statdx.com_image_thumbnail_370d0b50-9617-4697-8005-d759cf146130_annotated_true_size_900_quality_90_83c359ec_20251018T165124Z.jpg)
+**Encephalomalacia, General**
+*Axial T2 MR shows right hemiatrophy in Sturge-Weber syndrome. Chronic venous ischemia leads to progressive hemiatrophy. Note the ipsilateral large right ventricle <img src='/img/arrows/WO.png'/> due to volume loss.*
+
+![Axial NECT shows a basal ganglia hypertensive hemorrhage <img src='/img/arrows/WS.png'/> with intraventricular extension <img src='/img/arrows/WO.png'/>. Associated midline shift results in dilation of the contralateral ventricles <img src='/img/arrows/WC.png'/> from foramen of Monro obstruction.](4897b7a6-5a0f-49c0-8a96-26f7653455b6)
+**Intraventricular Hemorrhage**
+*Axial NECT shows a basal ganglia hypertensive hemorrhage <img src='/img/arrows/WS.png'/> with intraventricular extension <img src='/img/arrows/WO.png'/>. Associated midline shift results in dilation of the contralateral ventricles <img src='/img/arrows/WC.png'/> from foramen of Monro obstruction.*
+
+![Coronal FLAIR MR shows a diffusely enlarged hyperintense supratentorial cortex <img src='/img/arrows/WS.png'/> compared to the cerebellum in this patient in longstanding status epilepticus. Disproportionate left hemisphere involvement has resulted in left ventricular compression <img src='/img/arrows/WO.png'/>, right foramen of Monro outlet obstruction, and dilation of the right ventricular system <img src='/img/arrows/WC.png'/>.](b73d4ba3-3f44-41f0-8763-5a8ef431e21a)
+**Herniation Syndromes, Intracranial**
+*Coronal FLAIR MR shows a diffusely enlarged hyperintense supratentorial cortex <img src='/img/arrows/WS.png'/> compared to the cerebellum in this patient in longstanding status epilepticus. Disproportionate left hemisphere involvement has resulted in left ventricular compression <img src='/img/arrows/WO.png'/>, right foramen of Monro outlet obstruction, and dilation of the right ventricular system <img src='/img/arrows/WC.png'/>.*
+
+![Coronal T1WI C+ MR shows a right hemispheric, subacute, subdural hematoma causing subfalcine <img src='/img/arrows/WC.png'/>  and uncal <img src='/img/arrows/WO.png'/> herniation. Mass effect compresses the right frontal horn. The left ventricle <img src='/img/arrows/BO.png'/> is enlarged from foramen of Monro obstruction.](babb7bb2-a880-4e0d-84e4-a4a72ba57ee1)
+**Herniation Syndromes, Intracranial**
+*Coronal T1WI C+ MR shows a right hemispheric, subacute, subdural hematoma causing subfalcine <img src='/img/arrows/WC.png'/>  and uncal <img src='/img/arrows/WO.png'/> herniation. Mass effect compresses the right frontal horn. The left ventricle <img src='/img/arrows/BO.png'/> is enlarged from foramen of Monro obstruction.*
+
+![Coronal T2WI MR shows right temporal viral encephalitis causing local mass effect <img src='/img/arrows/WO.png'/>. The left lateral ventricle <img src='/img/arrows/WS.png'/> is larger from foramen of Monro obstruction due to midline shift.](ac578239-383c-479c-9fd1-ec8b74c4c90d)
+**Herniation Syndromes, Intracranial**
+*Coronal T2WI MR shows right temporal viral encephalitis causing local mass effect <img src='/img/arrows/WO.png'/>. The left lateral ventricle <img src='/img/arrows/WS.png'/> is larger from foramen of Monro obstruction due to midline shift.*
+
+![Axial T2WI MR shows widening of right foramen of Monro <img src='/img/arrows/WS.png'/>, septum pellucidum deviation <img src='/img/arrows/BS.png'/>, and an enlarged right lateral ventricle <img src='/img/arrows/WO.png'/> in this tuberous sclerosis patient with remote tumor resection.](166a8b5f-51ff-4bff-a262-2f54eae8dec6)
+**Surgical Defects**
+*Axial T2WI MR shows widening of right foramen of Monro <img src='/img/arrows/WS.png'/>, septum pellucidum deviation <img src='/img/arrows/BS.png'/>, and an enlarged right lateral ventricle <img src='/img/arrows/WO.png'/> in this tuberous sclerosis patient with remote tumor resection.*
+
+![Axial NECT shows marked enlargement of the left lateral ventricle with bowing of septum pellucidum across midline <img src='/img/arrows/WS.png'/>  and transependymal CSF migration <img src='/img/arrows/WO.png'/> indicating acute obstruction. Findings were related to a small atrial diverticulum.](111d8d26-88f6-43d3-8ddb-407a85e2707e)
+**Obstructive Hydrocephalus**
+*Axial NECT shows marked enlargement of the left lateral ventricle with bowing of septum pellucidum across midline <img src='/img/arrows/WS.png'/>  and transependymal CSF migration <img src='/img/arrows/WO.png'/> indicating acute obstruction. Findings were related to a small atrial diverticulum.*
+
+![Axial T1WI C+ MR shows a colloid cyst <img src='/img/arrows/WS.png'/> believed to be complicated by inflammatory changes. Obstruction of the left foramen of Monro causes unilateral left lateral ventricle dilation <img src='/img/arrows/WO.png'/>.](f99e392c-9132-4bdd-b2fb-665f8ff10dd3)
+**Obstructive Hydrocephalus**
+*Axial T1WI C+ MR shows a colloid cyst <img src='/img/arrows/WS.png'/> believed to be complicated by inflammatory changes. Obstruction of the left foramen of Monro causes unilateral left lateral ventricle dilation <img src='/img/arrows/WO.png'/>.*
+
+![Axial T2WI MR shows a medial atrial diverticulum <img src='/img/arrows/WS.png'/>, a rare complication of severe hydrocephalus. CSF pouch herniates inferomedially through tentorial incisura.](51902a9b-bfb3-4df5-b937-6d3eb682f0f6)
+**Obstructive Hydrocephalus**
+*Axial T2WI MR shows a medial atrial diverticulum <img src='/img/arrows/WS.png'/>, a rare complication of severe hydrocephalus. CSF pouch herniates inferomedially through tentorial incisura.*
+
+![Coronal T1WI C+ MR shows typical case of coccidioidomycosis meningitis. Note marked enhancement of basal cisterns <img src='/img/arrows/BS.png'/> and asymmetric ventricular enlargement <img src='/img/arrows/WS.png'/> from CSF obstruction.](c4b489b1-dc1a-4d23-84fc-a62cd35c8b12)
+**Obstructive Hydrocephalus**
+*Coronal T1WI C+ MR shows typical case of coccidioidomycosis meningitis. Note marked enhancement of basal cisterns <img src='/img/arrows/BS.png'/> and asymmetric ventricular enlargement <img src='/img/arrows/WS.png'/> from CSF obstruction.*
+
+![Axial T1WI C+ MR shows a lobulated, nonenhancing mass <img src='/img/arrows/WS.png'/> in the lateral ventricle atrium, a choroid plexus xanthogranuloma. This degenerative cyst of the choroid plexus is often found incidentally in older patients.](0f9bad8c-233c-480f-adc5-7eb1ab83f856)
+**Choroid Plexus Cyst**
+*Axial T1WI C+ MR shows a lobulated, nonenhancing mass <img src='/img/arrows/WS.png'/> in the lateral ventricle atrium, a choroid plexus xanthogranuloma. This degenerative cyst of the choroid plexus is often found incidentally in older patients.*
+
+![Axial T1WI C+ MR shows ventriculitis with asymmetric lateral ventricles related to a temporal lobe abscess <img src='/img/arrows/WS.png'/> rupture and meningitis <img src='/img/arrows/WC.png'/>. Note ventriculomegaly and ventricular wall enhancement <img src='/img/arrows/WO.png'/> characteristic of ventriculitis.](792dc081-566e-4513-987f-ec30914d3bcf)
+**Ventriculitis**
+*Axial T1WI C+ MR shows ventriculitis with asymmetric lateral ventricles related to a temporal lobe abscess <img src='/img/arrows/WS.png'/> rupture and meningitis <img src='/img/arrows/WC.png'/>. Note ventriculomegaly and ventricular wall enhancement <img src='/img/arrows/WO.png'/> characteristic of ventriculitis.*
+
+![Axial CECT shows marked ventriculomegaly and ependymal enhancement <img src='/img/arrows/WS.png'/>. A dependent debris level <img src='/img/arrows/WC.png'/> is noted in both lateral ventricles. Ventriculitis has resulted from abscess <img src='/img/arrows/WO.png'/> rupture.](288f6dcf-fe0a-4dbf-809a-c0654c4a32c8)
+**Ventriculitis**
+*Axial CECT shows marked ventriculomegaly and ependymal enhancement <img src='/img/arrows/WS.png'/>. A dependent debris level <img src='/img/arrows/WC.png'/> is noted in both lateral ventricles. Ventriculitis has resulted from abscess <img src='/img/arrows/WO.png'/> rupture.*
+
+![Axial NECT shows an infant with hydrocephalus after placement of a right frontal ventricular drain <img src='/img/arrows/WS.png'/>. The shunt did not cross midline. The left lateral ventricle remained enlarged, and the right became slit-like.](5fc74921-60fe-4ec5-b99e-8667a5b6d288)
+**CSF Shunts and Complications**
+*Axial NECT shows an infant with hydrocephalus after placement of a right frontal ventricular drain <img src='/img/arrows/WS.png'/>. The shunt did not cross midline. The left lateral ventricle remained enlarged, and the right became slit-like.*
+
+![Axial T2WI MR shows marked enlargement of the isolated right lateral ventricle with transependymal flow of CSF <img src='/img/arrows/WC.png'/> indicating acute obstruction. Note left shunt <img src='/img/arrows/WS.png'/>  and completely decompressed left lateral ventricle.](ce67f32e-2900-499f-8122-83108e8cb3f9)
+**CSF Shunts and Complications**
+*Axial T2WI MR shows marked enlargement of the isolated right lateral ventricle with transependymal flow of CSF <img src='/img/arrows/WC.png'/> indicating acute obstruction. Note left shunt <img src='/img/arrows/WS.png'/>  and completely decompressed left lateral ventricle.*
+
+![Axial NECT shows asymmetric left ventricular dilation <img src='/img/arrows/WS.png'/> post shunting <img src='/img/arrows/WO.png'/>. Shunt tip may be occluded from clot <img src='/img/arrows/WC.png'/> or from imperforate septum, preventing drainage of the left ventricular system.](d7b146cb-1f10-4d4a-a067-85779240fbfb)
+**CSF Shunts and Complications**
+*Axial NECT shows asymmetric left ventricular dilation <img src='/img/arrows/WS.png'/> post shunting <img src='/img/arrows/WO.png'/>. Shunt tip may be occluded from clot <img src='/img/arrows/WC.png'/> or from imperforate septum, preventing drainage of the left ventricular system.*
+
+![Axial T2WI FS MR shows a hypointense choroid plexus mass <img src='/img/arrows/WS.png'/> in the atrium of the left lateral ventricle that enhanced intensely (not shown). Note striking surrounding vasogenic edema <img src='/img/arrows/WC.png'/> in adjacent brain parenchyma, thought due to locally obstructed CSF.](d39a3243-21fc-4d93-9a3e-85e6a329c81d)
+**Meningioma**
+*Axial T2WI FS MR shows a hypointense choroid plexus mass <img src='/img/arrows/WS.png'/> in the atrium of the left lateral ventricle that enhanced intensely (not shown). Note striking surrounding vasogenic edema <img src='/img/arrows/WC.png'/> in adjacent brain parenchyma, thought due to locally obstructed CSF.*
+
+![Axial T1WI C+ MR demonstrates a mildly enhancing and heterogeneous mass arising from the septum pellucidum <img src='/img/arrows/WS.png'/>. Note asymmetric dilatation of the right lateral ventricle <img src='/img/arrows/WO.png'/>.](1c64172a-f7fe-40df-8387-08f484c5cbad)
+**Neurocytoma, Central**
+*Axial T1WI C+ MR demonstrates a mildly enhancing and heterogeneous mass arising from the septum pellucidum <img src='/img/arrows/WS.png'/>. Note asymmetric dilatation of the right lateral ventricle <img src='/img/arrows/WO.png'/>.*
+
+![Axial T1WI C+ MR shows enhancement within the mass in the atrium of the lateral ventricle <img src='/img/arrows/WS.png'/> with an encysted asymmetrically larger left lateral ventricle.](4df1735f-b3a7-4ab4-9e73-ce5d331abb62)
+**Choroid Plexus Papilloma**
+*Axial T1WI C+ MR shows enhancement within the mass in the atrium of the lateral ventricle <img src='/img/arrows/WS.png'/> with an encysted asymmetrically larger left lateral ventricle.*
+
+![Axial T1WI C+ MR shows asymmetric lateral ventricles caused by a giant neurocysticercosis cyst <img src='/img/arrows/WS.png'/> in the body of the left lateral ventricle.](fcfcfeb1-c938-47be-ba9e-a639c55bbdd3)
+**Neurocysticercosis**
+*Axial T1WI C+ MR shows asymmetric lateral ventricles caused by a giant neurocysticercosis cyst <img src='/img/arrows/WS.png'/> in the body of the left lateral ventricle.*
+
+![Axial T1WI C+ FS MR shows a large mass in the atrium of the right lateral ventricle <img src='/img/arrows/WC.png'/> with a trapped, encysted occipital horn <img src='/img/arrows/WO.png'/>. Ependymal enhancement represents tumor spread from choroidal metastasis.](2bb8e963-0d65-4974-ae8d-429abcee49df)
+**Intraventricular Synechiae/Adhesions**
+*Axial T1WI C+ FS MR shows a large mass in the atrium of the right lateral ventricle <img src='/img/arrows/WC.png'/> with a trapped, encysted occipital horn <img src='/img/arrows/WO.png'/>. Ependymal enhancement represents tumor spread from choroidal metastasis.*
+
+![Axial T1WI C+ MR shows an asymmetrically larger right atrium <img src='/img/arrows/WS.png'/> in this patient with Sturge-Weber syndrome. Note associated ipsilateral enlarged frontal sinus <img src='/img/arrows/BO.png'/> and calvarial thickening <img src='/img/arrows/BC.png'/>.](29370a1b-3c42-4629-8032-765ef4ce7c56)
+**Dyke-Davidoff-Masson**
+*Axial T1WI C+ MR shows an asymmetrically larger right atrium <img src='/img/arrows/WS.png'/> in this patient with Sturge-Weber syndrome. Note associated ipsilateral enlarged frontal sinus <img src='/img/arrows/BO.png'/> and calvarial thickening <img src='/img/arrows/BC.png'/>.*
+
+![Axial CECT shows enlargement of the right hemisphere and lateral ventricle <img src='/img/arrows/WS.png'/> compared to the left side. Expansion of the hemisphere is mostly due to increased white matter. An enlarged, often deformed, lateral ventricle on the abnormal side is typical.](9a0ef691-0fe7-474a-86d7-121a23736b79)
+**Hemimegalencephaly**
+*Axial CECT shows enlargement of the right hemisphere and lateral ventricle <img src='/img/arrows/WS.png'/> compared to the left side. Expansion of the hemisphere is mostly due to increased white matter. An enlarged, often deformed, lateral ventricle on the abnormal side is typical.*
+
+![Axial FLAIR MR shows a cyst enlarging the left lateral ventricle with signal intensity isointense to CSF <img src='/img/arrows/WS.png'/>. There was no enhancement of the cyst wall, typical of ependymal cyst.](5dc6448b-9e90-480c-92c4-b59914acd3c2)
+**Ependymal Cyst**
+*Axial FLAIR MR shows a cyst enlarging the left lateral ventricle with signal intensity isointense to CSF <img src='/img/arrows/WS.png'/>. There was no enhancement of the cyst wall, typical of ependymal cyst.*
+
+![Axial FLAIR MR shows a cystic lesion arising from the ependymal lining of the left temporal horn <img src='/img/arrows/CS.png'/>, consistent with an ependymal cyst. The lesion followed CSF signal on every sequence.](6b71914c-51db-4512-973b-d4b49427919c)
+**Ependymal Cyst**
+*Axial FLAIR MR shows a cystic lesion arising from the ependymal lining of the left temporal horn <img src='/img/arrows/CS.png'/>, consistent with an ependymal cyst. The lesion followed CSF signal on every sequence.*
+
+![Axial T1WI MR demonstrates a right parietal shunt catheter with its tip <img src='/img/arrows/WS.png'/> in the right frontal horn in a patient with congenital aqueductal stenosis. The right lateral ventricle is collapsed, while the 3rd <img src='/img/arrows/CO.png'/> and left lateral ventricles <img src='/img/arrows/CC.png'/> are moderately dilated.](a93b23ad-da88-4c04-9b31-d3a582cad7c2)
+**CSF Shunts and Complications**
+*Axial T1WI MR demonstrates a right parietal shunt catheter with its tip <img src='/img/arrows/WS.png'/> in the right frontal horn in a patient with congenital aqueductal stenosis. The right lateral ventricle is collapsed, while the 3rd <img src='/img/arrows/CO.png'/> and left lateral ventricles <img src='/img/arrows/CC.png'/> are moderately dilated.*
+
+![Axial T1WI C+ MR shows ependymal enhancement and mild asymmetric dilatation of the left occipital horn <img src='/img/arrows/CO.png'/> in ventriculitis. There is also asymmetric enhancement of the adjacent choroid plexus consistent with choroid plexitis <img src='/img/arrows/WO.png'/>.](00e493e3-51d9-420f-be10-b731a98a2fc1)
+**Ventriculitis**
+*Axial T1WI C+ MR shows ependymal enhancement and mild asymmetric dilatation of the left occipital horn <img src='/img/arrows/CO.png'/> in ventriculitis. There is also asymmetric enhancement of the adjacent choroid plexus consistent with choroid plexitis <img src='/img/arrows/WO.png'/>.*
+
+![Axial T2WI MR shows a large, hyperintense choroid plexus cyst <img src='/img/arrows/CS.png'/> in a newborn. The lesion increased in size on sequential imaging, requiring endoscopic fenestration.](273e2721-a959-4b65-82dd-32f8f9fa8623)
+**Choroid Plexus Cyst**
+*Axial T2WI MR shows a large, hyperintense choroid plexus cyst <img src='/img/arrows/CS.png'/> in a newborn. The lesion increased in size on sequential imaging, requiring endoscopic fenestration.*
+
+![Axial FLAIR MR shows asymmetric dilatation of the left frontal horn <img src='/img/arrows/CS.png'/> and surrounding gliosis following the resection of an intraaxial metastasis. Part of the surgical tract is seen <img src='/img/arrows/CO.png'/>. Note multiple additional metastatic lesions <img src='/img/arrows/WS.png'/> in the right cerebral hemisphere.](53f0bb77-3081-483a-ba27-25e293db386b)
+**Surgical Defects**
+*Axial FLAIR MR shows asymmetric dilatation of the left frontal horn <img src='/img/arrows/CS.png'/> and surrounding gliosis following the resection of an intraaxial metastasis. Part of the surgical tract is seen <img src='/img/arrows/CO.png'/>. Note multiple additional metastatic lesions <img src='/img/arrows/WS.png'/> in the right cerebral hemisphere.*
+
+![Axial NECT demonstrates a large left frontal intraparenchymal hematoma <img src='/img/arrows/BO.png'/> causing subfalcine herniation to the right <img src='/img/arrows/CS.png'/>. The left lateral ventricle is effaced. The posterior right lateral ventricle is mildly dilated <img src='/img/arrows/CO.png'/>.](2ed18dfe-fece-449e-806e-9274ebd2cdd6)
+**Herniation Syndromes, Intracranial**
+*Axial NECT demonstrates a large left frontal intraparenchymal hematoma <img src='/img/arrows/BO.png'/> causing subfalcine herniation to the right <img src='/img/arrows/CS.png'/>. The left lateral ventricle is effaced. The posterior right lateral ventricle is mildly dilated <img src='/img/arrows/CO.png'/>.*
+
+![Axial NECT shows a large amount of intraventricular hemorrhage <img src='/img/arrows/CS.png'/> resulting in moderate asymmetric expansion of the left lateral ventricle. A smaller amount of layering blood products is seen in the right lateral ventricle <img src='/img/arrows/CO.png'/>.](3e87fdc0-f72c-4519-8fa8-407d3ca749a8)
+**Intraventricular Hemorrhage**
+*Axial NECT shows a large amount of intraventricular hemorrhage <img src='/img/arrows/CS.png'/> resulting in moderate asymmetric expansion of the left lateral ventricle. A smaller amount of layering blood products is seen in the right lateral ventricle <img src='/img/arrows/CO.png'/>.*
+
+![Axial T2WI MR shows mild, asymmetric, right hemispheric volume loss with prominent sulci <img src='/img/arrows/CS.png'/> and mild, asymmetric, right lateral ventricle dilatation <img src='/img/arrows/CO.png'/> in a pediatric patient with Rasmussen encephalitis.](de0627e1-81c9-498e-9a0e-9f525bf8351e)
+**Rasmussen Encephalitis**
+*Axial T2WI MR shows mild, asymmetric, right hemispheric volume loss with prominent sulci <img src='/img/arrows/CS.png'/> and mild, asymmetric, right lateral ventricle dilatation <img src='/img/arrows/CO.png'/> in a pediatric patient with Rasmussen encephalitis.*
+
+![Axial FLAIR MR shows a round mass in the right occipital lobe <img src='/img/arrows/CS.png'/> (primary CNS lymphoma) that effaces the adjacent right occipital horn and atrium <img src='/img/arrows/CO.png'/>. Extrinsic mass effect is a common cause of ventricular asymmetry and compression.](images/app.statdx.com_image_thumbnail_e0671196-28db-4361-9b63-cdc32902585b_annotated_true_size_900_quality_90_9b78cd11_20251018T165124Z.jpg)
+**Extrinsic Mass Effect**
+*Axial FLAIR MR shows a round mass in the right occipital lobe <img src='/img/arrows/CS.png'/> (primary CNS lymphoma) that effaces the adjacent right occipital horn and atrium <img src='/img/arrows/CO.png'/>. Extrinsic mass effect is a common cause of ventricular asymmetry and compression.*
+
+![Axial T1WI C+ MR demonstrates a heterogeneous enhancing mass <img src='/img/arrows/CS.png'/> arising from the septum pellucidum, a pathologically proven central neurocytoma. Note moderate asymmetric dilatation of the right lateral ventricle <img src='/img/arrows/CO.png'/>.](ec4b2b8a-cd64-45e6-9430-1727c705ee35)
+**Neurocytoma, Central**
+*Axial T1WI C+ MR demonstrates a heterogeneous enhancing mass <img src='/img/arrows/CS.png'/> arising from the septum pellucidum, a pathologically proven central neurocytoma. Note moderate asymmetric dilatation of the right lateral ventricle <img src='/img/arrows/CO.png'/>.*
+
+![Axial FLAIR MR shows a left thalamic expansile mass <img src='/img/arrows/CS.png'/>, a glioblastoma, which demonstrated heterogeneous enhancement (not shown). It protrudes into and obstructs the left ventricular atrium, which is asymmetrically dilated <img src='/img/arrows/CO.png'/>.](cfe69151-f87a-4abc-aa1a-01fa9586fa5f)
+**Obstructive Hydrocephalus**
+*Axial FLAIR MR shows a left thalamic expansile mass <img src='/img/arrows/CS.png'/>, a glioblastoma, which demonstrated heterogeneous enhancement (not shown). It protrudes into and obstructs the left ventricular atrium, which is asymmetrically dilated <img src='/img/arrows/CO.png'/>.*
+
+![Axial T2WI MR demonstrates generalized left hemispheric encephalomalacia <img src='/img/arrows/CS.png'/> following necrotizing encephalitis of unknown origin. There is resultant mild ex-vacuo dilatation of the left lateral ventricle <img src='/img/arrows/CO.png'/>.](images/app.statdx.com_image_thumbnail_1c54ab83-8081-45a8-960e-a7f50c31cce6_annotated_true_size_900_quality_90_6554d649_20251018T165130Z.jpg)
+**Encephalomalacia, General**
+*Axial T2WI MR demonstrates generalized left hemispheric encephalomalacia <img src='/img/arrows/CS.png'/> following necrotizing encephalitis of unknown origin. There is resultant mild ex-vacuo dilatation of the left lateral ventricle <img src='/img/arrows/CO.png'/>.*
+
+![Axial T1WI C+ MR shows an avidly enhancing, lobulated mass arising from the right ventricular atrium <img src='/img/arrows/CS.png'/>, a meningioma. Note the mild asymmetric dilatation of the left lateral ventricle <img src='/img/arrows/CO.png'/>.](b426de7c-024c-4f25-ab33-1e7a567fe147)
+**Meningioma**
+*Axial T1WI C+ MR shows an avidly enhancing, lobulated mass arising from the right ventricular atrium <img src='/img/arrows/CS.png'/>, a meningioma. Note the mild asymmetric dilatation of the left lateral ventricle <img src='/img/arrows/CO.png'/>.*
+
+![Axial T2WI MR shows lateral ventricles with the right <img src='/img/arrows/CS.png'/> being larger than the left, representing a normal variant. Note mild bowing of the septum pellucidum across the midline <img src='/img/arrows/CC.png'/>.](images/app.statdx.com_image_thumbnail_7a290571-170f-4a98-8381-da762b17ab09_annotated_true_size_900_quality_90_97b6ac24_20251018T165124Z.jpg)
+**Normal Variant**
+*Axial T2WI MR shows lateral ventricles with the right <img src='/img/arrows/CS.png'/> being larger than the left, representing a normal variant. Note mild bowing of the septum pellucidum across the midline <img src='/img/arrows/CC.png'/>.*
+

docs_md/articles/benign-enlarged-subarachnoid-spaces_3da4fec0-6e87-4bcc-bd66-b4a5d1984f6e.md

@@ -0,0 +1,468 @@
+---
+title: "Benign Enlarged Subarachnoid Spaces"
+docid: "3da4fec0-6e87-4bcc-bd66-b4a5d1984f6e"
+authors:
+  - key: "47381de4-c9fd-4999-8dd0-1808cd72db6b"
+    value: "Luke L. Linscott, MD"
+  - key: "b2e6dabb-ee1c-42a4-a332-9f0814c1c607"
+    value: "Surjith Vattoth, MD, FRCR"
+breadcrumbs:
+  -
+    name: "Brain"
+    slug: "brain"
+    treeNodeId: "6d8829f1-14d7-45af-8675-255189aa526a"
+  -
+    name: "Diagnosis"
+    slug: "diagnosis"
+    treeNodeId: "51c00394-446e-4a38-94af-d3b1d14d34e8"
+  -
+    name: "Anatomy-Based Diagnoses"
+    slug: "anatomy-based-diagnoses"
+    treeNodeId: "529d3e33-f508-498c-bc70-cf962e81e629"
+  -
+    name: "Ventricles and Cisterns"
+    slug: "ventricles-and-cisterns"
+    treeNodeId: "33b267f0-908c-4c77-81f8-f6135d1bc592"
+  -
+    name: "Normal Variants"
+    slug: "normal-variants"
+    treeNodeId: "bf92256f-cdff-4bcd-8420-d876b9e4031a"
+  -
+    name: "Benign Enlarged Subarachnoid Spaces"
+    slug: "benign-enlarged-subarachnoid-spaces"
+    treeNodeId: null
+category: "Brain"
+documentVersionId: "223d884d-2cb4-42bf-b5ad-ed2ccbd89644"
+imageCount: 20
+lastUpdated: "07/31/20"
+pageDescription: "Benign Enlarged Subarachnoid Spaces"
+pageKeywords: "Brain, Diagnosis, Anatomy-Based Diagnoses, Ventricles and Cisterns, Normal Variants, Benign Enlarged Subarachnoid Spaces"
+pageTitle: "Benign Enlarged Subarachnoid Spaces | STATdx"
+enhancedTitle: "Benign Enlarged Subarachnoid Spaces"
+type: "DX"
+references: true
+ddx: true
+cases: 2
+breadcrumbs:
+  - "Brain"
+  - "Diagnosis"
+  - "Anatomy-Based Diagnoses"
+  - "Ventricles and Cisterns"
+  - "Normal Variants"
+  - "Benign Enlarged Subarachnoid Spaces"
+---
+# KEY FACTS
+
+- ## Terminology
+  
+  
+    - Idiopathic enlargement of subarachnoid spaces (SAS) during infancy
+- ## Imaging
+  
+  
+    - Primary imaging modality: US
+          - CT/MR used if fontanelle closing or to further investigate atypical clinical/US findings
+    - Best clue: Enlarged SAS and ↑ orbitofrontal circumference (OFC) (> 95th percentile)
+          - Ventricles may be mildly enlarged
+    - Symmetric bifrontal and bitemporal SAS
+    - All modalities show veins coursing through SAS
+    - SAS follow CSF appearance on all modalities
+    - No compression of veins or gyri
+    - No inward displacement of arachnoid membrane by subdural fluid; small, nonhemorrhagic, subdural collections seen in ~ 4% of patients with enlarged SAS
+- ## Top Differential Diagnoses
+  
+  
+    - Atrophy
+    - Acquired progressive communicating hydrocephalus
+    - Nonaccidental trauma (NAT)
+- ## Pathology
+  
+  
+    - Etiology uncertain: Immature CSF drainage pathways likely
+    - Family history of macrocephaly > 80%
+- ## Clinical Issues
+  
+  
+    - Mild developmental delay alone should not prompt further imaging or subspecialty evaluation
+          - Further evaluation required only in setting of focal neurologic signs &/or developmental regression
+    - Consider NAT if enlarged extraaxial spaces atypical
+          - Moderate/large/complex subdural collection → NAT work-up
+    - SAS enlargement and developmental delay typically resolve without therapy by 2 years of age
+    - No treatment necessary
+- ## Diagnostic Checklist
+  
+  
+    - Further evaluation with brain MR or CT if US atypical
+    - Even small/simple subdural collections should be discussed with referring clinician to identify any concerns for NAT that merit further work-up
+
+# TERMINOLOGY
+
+- ## Synonyms
+  
+  
+    - Benign enlargement of subarachnoid spaces of infancy (BESSI)
+    - Benign external hydrocephalus
+    - Benign extracerebral fluid collections of infancy
+    - Benign communicating hydrocephalus
+    - Physiologic extraventricular obstructive hydrocephalus
+    - Benign macrocephaly of infancy
+- ## Definitions
+  
+  
+    - Enlarged subarachnoid spaces (SAS) in patient < 1 year of age with macrocrania [head circumference (HC) > 95%]
+
+# IMAGING
+
+- ## General Features
+  
+  
+    - ### Best diagnostic clue
+      
+      
+          - Symmetric bilateral SAS enlargement ± mild ventriculomegaly
+                  - Patient with normal or mildly delayed development
+    - ### Location
+      
+      
+          - Enlarged SAS in infant with macrocrania
+                  - Symmetric at bifrontal and bitemporal SAS
+    - ### Size
+      
+      
+          - Normal SAS values differ significantly between studies
+                  - Normal maximum width peaks at 28 postnatal weeks (7 months of age)
+                  - Interhemispheric width: 95th percentile: ~ 8 mm
+                            - Widest distance between hemispheres
+                  - Craniocortical width: 95th percentile: ~ 10 mm
+                            - Widest vertical distance between brain and inner table of calvarium
+                  - Sinocortical width: 95th percentile: ~ 7 mm
+                            - Widest distance between cortex and superior sagittal sinus
+    - ### Morphology
+      
+      
+          - CSF space follows (not flattens) gyral contour
+- ## Radiographic Findings
+  
+  
+    - Radiography
+          - ↑ craniofacial ratio
+- ## CT Findings
+  
+  
+    - ### NECT
+      
+      
+          - Enlarged SAS with normal sulci; no hemorrhage
+          - Enlarged cisterns (especially suprasellar/chiasmatic)
+    - ### CECT
+      
+      
+          - Demonstrates veins traversing SAS
+          - No abnormal meningeal enhancement
+- ## MR Findings
+  
+  
+    - ### T1WI
+      
+      
+          - Normal brain parenchyma without edema
+          - Small subdural collections sometimes visible
+    - ### T2WI
+      
+      
+          - Arachnoid membranes
+          - Small nonhemorrhagic subdural collections in ~ 4%
+    - ### FLAIR
+      
+      
+          - SAS fluid follows CSF signal on all sequences
+          - Incomplete signal suppression in subdural collections
+    - ### DWI
+      
+      
+          - ↑ fractional anisotropy and mean diffusivity in brain of patients with enlarged SAS compared to controls
+                  - Normalizes over time with resolution of SAS enlargement
+    - ### T1WI C+
+      
+      
+          - Demonstrates veins traversing SAS
+    - SSFSE
+          - May be used for follow-up to avoid sedation in children
+- ## Ultrasonographic Findings
+  
+  
+    - ### Grayscale ultrasound
+      
+      
+          - Primary modality used whenever possible
+          - Symmetric enlargement of bifrontal SAS
+          - ± mild ventricular enlargement
+    - ### Color Doppler
+      
+      
+          - Cortical veins seen within subarachnoid fluid space 
+                  - No mass effect displacing veins against pia
+                  - No inward displacement of arachnoid membrane by subdural fluid
+          - Subdural collections lack traversing veins
+- ## Imaging Recommendations
+  
+  
+    - ### Best imaging tool
+      
+      
+          - US if acoustic window available
+          - CT/MR if no acoustic window available
+    - ### Protocol advice
+      
+      
+          - Doppler sonography: Documents veins traversing SAS
+          - Linear high-resolution US most sensitive for detection of associated subdural fluid
+          - After diagnosis, best follow-up: Clinical monitoring of HC and development of any neurologic findings
+          - Follow-up with MR/CT typically not necessary, unless
+                  - Focal neurologic signs/symptoms
+                  - Suspicion for subdural collection on US
+
+# DIFFERENTIAL DIAGNOSIS
+
+- ## Atrophy
+  
+  
+    - Small HC; sulcal prominence out of proportion
+          - Forehead "pointed" due to metopic fusion
+- ## Incidental Bilateral Subdural Fluid Collections
+  
+  
+    - Subdural fluid not normally visualized
+          - Small, nonhemorrhagic subdural collections seen in 4% of benign macrocrania patients
+          - Characterized by crescentic fluid collection separating dura from arachnoid
+                  - No cortical veins traversing subdural space
+                  - Discrete arachnoid membrane displaced toward cortex; may be compressing SAS veins
+                  - May have different signal intensity on PD and other MR sequences compared to CSF
+          - Discuss need for further work-up with referring clinician
+                  - Close clinical follow-up at minimum; work-up for nonaccidental trauma (NAT) at discretion of clinician
+- ## Nonaccidental Trauma
+  
+  
+    - Moderate/large or hemorrhagic subdurals or unusual clinical findings should raise concern
+- [Glutaric Aciduria Type 1](/document/glutaric-acidemia-type-1/55db6f3e-1d78-4bc6-b366-68b2d37e5d80)
+    - Enlarged sylvian fissures with delayed myelination
+    - Subdural collections may be present
+    - T2-hyperintense basal ganglia
+- ## Elevated Venous Pressures
+  
+  
+    - Causes: Cardiac disease, internal jugular vein sacrifice for ECMO, arteriovenous fistula, or sinus venous thrombosis
+- ## Communicating Hydrocephalus
+  
+  
+    - Often post hemorrhagic/post inflammatory/neoplastic
+          - Density of extraaxial collection does not = CSF
+    - Achondroplasia and other skull base anomalies
+          - Coarctation of foramen magnum (narrow)
+
+# PATHOLOGY
+
+- ## General Features
+  
+  
+    - ### Etiology
+      
+      
+          - Remains incompletely understood
+          - Immature CSF drainage pathways: Most accepted theory
+                  - CSF primarily drained via extracellular space → capillaries
+                  - Pacchionian granulations (PGs) do not mature until 18 months
+                  - PGs then displaced into veins (as Starling-type resistors)
+                  - PGs regulate venous drainage of CSF when fontanels close
+                  - Benign SAS enlargement usually resolves at that time
+          - Disproportionate growth of skull and brain
+                  - Faster growth of skull results in ↑ SAS ± ↑ ventricles
+                  - This theory helps to explain frequent identification of subdural fluid collections
+          - Family history of macrocephaly > 80%
+    - ### Associated abnormalities
+      
+      
+          - Subdural collections (typically small and incidental) in ~ 4%
+          - Predisposition to bleed with minor trauma: Controversial
+                  - Possibility of ↑ risk for bridging vein injury and subdural collection/hematoma in absence of major trauma
+                  - Venous "stretching" implicated
+          - May ↑ risk of arachnoid cyst development compared to normal population
+- ## Gross Pathologic & Surgical Features
+  
+  
+    - Deep/prominent but otherwise normal-appearing SAS
+    - No pathologic membranes
+- ## Microscopic Features
+  
+  
+    - Ependymal damage not seen in benign SAS enlargement
+
+# CLINICAL ISSUES
+
+- ## Presentation
+  
+  
+    - ### Most common signs/symptoms
+      
+      
+          - Macrocrania: HC > 95th percentile
+          - Frontal bossing
+          - No signs of elevated intracranial pressure (ICP); normal pressure on lumbar puncture
+          - Danger signs
+                  - Elevated ICP
+                  - Persistent or rapid deviation of HC from normal curve
+                  - Developmental regression, focal neurologic signs, vomiting, bruising
+    - ### Other signs/symptoms
+      
+      
+          - Mild developmental delay common (20-50%) and usually resolves over time
+                  - Should not necessarily prompt further evaluation
+    - ### Clinical profile
+      
+      
+          - Family history of benign macrocephaly common
+          - Male infants, ± late to walk
+- ## Demographics
+  
+  
+    - Most common imaging diagnosis for macrocrania in patients < 1 year of age 
+          - Usually presents at 3-9 months
+    - Sex: M:F = 2:1
+- ## Natural History & Prognosis
+  
+  
+    - Enlarged SAS → ↑ suture/calvarial malleability/compliance → predisposes to posterior plagiocephaly
+    - Self-limited; resolves without therapy by 12-24 months
+          - Spontaneous resolution of spaces and symptoms
+    - Macrocephaly may persist
+- ## Treatment
+  
+  
+    - No treatment necessary
+    - Normal outcome (developmental delay usually resolves as prominent SAS resolves)
+
+# DIAGNOSTIC CHECKLIST
+
+- ## Image Interpretation Pearls
+  
+  
+    - Crucial to know HC
+    - Further evaluation with brain MR or CT if US atypical
+          - Moderate/large/complex subdural collection → NAT work-up
+          - Even small/simple subdural collections should be discussed with referring clinician to identify any concerns for NAT that merit further work-up
+
+ 17f5e314-01d9-44b0-81da-6468019ad492
+
+## References
+
+# Selected References
+
+1. [Yum SK et al: Enlarged subarachnoid space on cranial ultrasound in preterm infants: Neurodevelopmental implication. Sci Rep. 9(1):19072, 2019](http://www.ncbi.nlm.nih.gov/pubmed/?term=31836837%5Bpmid%5D)
+1. [Zahl SM et al: Clinical, radiological, and demographic details of benign external hydrocephalus: a population-based study. Pediatr Neurol. 96:53-7, 2019](http://www.ncbi.nlm.nih.gov/pubmed/?term=30808532%5Bpmid%5D)
+1. [Zahl SM et al: Quality of life and physician-reported developmental, cognitive, and social problems in children with benign external hydrocephalus-long-term follow-up. Childs Nerv Syst. 35(2):245-50, 2019](http://www.ncbi.nlm.nih.gov/pubmed/?term=30523438%5Bpmid%5D)
+1. [Hansen JB et al: Evaluations for abuse in young children with subdural hemorrhages: findings based on symptom severity and benign enlargement of the subarachnoid spaces. J Neurosurg Pediatr. 21(1):31-7, 2018](http://www.ncbi.nlm.nih.gov/pubmed/?term=29099352%5Bpmid%5D)
+1. [Haws ME et al: A retrospective analysis of the utility of head computed tomography and/or magnetic resonance imaging in the management of benign macrocrania. J Pediatr. 182:283-9.e1, 2017](http://www.ncbi.nlm.nih.gov/pubmed/?term=27989412%5Bpmid%5D)
+1. [Hussain ZB et al: Extra-axial cerebrospinal fluid spaces in children with benign external hydrocephalus: a case-control study. Neuroradiol J. 30(5):410-7, 2017](http://www.ncbi.nlm.nih.gov/pubmed/?term=28691570%5Bpmid%5D)
+1. [Naffaa L et al: The diagnostic yield of ultrasound of the head in healthy infants presenting with the clinical diagnosis of benign macrocrania. Clin Radiol. 72(1):94.e7-94.e11, 2017](http://www.ncbi.nlm.nih.gov/pubmed/?term=27756452%5Bpmid%5D)
+1. [Whitehead MT et al: Reduced subarachnoid fluid diffusion in enlarged subarachnoid spaces of infancy. Neuroradiol J. 30(5):418-24, 2017](http://www.ncbi.nlm.nih.gov/pubmed/?term=28195509%5Bpmid%5D)
+1. [Tucker J et al: Macrocephaly in infancy: benign enlargement of the subarachnoid spaces and subdural collections. J Neurosurg Pediatr. 1-5, 2016](http://www.ncbi.nlm.nih.gov/pubmed/?term=26942270%5Bpmid%5D)
+1. [Halevy A et al: Development of infants with idiopathic external hydrocephalus. J Child Neurol. 30(8):1044-7, 2015](http://www.ncbi.nlm.nih.gov/pubmed/?term=25348416%5Bpmid%5D)
+1. [Marino MA et al: Benign external hydrocephalus in infants. A single centre experience and literature review. Neuroradiol J. 27(2):245-50, 2014](http://www.ncbi.nlm.nih.gov/pubmed/?term=24750715%5Bpmid%5D)
+1. [Greiner MV et al: Prevalence of subdural collections in children with macrocrania. AJNR Am J Neuroradiol. 34(12):2373-8, 2013](http://www.ncbi.nlm.nih.gov/pubmed/?term=23868166%5Bpmid%5D)
+1. [Mattei TA et al: Benign extracerebral fluid collection in infancy as a risk factor for the development of de novo intracranial arachnoid cysts. J Neurosurg Pediatr. 12(6):555-64, 2013](http://www.ncbi.nlm.nih.gov/pubmed/?term=24093592%5Bpmid%5D)
+1. [Schulz M et al: Intracranial pressure measurement in infants presenting with progressive macrocephaly and enlarged subarachnoid spaces. Acta Neurochir Suppl. 114:261-6, 2012](http://www.ncbi.nlm.nih.gov/pubmed/?term=22327705%5Bpmid%5D)
+1. [Sun M et al: Diffusion tensor imaging findings in young children with benign external hydrocephalus differ from the normal population. Childs Nerv Syst. 28(2):199-208, 2012](http://www.ncbi.nlm.nih.gov/pubmed/?term=22167268%5Bpmid%5D)
+1. [Bateman GA et al: External hydrocephalus in infants: six cases with MR venogram and flow quantification correlation. Childs Nerv Syst. 27(12):2087-96, 2011](http://www.ncbi.nlm.nih.gov/pubmed/?term=21833725%5Bpmid%5D)
+1. [Yew AY et al: Long-term health status in benign external hydrocephalus. Pediatr Neurosurg. 47(1):1-6, 2011](http://www.ncbi.nlm.nih.gov/pubmed/?term=21778677%5Bpmid%5D)
+1. [Zahl SM et al: Benign external hydrocephalus: a review, with emphasis on management. Neurosurg Rev. 34(4):417-32, 2011](http://www.ncbi.nlm.nih.gov/pubmed/?term=21647596%5Bpmid%5D)
+1. [Fernando S et al: Neuroimaging of nonaccidental head trauma: pitfalls and controversies. Pediatr Radiol. 38(8):827-38, 2008](http://www.ncbi.nlm.nih.gov/pubmed/?term=18176805%5Bpmid%5D)
+1. [Hellbusch LC: Benign extracerebral fluid collections in infancy: clinical presentation and long-term follow-up. J Neurosurg. 107(2 Suppl):119-25, 2007](http://www.ncbi.nlm.nih.gov/pubmed/?term=18459883%5Bpmid%5D)
+1. [Paciorkowski AR et al: When is enlargement of the subarachnoid spaces not benign? A genetic perspective. Pediatr Neurol. 37(1):1-7, 2007](http://www.ncbi.nlm.nih.gov/pubmed/?term=17628215%5Bpmid%5D)
+1. [Muenchberger H et al: Idiopathic macrocephaly in the infant: long-term neurological and neuropsychological outcome. Childs Nerv Syst. 22(10):1242-8, 2006](http://www.ncbi.nlm.nih.gov/pubmed/?term=16544148%5Bpmid%5D)
+1. [Lam WW et al: Ultrasonographic measurement of subarachnoid space in normal infants and children. Pediatr Neurol. 25(5):380-4, 2001](http://www.ncbi.nlm.nih.gov/pubmed/?term=11744312%5Bpmid%5D)
+
+## Differential diagnosis
+
+### Cistern, Subarachnoid Space Normal Variant
+DDX:167a514e-0b18-4a16-9474-41a1d760607b
+
+### Subarachnoid Space Normal Variants
+DDX:558a9979-3a38-473f-a5f8-bf6b6d6538e2
+
+## Cases
+
+- {'cases': [{'authors': [{'key': 'e8af6d26-3aad-47c9-9083-5128aab09af2', 'value': 'Susan I. Blaser, MD, FRCPC'}], 'caseVersionId': 'bd82b696-6c64-439d-a4e9-417829b23517', 'description': 'T2W axial images (#1-4) demonstrate &quot;squaring&quot; of the forehead and prominent pericerebral spaces. Small linear flow voids (arrows #2-4) represent veins traversing the subarachnoid space. The CSF spaces are at their widest at approximately 7 months of life. This process has also been called benign macrocephaly of infancy, physiologic extraventricular obstructive hydrocephalus, and external hydrocephalus. It is self-limited, usually resolving without therapy by 1 to 2 years of age.', 'history': 'Presented with macrocrania and frontal bossing.', 'imagePoolId': 'fd5ba87e-b9d9-48f7-aa78-96eac3fc925e', 'name': 'Crossing vessels', 'teachingPoint': None, 'demographics': '7 Months old male'}, {'authors': [{'key': 'e8af6d26-3aad-47c9-9083-5128aab09af2', 'value': 'Susan I. Blaser, MD, FRCPC'}], 'caseVersionId': '9e524b89-ebd0-4d81-9776-61b08302b2ec', 'description': 'NECT (#1, 2) demonstrate marked enlargement of the frontal pericerebral CSF spaces (arrow). Without the use of IV contrast material, traversing venous structures cannot be assessed. Similar findings are seen on sagittal and axial T1WIs (#3, 4) and axial FLAIR (#5). Axial (#6, 7) and coronal (#8) T2W images, however, are extremely useful. The T2W images reveal fine linear flow-voids due to traversing veins (#6-8, curved arrows), confirming that these enlarged spaces are in fact the subarachnoid space. \n\nComment: Enlarged pericerebral spaces in infancy are often a transient and benign condition. They resolve between 8 and 12 months of age, usually when the infant is able to be in the upright position for longer periods of time. They are slower to resolve in late walkers. The traversing veins may bleed with trauma, simulating non-accidental injury. Sequential follow-up of head-circumference (tape-measure, not imaging) is suggested. Repeat imaging is suggested when the macrocrania rapidly progresses, or when there are neurological symptoms.', 'history': 'Typically present with macrocrania between the ages of 3 and 8 months of age.', 'imagePoolId': 'ad479e42-534c-4d0e-9c71-416160f544a5', 'name': 'Marked', 'teachingPoint': None, 'demographics': '8 Months old male'}], 'caseType': 'typical', 'name': 'TYPICAL'}
+- {'cases': [{'authors': [{'key': 'e8af6d26-3aad-47c9-9083-5128aab09af2', 'value': 'Susan I. Blaser, MD, FRCPC'}], 'caseVersionId': '94dfc51a-38fa-4d6c-98ea-9215b294dad3', 'description': 'Axial NECT reveals an asymmetric prominence of pericerebral spaces (arrow, #1). T2W images obtained 5 months later demonstrate persistence of the asymmetry (arrows, #2, 3). No membranes or unequal signal intensity are seen on FLAIR (#4). Enhancing veins traverse the dilated subarachnoid space (curved arrows, #5). Enlargement of the subarachnoid space is common during infancy; danger signs requiring imaging evaluation would include rapid enlargement of head circumference, marked prominence of subarachnoid space, increased intracranial pressure and persistence or onset after 1 year of age. Asymmetry is also concerning, raising the suspicion for underlying subdural collection in non-accidental trauma.', 'history': 'Presented with macrocrania and possible seizures.', 'imagePoolId': 'd78c443b-8aae-4312-ab47-bfae3322a312', 'name': 'Asymmetric', 'teachingPoint': None, 'demographics': '3 Months old male'}, {'authors': [{'key': 'e8af6d26-3aad-47c9-9083-5128aab09af2', 'value': 'Susan I. Blaser, MD, FRCPC'}, {'key': '5cff4116-3654-4b3a-bb75-5ebe0b8c9850', 'value': 'Anne G. Osborn, MD, FACR'}], 'caseVersionId': 'c76edba4-99cf-4471-99a3-e58bc8676bab', 'description': 'There is marked asymmetry of subarachnoid space enlargement (#1-8). After contrast administration, however, veins are seen to traverse the subarachnoid space (arrow, #5-8). Compression of the right posterior subarachnoid space by positional lambdoid flattening (open arrow, #1, 2, 4) and calvarial deformation accounts, in part, for the prominence of the contralateral spaces. Asymmetry is of concern and should prompt a search for an underlying subdural component or of underlying brain dysgenesis. In this child, however, traversing veins confirm involvement only of the subarachnoid space.', 'history': None, 'imagePoolId': '91d9adcc-19f5-46a3-b1c1-2ceff2c37812', 'name': 'Asymmetric', 'teachingPoint': None, 'demographics': '3 Months old male'}, {'authors': [{'key': 'e8af6d26-3aad-47c9-9083-5128aab09af2', 'value': 'Susan I. Blaser, MD, FRCPC'}], 'caseVersionId': 'ddc8c96d-0330-4a2a-8065-24b477e33f11', 'description': 'Enlarged pericerebral spaces are identified on coronal sonography. Distance between the surface of the brain and the dura is 1.5 cm, or 3 times the maximum allowable measurement of 5 mm. High-resolution view reveals multiple linear veins (arrows) traversing the subarachnoid space, confirming the diagnosis.  \n\nNECT demonstrates huge pericerebral spaces over the frontal convexities and widening the interhemispheric and Sylvian fissures. CECT confirms a plethora of veins (arrows) traversing the subarachnoid space. No subdural membrane is identified.\n\nEnlargement of the subarachnoid spaces, also known as physiologic extraventricular obstructive hydrocephalus (EVOH), external hydrocephalus or benign macrocephaly of infancy is usually a transient phenomenon peaking between 3 and 8 months of age. Surgical intervention is needed only when spaces reach massive size, as in this case.  \n\nBe careful not to mistake enlarged arachnoid spaces (in the presence of macrocephaly) for atrophy. Always determine and document the head circumference.', 'history': 'Patient was noted to have macrocephaly at 2 months of age. Subarachnoid spaces enlarged dramatically over time. Patient required shunt at 7 months.', 'imagePoolId': 'e88a10c0-feca-4740-8c77-7996345f28ae', 'name': 'Massive', 'teachingPoint': None, 'demographics': '7 Months old male'}], 'caseType': 'variant', 'name': 'VARIANT'}
+
+
+## Images
+
+
+### Selected Images
+
+![Axial graphic shows classic enlarged subarachnoid spaces (SAS) in a macrocephalic infant (head circumference &gt; 95%). Note the symmetric enlargement with idiopathic enlargement of SAS during the 1st year of life.](images/app.statdx.com_image_thumbnail_625c002a-cbdb-4b3b-82b8-c174380b8cab_annotated_true_size_900_quality_90_0217a31f_20251018T164822Z.jpg)
+*Axial graphic shows classic enlarged subarachnoid spaces (SAS) in a macrocephalic infant (head circumference &gt; 95%). Note the symmetric enlargement with idiopathic enlargement of SAS during the 1st year of life.*
+
+![Axial graphic shows classic enlarged subarachnoid spaces (SAS) in a macrocephalic infant (head circumference &gt; 95%). Note the symmetric enlargement with idiopathic enlargement of SAS during the 1st year of life.](images/app.statdx.com_image_thumbnail_625c002a-cbdb-4b3b-82b8-c174380b8cab_size_174_quality_85_c1b69f4c_20251018T164756Z.jpg)
+*Axial graphic shows classic enlarged subarachnoid spaces (SAS) in a macrocephalic infant (head circumference &gt; 95%). Note the symmetric enlargement with idiopathic enlargement of SAS during the 1st year of life.*
+
+![Axial T2 MR shows enlarged frontal &amp; anterior interhemispheric pericerebral fluid spaces <img src='/img/arrows/WC.png'/>, mild ventriculomegaly, &amp; right-sided posterior plagiocephaly <img src='/img/arrows/WS.png'/> in a 7-month-old boy with macrocephaly.](images/app.statdx.com_image_thumbnail_999bae79-c259-4e1e-99f7-df0f6d6080e6_annotated_true_size_900_quality_90_99a2989a_20251018T164822Z.jpg)
+*Axial T2 MR shows enlarged frontal &amp; anterior interhemispheric pericerebral fluid spaces <img src='/img/arrows/WC.png'/>, mild ventriculomegaly, &amp; right-sided posterior plagiocephaly <img src='/img/arrows/WS.png'/> in a 7-month-old boy with macrocephaly.*
+
+![Coronal US in a 7-month-old boy with macrocrania shows enlarged SAS  <img src='/img/arrows/WS.png'/> &amp; normal ventricular <img src='/img/arrows/CS.png'/> size. Note the normal size of the sulci. This is a typical clinical history &amp; imaging appearance for benign enlargement of the SAS.](images/app.statdx.com_image_thumbnail_e4adf66f-2a85-49d4-81d1-b5a27e609e47_annotated_true_size_900_quality_90_697cf19c_20251018T164822Z.jpg)
+*Coronal US in a 7-month-old boy with macrocrania shows enlarged SAS  <img src='/img/arrows/WS.png'/> &amp; normal ventricular <img src='/img/arrows/CS.png'/> size. Note the normal size of the sulci. This is a typical clinical history &amp; imaging appearance for benign enlargement of the SAS.*
+
+![Coronal color Doppler US in a 4-month-old girl shows vessels <img src='/img/arrows/WS.png'/> traversing the enlarged SAS <img src='/img/arrows/CS.png'/>. Doppler US can be helpful to exclude subdural collections by demonstrating normal veins in the SAS.](images/app.statdx.com_image_thumbnail_2378a15b-8f1c-47cf-bf91-5ab9181ca721_annotated_true_size_900_quality_90_ad41edb4_20251018T164822Z.jpg)
+*Coronal color Doppler US in a 4-month-old girl shows vessels <img src='/img/arrows/WS.png'/> traversing the enlarged SAS <img src='/img/arrows/CS.png'/>. Doppler US can be helpful to exclude subdural collections by demonstrating normal veins in the SAS.*
+
+![Coronal US in a 3 month old with macrocephaly shows prominent SAS <img src='/img/arrows/CO.png'/> as well as mild enlargement of the lateral ventricles <img src='/img/arrows/CS.png'/>. Mild lateral ventricular enlargement is common in benign enlargement of subarachnoid spaces (BESSI).](images/app.statdx.com_image_thumbnail_7ed3d5fd-ca66-4f3f-b16a-def63fa152be_annotated_true_size_900_quality_90_0bbc9592_20251018T164822Z.jpg)
+*Coronal US in a 3 month old with macrocephaly shows prominent SAS <img src='/img/arrows/CO.png'/> as well as mild enlargement of the lateral ventricles <img src='/img/arrows/CS.png'/>. Mild lateral ventricular enlargement is common in benign enlargement of subarachnoid spaces (BESSI).*
+
+![Coronal T2 MR in a 6 month old with macrocephaly shows symmetrically prominent bifrontal SAS <img src='/img/arrows/CO.png'/> with mild enlargement of the lateral ventricles <img src='/img/arrows/CS.png'/>. Mild enlargement of the lateral ventricles should not dissuade one from suggesting BESSI.](images/app.statdx.com_image_thumbnail_82a63fe6-8800-487d-a506-2f4b3399fd2d_annotated_true_size_900_quality_90_fef6728f_20251018T164822Z.jpg)
+*Coronal T2 MR in a 6 month old with macrocephaly shows symmetrically prominent bifrontal SAS <img src='/img/arrows/CO.png'/> with mild enlargement of the lateral ventricles <img src='/img/arrows/CS.png'/>. Mild enlargement of the lateral ventricles should not dissuade one from suggesting BESSI.*
+
+![Coronal T2 MR at 13 months (left) &amp; NECT at 5 years (right) of age show expected resolution of the enlarged SAS <img src='/img/arrows/CS.png'/> over a 4-year period. Enlarged SAS typically resolve by 24 months of age.](images/app.statdx.com_image_thumbnail_6d4772cf-8e5a-46f7-b768-d7df54bae831_annotated_true_size_900_quality_90_1842bb3c_20251018T164822Z.jpg)
+*Coronal T2 MR at 13 months (left) &amp; NECT at 5 years (right) of age show expected resolution of the enlarged SAS <img src='/img/arrows/CS.png'/> over a 4-year period. Enlarged SAS typically resolve by 24 months of age.*
+
+![Coronal high-resolution US in a 4-month-old girl with macrocrania shows bilateral enlargement of the SAS <img src='/img/arrows/CS.png'/>. Also present are small, bilateral, subdural collections <img src='/img/arrows/WS.png'/>, which are anechoic compared to the SAS. Note the separation of the arachnoid membrane <img src='/img/arrows/CO.png'/>.](images/app.statdx.com_image_thumbnail_e1ad2f29-ee6d-4acb-9009-60ab93f84ebb_annotated_true_size_900_quality_90_5094ced0_20251018T164822Z.jpg)
+*Coronal high-resolution US in a 4-month-old girl with macrocrania shows bilateral enlargement of the SAS <img src='/img/arrows/CS.png'/>. Also present are small, bilateral, subdural collections <img src='/img/arrows/WS.png'/>, which are anechoic compared to the SAS. Note the separation of the arachnoid membrane <img src='/img/arrows/CO.png'/>.*
+
+![Axial PD MR in a 4-month-old girl with macrocrania shows enlarged SAS <img src='/img/arrows/CS.png'/>, which are isointense to the brain. Also note the small, bilateral, nonhemorrhagic, hyperintense subdural fluid collections <img src='/img/arrows/WS.png'/>.](images/app.statdx.com_image_thumbnail_c10a685b-5eda-415a-a0a7-c9ba71989dbc_annotated_true_size_900_quality_90_5ff1fb6d_20251018T164822Z.jpg)
+*Axial PD MR in a 4-month-old girl with macrocrania shows enlarged SAS <img src='/img/arrows/CS.png'/>, which are isointense to the brain. Also note the small, bilateral, nonhemorrhagic, hyperintense subdural fluid collections <img src='/img/arrows/WS.png'/>.*
+
+![Coronal T2 MR in the same patient shows symmetrically enlarged SAS <img src='/img/arrows/CS.png'/> as well as small, bilateral, nonhemorrhagic subdural fluid collections <img src='/img/arrows/WC.png'/>. Small, subdural fluid collections are seen in ~ 4% of patients with enlarged SAS.](images/app.statdx.com_image_thumbnail_dadaa55c-ec98-4fde-8e1a-f4ff02313e31_annotated_true_size_900_quality_90_8c00f0a2_20251018T164802Z.jpg)
+*Coronal T2 MR in the same patient shows symmetrically enlarged SAS <img src='/img/arrows/CS.png'/> as well as small, bilateral, nonhemorrhagic subdural fluid collections <img src='/img/arrows/WC.png'/>. Small, subdural fluid collections are seen in ~ 4% of patients with enlarged SAS.*
+
+
+### Additional Images
+
+![Axial graphic shows classic enlargement of the subarachnoid spaces (SAS) in a macrocephalic infant. There is symmetric bifrontal enlargement of the SAS, which contain multiple bridging veins <img src='/img/arrows/WS.png'/>. Mild ventriculomegaly is present.](images/app.statdx.com_image_thumbnail_970df207-9c92-40e4-83d2-71d303b99906_annotated_true_size_900_quality_90_013d624a_20251018T164803Z.jpg)
+*Axial graphic shows classic enlargement of the subarachnoid spaces (SAS) in a macrocephalic infant. There is symmetric bifrontal enlargement of the SAS, which contain multiple bridging veins <img src='/img/arrows/WS.png'/>. Mild ventriculomegaly is present.*
+
+![Axial T2 MR in a 6-month-old boy with enlarged SAS shows vessels <img src='/img/arrows/CS.png'/> coursing through the SAS. Note the lack of mass effect on the underlying brain parenchyma. There is mild enlargement of the lateral ventricles <img src='/img/arrows/WS.png'/>, a common finding in benign enlargement of the SAS.](images/app.statdx.com_image_thumbnail_853ffc4b-e3ff-4876-a50a-9fd8233de3af_annotated_true_size_900_quality_90_7726ca40_20251018T164803Z.jpg)
+*Axial T2 MR in a 6-month-old boy with enlarged SAS shows vessels <img src='/img/arrows/CS.png'/> coursing through the SAS. Note the lack of mass effect on the underlying brain parenchyma. There is mild enlargement of the lateral ventricles <img src='/img/arrows/WS.png'/>, a common finding in benign enlargement of the SAS.*
+
+![Coronal T2 MR in the same 4-month-old girl with macrocrania shows symmetrically enlarged SAS <img src='/img/arrows/CS.png'/>  as well as small to moderate, bilateral subdural fluid collections <img src='/img/arrows/WC.png'/>. The subdural collections are slightly hyperintense to the SAS. Small subdural fluid collections are seen in ~ 4% of patients with enlarged SAS.](images/app.statdx.com_image_thumbnail_954b835b-dd1b-4ebc-922e-0e238b1c9468_annotated_true_size_900_quality_90_d9a0b852_20251018T164803Z.jpg)
+*Coronal T2 MR in the same 4-month-old girl with macrocrania shows symmetrically enlarged SAS <img src='/img/arrows/CS.png'/>  as well as small to moderate, bilateral subdural fluid collections <img src='/img/arrows/WC.png'/>. The subdural collections are slightly hyperintense to the SAS. Small subdural fluid collections are seen in ~ 4% of patients with enlarged SAS.*
+
+![Axial CECT shows enlarged SAS with enhancing traversing veins <img src='/img/arrows/WS.png'/> in a macrocephalic infant. This benign condition usually peaks at 7 months of age &amp; resolves spontaneously by 12-24 months of age.](images/app.statdx.com_image_thumbnail_6853ee67-afda-4c9b-86f1-275ecc5b5521_annotated_true_size_900_quality_90_9bff7ce2_20251018T164803Z.jpg)
+*Axial CECT shows enlarged SAS with enhancing traversing veins <img src='/img/arrows/WS.png'/> in a macrocephalic infant. This benign condition usually peaks at 7 months of age &amp; resolves spontaneously by 12-24 months of age.*
+
+![Axial T2 MR shows prominent frontal CSF spaces (craniocortical &amp; interhemispheric) with mildly prominent ventricles in this macrocephalic infant. Note the squaring of the forehead, seen clinically as &quot;frontal bossing.&quot; About 20-50% of cases have mild developmental delay (motor &gt; &gt; language), which nearly always resolves without therapy.](images/app.statdx.com_image_thumbnail_e08c6654-1cb2-4a96-bab2-26736e44e4d7_annotated_true_size_900_quality_90_85e3f2a6_20251018T164803Z.jpg)
+*Axial T2 MR shows prominent frontal CSF spaces (craniocortical &amp; interhemispheric) with mildly prominent ventricles in this macrocephalic infant. Note the squaring of the forehead, seen clinically as &quot;frontal bossing.&quot; About 20-50% of cases have mild developmental delay (motor &gt; &gt; language), which nearly always resolves without therapy.*
+
+![Axial NECT shows classic enlargement of SAS in this macrocephalic 5-month-old patient. Note the &gt; 5-mm widening of the bifrontal craniocortical &amp; anterior interhemispheric SAS.](images/app.statdx.com_image_thumbnail_d638e4e6-f964-4d41-808f-5de842763d53_annotated_true_size_900_quality_90_8f53a129_20251018T164803Z.jpg)
+*Axial NECT shows classic enlargement of SAS in this macrocephalic 5-month-old patient. Note the &gt; 5-mm widening of the bifrontal craniocortical &amp; anterior interhemispheric SAS.*
+
+![Axial CECT shows veins <img src='/img/arrows/WS.png'/> traversing the enlarged SAS.](images/app.statdx.com_image_thumbnail_d39a9497-890e-46b1-96c0-be6b83826f7c_annotated_true_size_900_quality_90_c8e6f3da_20251018T164803Z.jpg)
+*Axial CECT shows veins <img src='/img/arrows/WS.png'/> traversing the enlarged SAS.*
+
+![Axial T2 MR shows veins, represented by linear flow voids <img src='/img/arrows/WS.png'/>, traversing the enlarged SAS.](images/app.statdx.com_image_thumbnail_227b79c7-dac6-4e19-b936-bb18a562b566_annotated_true_size_900_quality_90_750c0054_20251018T164804Z.jpg)
+*Axial T2 MR shows veins, represented by linear flow voids <img src='/img/arrows/WS.png'/>, traversing the enlarged SAS.*
+
+![Coronal US shows dilated craniocortical SAS (note the space between the 2 markers) with veins <img src='/img/arrows/WS.png'/> traversing the SAS.](8b6b881a-7f98-409c-bb74-a593ce3bcc3c)
+*Coronal US shows dilated craniocortical SAS (note the space between the 2 markers) with veins <img src='/img/arrows/WS.png'/> traversing the SAS.*
+
+![Coronal T2 MR shows markedly enlarged SAS with prominent ventricles &amp; traversing bridging veins <img src='/img/arrows/BC.png'/>. Tiny, bilateral subdural collections are present <img src='/img/arrows/CS.png'/>.](82b8f025-0258-42d9-992c-faa46158c0e2)
+*Coronal T2 MR shows markedly enlarged SAS with prominent ventricles &amp; traversing bridging veins <img src='/img/arrows/BC.png'/>. Tiny, bilateral subdural collections are present <img src='/img/arrows/CS.png'/>.*
+

docs_md/articles/cavum-septi-pellucidi-csp_02127bd4-1efa-4056-925e-f1a1bbadf154.md

@@ -0,0 +1,319 @@
+---
+title: "Cavum Septi Pellucidi (CSP)"
+docid: "02127bd4-1efa-4056-925e-f1a1bbadf154"
+authors:
+  - key: "a25c450b-3d34-4f64-bba3-cc0834813df6"
+    value: "Miral D. Jhaveri, MD, MBA"
+  - key: "5cff4116-3654-4b3a-bb75-5ebe0b8c9850"
+    value: "Anne G. Osborn, MD, FACR"
+breadcrumbs:
+  -
+    name: "Brain"
+    slug: "brain"
+    treeNodeId: "6d8829f1-14d7-45af-8675-255189aa526a"
+  -
+    name: "Diagnosis"
+    slug: "diagnosis"
+    treeNodeId: "51c00394-446e-4a38-94af-d3b1d14d34e8"
+  -
+    name: "Anatomy-Based Diagnoses"
+    slug: "anatomy-based-diagnoses"
+    treeNodeId: "529d3e33-f508-498c-bc70-cf962e81e629"
+  -
+    name: "Ventricles and Cisterns"
+    slug: "ventricles-and-cisterns"
+    treeNodeId: "33b267f0-908c-4c77-81f8-f6135d1bc592"
+  -
+    name: "Normal Variants"
+    slug: "normal-variants"
+    treeNodeId: "bf92256f-cdff-4bcd-8420-d876b9e4031a"
+  -
+    name: "Cavum Septi Pellucidi (CSP)"
+    slug: "cavum-septi-pellucidi-csp"
+    treeNodeId: null
+category: "Brain"
+documentVersionId: "1d576faa-488e-43a7-b6d4-2479d199a187"
+imageCount: 11
+lastUpdated: "05/08/20"
+pageDescription: "Cavum Septi Pellucidi (CSP)"
+pageKeywords: "Brain, Diagnosis, Anatomy-Based Diagnoses, Ventricles and Cisterns, Normal Variants, Cavum Septi Pellucidi (CSP)"
+pageTitle: "Cavum Septi Pellucidi (CSP) | STATdx"
+enhancedTitle: "Cavum Septi Pellucidi (CSP)"
+type: "DX"
+references: true
+cases: 2
+breadcrumbs:
+  - "Brain"
+  - "Diagnosis"
+  - "Anatomy-Based Diagnoses"
+  - "Ventricles and Cisterns"
+  - "Normal Variants"
+  - "Cavum Septi Pellucidi (CSP)"
+---
+# KEY FACTS
+
+- ## Terminology
+  
+  
+    - Cystic CSF cavity of septum pellucidum (SP)
+          - Occurs ± cavum vergae (CV)
+- ## Imaging
+  
+  
+    - Elongated finger-shaped CSF collection between lateral ventricles
+          - Cavum septi pellucidi (CSP): Between frontal horns of lateral ventricles
+          - CV: Posterior extension between fornices
+    - Size varies from slit like to several mm, occasionally > 1 cm
+    - SP invariably cystic in fetus
+          - Width of fetal CSP increases between 19-27 weeks
+          - Plateaus at 28 weeks
+          - Gradually closes in rostral direction between 28 weeks and term
+          - CSP present in 100% of premature, 85% of term infants
+    - CSP seen in up to 15-20% of adults
+- ## Top Differential Diagnoses
+  
+  
+    - Asymmetric lateral ventricles
+    - Cavum velum interpositum
+    - Ependymal cyst
+    - Absent SP
+- ## Pathology
+  
+  
+    - CSP forms if fetal SP fails to obliterate
+    - Precise etiology of fluid accumulation unknown
+    - CSP is not "5th ventricle"
+    - CV is not "6th ventricle"
+- ## Clinical Issues
+  
+  
+    - Usually asymptomatic, incidental
+    - Headache (relationship to cyst unclear)
+    - CSP frequent among athletes with history of repeated traumatic brain injury, such as boxers
+- ## Diagnostic Checklist
+  
+  
+    - CV almost never occurs without CSP
+
+# TERMINOLOGY
+
+- ## Abbreviations
+  
+  
+    - Cavum septi pellucidi (CSP)
+    - Cavum vergae (CV)
+- ## Definitions
+  
+  
+    - Cystic CSF cavity of septum pellucidum (CSP) ± posterior continuation (CV)
+
+# IMAGING
+
+- ## General Features
+  
+  
+    - ### Best diagnostic clue
+      
+      
+          - Elongated finger-shaped CSF collection between lateral ventricles
+    - ### Location
+      
+      
+          - CSP: Between frontal horns of lateral ventricles
+          - CV: Posterior extension between fornices
+    - ### Size
+      
+      
+          - From slit-like to several mm, occasionally > 1 cm
+    - ### Morphology
+      
+      
+          - Elongated, finger like
+- ## CT Findings
+  
+  
+    - ### NECT
+      
+      
+          - CSF collection in septum pellucidum
+    - ### CECT
+      
+      
+          - Does not enhance
+- ## MR Findings
+  
+  
+    - ### T1WI
+      
+      
+          - Axial: Finger-like CSF space between lateral ventricles
+          - Sagittal: Extends posteriorly from rostrum to splenium of corpus callosum (CC) above, ICVs below
+    - ### T2WI
+      
+      
+          - Isointense with CSF
+    - ### FLAIR
+      
+      
+          - Suppresses completely
+    - ### DWI
+      
+      
+          - Does not restrict
+- ## Ultrasonographic Findings
+  
+  
+    - ### Grayscale ultrasound
+      
+      
+          - Septum pellucidum invariably present in normal fetus
+                  - Width of fetal CSP increases between 19-27 weeks
+                  - Plateaus, then gradually closes in rostral direction between 28 weeks and term
+                  - Inability to find CSP on fetal US requires search for CC
+
+# DIFFERENTIAL DIAGNOSIS
+
+- [Asymmetric Lateral Ventricles](/document/arachnoid-cyst/7d63f0d3-6999-4d8c-a41d-953f738c43a6)
+    - Septum pellucidum bowed but intact
+- [Cavum Velum Interpositum](/document/arachnoid-cyst/7d63f0d3-6999-4d8c-a41d-953f738c43a6)
+    - Triangular shaped; no extension anterior to foramen of Monro
+- [Ependymal Cyst](/document/ependymal-cyst/910da375-2150-49b5-8e0c-bc93487239d1)
+    - In body/atrium of lateral ventricle
+- [Septooptic Dysplasia](/document/septo-optic-dysplasia/df4653b9-6e80-4f77-b737-29280f00d1ad)
+    - SP absent, "squared off" frontal horns
+
+# PATHOLOGY
+
+- ## General Features
+  
+  
+    - ### Etiology
+      
+      
+          - CSP forms if fetal septum pellucidum fails to obliterate
+          - Precise etiology of fluid accumulation unknown
+          - CSP is not "5th ventricle," nor is CV "6th ventricle"
+    - ### Associated abnormalities
+      
+      
+          - Rare: Hydrocephalus
+- ## Staging, Grading, & Classification
+  
+  
+    - Shaw and Ellsworth classification for CSP, CV
+          - Asymptomatic, incidental cavum (communicating or not)
+          - Symptomatic, pathological, noncommunicating cavum
+                  - Simple and uncomplicated
+                  - Complicated by other lesions
+
+# CLINICAL ISSUES
+
+- ## Presentation
+  
+  
+    - ### Most common signs/symptoms
+      
+      
+          - Usually asymptomatic, incidental
+                  - May remain asymptomatic even if mass effect present
+          - Headache (relationship to cyst unclear)
+- ## Demographics
+  
+  
+    - ### Age
+      
+      
+          - CSP
+                  - Present in 100% of premature, 85% of term infants
+                  - From 1% up to 15-20% of adults
+          - CV
+                  - 100% at fetal age of 6 months, 30% at term
+                  - < 1% of adults
+- ## Natural History & Prognosis
+  
+  
+    - Normally regresses
+          - May persist as normal variant
+    - Rare: Enlarges, may cause mass effect
+- ## Treatment
+  
+  
+    - Usually none
+
+# DIAGNOSTIC CHECKLIST
+
+- ## Image Interpretation Pearls
+  
+  
+    - CV almost never occurs without CSP
+
+ 1f464af2-e137-4e40-827c-7f61f0623628
+
+## References
+
+# Selected References
+
+1. [Krejčí T et al: Symptomatic cysts of the cavum septi pellucidi, cavum vergae and cavum veli interpositi: A retrospective duocentric study of 10 patients. Clin Neurol Neurosurg. 185:105494, 2019](http://www.ncbi.nlm.nih.gov/pubmed/?term=31472394%5Bpmid%5D)
+1. [Lee JK et al: Association of cavum septum pellucidum and cavum vergae with cognition, mood, and brain volumes in professional fighters. JAMA Neurol. ePub, 2019](http://www.ncbi.nlm.nih.gov/pubmed/?term=31498371%5Bpmid%5D)
+1. [M Das J et al: Cavum septum pellucidum 2019](http://www.ncbi.nlm.nih.gov/pubmed/?term=30725733%5Bpmid%5D)
+1. [Nagaraj UD et al: Abnormalities associated with the cavum septi pellucidi on fetal MRI: What radiologists need to know. AJR Am J Roentgenol. 210(5):989-97, 2018](http://www.ncbi.nlm.nih.gov/pubmed/?term=29489402%5Bpmid%5D)
+1. [Tsutsumi S et al: Visualization of the cavum septi pellucidi, cavum Vergae, and cavum veli interpositi using magnetic resonance imaging. Surg Radiol Anat. 40(2):159-64, 2018](http://www.ncbi.nlm.nih.gov/pubmed/?term=29094193%5Bpmid%5D)
+1. [Gardner RC et al: Cavum septum pellucidum in retired American pro-football players. J Neurotrauma. ePub, 2015](http://www.ncbi.nlm.nih.gov/pubmed/?term=25970145%5Bpmid%5D)
+1. [Toivonen P et al: Cavum septum pellucidum and psychopathy. Br J Psychiatry. 203(2):152-3, 2013](http://www.ncbi.nlm.nih.gov/pubmed/?term=23908342%5Bpmid%5D)
+1. [Santo S et al: Counseling in fetal medicine: agenesis of the corpus callosum. Ultrasound Obstet Gynecol. 40(5):513-21, 2012](http://www.ncbi.nlm.nih.gov/pubmed/?term=23024003%5Bpmid%5D)
+1. [Winter TC et al: The cavum septi pellucidi: why is it important? J Ultrasound Med. 29(3):427-44, 2010](http://www.ncbi.nlm.nih.gov/pubmed/?term=20194938%5Bpmid%5D)
+1. [Callen PW et al: Columns of the fornix, not to be mistaken for the cavum septi pellucidi on prenatal sonography. J Ultrasound Med. 27(1):25-31, 2008](http://www.ncbi.nlm.nih.gov/pubmed/?term=18096727%5Bpmid%5D)
+1. [Takahashi T et al: Prevalence of large cavum septi pellucidi in ultra high-risk individuals and patients with psychotic disorders. Schizophr Res. 105(1-3):236-44, 2008](http://www.ncbi.nlm.nih.gov/pubmed/?term=18693084%5Bpmid%5D)
+1. [Needelman H et al: Postterm closure of the cavum septi pellucidi and developmental outcome in premature infants. J Child Neurol. 22(3):314-6, 2007](http://www.ncbi.nlm.nih.gov/pubmed/?term=17621502%5Bpmid%5D)
+1. [Sencer A et al: Cerebrospinal fluid dynamics of the cava septi pellucidi and vergae. Case report. J Neurosurg. 94(1):127-9, 2001](http://www.ncbi.nlm.nih.gov/pubmed/?term=11147881%5Bpmid%5D)
+
+## Cases
+
+- {'cases': [{'authors': [{'key': '5cff4116-3654-4b3a-bb75-5ebe0b8c9850', 'value': 'Anne G. Osborn, MD, FACR'}], 'caseVersionId': '66e58cd7-5239-4b71-8bd5-88312583a976', 'description': 'Axial (image 1) and sagittal (image 2) T1WIs show classic cavum septi pellucidi (CSP) and Vergae. The CSP lies in between the frontal horns of the lateral ventricles (open arrows) and the cavum Vergae (CV) (curved arrows) extends posteriorly in between the bodies of the lateral ventricles. The CSP + CV form a &quot;cigar-shaped&quot; CSF-containing structure that lies between the lateral ventricles. Note that on the sagittal view, the cavum occupies the entire space under the corpus callosum, flattening the fornix (arrows). This contrasts with cavum velum interpositum, which usually displaces the fornix anterosuperiorly.', 'history': 'Middle-aged patient with headaches, no neurologic findings.', 'imagePoolId': 'fbd519fb-6ab7-498c-8474-51dbaa25dd2b', 'name': 'With cavum vergae', 'teachingPoint': None}, {'authors': [{'key': '5cff4116-3654-4b3a-bb75-5ebe0b8c9850', 'value': 'Anne G. Osborn, MD, FACR'}], 'caseVersionId': '15afabe5-824c-46be-9f9b-58cded699493', 'description': 'Axial T1-weighted MR scans show the classic appearance of cavum septi pellucidi (arrows) with posterior extension into a cavum Vergae (open arrows), seen here as a CSF-signal collection that lies between the bodies of the lateral ventricles.', 'history': 'Asymptomatic patient, incidental finding.', 'imagePoolId': '8d51f828-9478-4e8d-945d-09d8496552d5', 'name': 'CSP, vergae', 'teachingPoint': None}, {'authors': [{'key': '5cff4116-3654-4b3a-bb75-5ebe0b8c9850', 'value': 'Anne G. Osborn, MD, FACR'}], 'caseVersionId': 'c38954f4-6732-402d-ad20-5bf751eefb80', 'description': 'Sagittal T1-weighted MR scan (#1) shows the classic finding of a cavum septi pellucidi (CSP), seen here as a CSF-filled collection under the corpus callosum (open arrows) that flattens and displaces the thinned fornix (arrows).  Axial image (#2) and coronal image (#3) T2WIs show the mass follows CSF in signal intensity.  On the coronal scan, the thinned fornices (arrows) are barely visible.  Coronal FLAIR scan (#4) shows the rounded contours of the CSP.  Fluid in the CSP suppresses completely on FLAIR.', 'history': None, 'imagePoolId': 'ae79975a-0e41-4b33-ad5f-5a209538cd81', 'name': 'CSP cyst, fornix dysplasia', 'teachingPoint': None}], 'caseType': 'typical', 'name': 'TYPICAL'}
+- {'cases': [{'authors': [{'key': '5cff4116-3654-4b3a-bb75-5ebe0b8c9850', 'value': 'Anne G. Osborn, MD, FACR'}], 'caseVersionId': 'ce9dcc88-81a6-4e2b-b127-03d2d2cbefe8', 'description': 'Axial NECT scans (#1, 2) show a rounded CSF-density mass in the septum pellucidum that is contiguous with an elongated CSF mass lying in-between the bodies of the lateral ventricles (arrows). This is a cavum septi pellucidi with cavum Vergae. Contrast-enhanced scans (source images from the CTA performed in this patient) show no enhancement (#3-5).  \n\nThis case is a slight variant on the typical CSP + Vergae as it is somewhat rounder than usually seen. This is considered a normal variant.', 'history': 'Incidental finding.', 'imagePoolId': 'b7937706-cf34-4252-a8e0-4e96b937e7c9', 'name': 'Very round', 'teachingPoint': None, 'demographics': '30 Years old male'}, {'authors': [{'key': '5cff4116-3654-4b3a-bb75-5ebe0b8c9850', 'value': 'Anne G. Osborn, MD, FACR'}, {'key': '789e84ce-9fde-4452-b27a-21d45423ac32', 'value': 'Anne  Kennedy, MD, FSRU, FAIUM'}], 'caseVersionId': 'a5a4b3e1-aaa0-4d47-ae95-c458d17afb1f', 'description': 'Fetal MR (#1) and ultrasound (# 2) show absent septum pellucidum in corpus callosum agenesis.  Note &quot;Viking helmet&quot; appearance on the coronal T2WI through the frontal and temporal horns (#1), with widely spaced parallel lateral ventricles and a high-riding third ventricle that is continuous superiorly with the interhemispheric fissure.  Colpocephaly (enlarged occipital horns) is common in callosal agenesis and is seen on image #2 (arrow).', 'history': 'Routine prenatal imaging.', 'imagePoolId': '53203fa9-945d-44e0-8723-bab3d8cf207c', 'name': 'Absent CSP, CC agenesis', 'teachingPoint': None}, {'authors': [{'key': '5cff4116-3654-4b3a-bb75-5ebe0b8c9850', 'value': 'Anne G. Osborn, MD, FACR'}], 'caseVersionId': 'b793cb29-03cb-45cd-a54d-1805f7544044', 'description': 'A classic cavum septi pellucidi (CSP) with cavum Vergae (CV) is seen (arrows). This case is unusual because the CSP and CV are very small.', 'history': 'Incidental finding. Patient being imaged for possible intracranial metastases.', 'imagePoolId': '77f1b3ce-a427-4b7e-b075-8278f3c4e3ce', 'name': 'Very small', 'teachingPoint': None}, {'authors': [{'key': '5cff4116-3654-4b3a-bb75-5ebe0b8c9850', 'value': 'Anne G. Osborn, MD, FACR'}], 'caseVersionId': 'ede02258-1779-427d-9e2e-f9aeb96dfac9', 'description': 'An unusually large cavum septi pellucidi with cavum Vergae is present. Note mass effect with lateral bowing of the leaves of the septum pellucidum on the coronal scans (#3-4, arrows). Lateral/inferior displacement of the internal cerebral veins on the sagittal image (#1, open arrows) and coronal views (#3-4) (#3, open arrows) is seen. Axial scan (#2) shows lateral bowing of the fornices posteriorly (arrows). Image 4 also shows lateral displacement of the foramen of Monro (curved arrows). No obstructive hydrocephalus is present.', 'history': 'Asymptomatic patient, incidental finding.', 'imagePoolId': '80daa008-e840-43a4-82e4-b9d25b8696f1', 'name': 'Large with mass effect', 'teachingPoint': None, 'demographics': '20 Years old female'}], 'caseType': 'variant', 'name': 'VARIANT'}
+
+
+## Images
+
+
+### Selected Images
+
+![Coronal graphic with axial insert shows classic cavum septi pellucidi (CSP) with cavum vergae (CV) <img src='/img/arrows/CO.png'/>. Note the finger-like CSF collection between the lateral ventricles.](images/app.statdx.com_image_thumbnail_1fb3ac06-849c-4812-b789-388045765af2_annotated_true_size_900_quality_90_99777374_20251018T164843Z.jpg)
+*Coronal graphic with axial insert shows classic cavum septi pellucidi (CSP) with cavum vergae (CV) <img src='/img/arrows/CO.png'/>. Note the finger-like CSF collection between the lateral ventricles.*
+
+![Coronal graphic with axial insert shows classic cavum septi pellucidi (CSP) with cavum vergae (CV) <img src='/img/arrows/CO.png'/>. Note the finger-like CSF collection between the lateral ventricles.](images/app.statdx.com_image_thumbnail_1fb3ac06-849c-4812-b789-388045765af2_size_174_quality_85_bf1f1833_20251018T164756Z.jpg)
+*Coronal graphic with axial insert shows classic cavum septi pellucidi (CSP) with cavum vergae (CV) <img src='/img/arrows/CO.png'/>. Note the finger-like CSF collection between the lateral ventricles.*
+
+![Coronal T1 C+ SPGR MR shows a classic large CSP between the frontal horns <img src='/img/arrows/CS.png'/>. There is lateral bowing of the leaves of the septum pellucidum <img src='/img/arrows/CC.png'/>.](images/app.statdx.com_image_thumbnail_977baa81-1d68-456f-b6bc-4f9d4aceed84_annotated_true_size_900_quality_90_a6318635_20251018T164843Z.jpg)
+*Coronal T1 C+ SPGR MR shows a classic large CSP between the frontal horns <img src='/img/arrows/CS.png'/>. There is lateral bowing of the leaves of the septum pellucidum <img src='/img/arrows/CC.png'/>.*
+
+![Axial T2 MR shows cavum septi pellucidi between the leaves of the septum pellucidum <img src='/img/arrows/CO.png'/>. Although seen incidentally, some studies have reported that CSP is frequent among athletes with a history of repeated traumatic brain injury (TBI), such as boxers and American professional football players.](images/app.statdx.com_image_thumbnail_a03300a7-6e69-481b-9a3b-1537f7202ca1_annotated_true_size_900_quality_90_9abe7b83_20251018T164843Z.jpg)
+*Axial T2 MR shows cavum septi pellucidi between the leaves of the septum pellucidum <img src='/img/arrows/CO.png'/>. Although seen incidentally, some studies have reported that CSP is frequent among athletes with a history of repeated traumatic brain injury (TBI), such as boxers and American professional football players.*
+
+![Axial FLAIR MR shows a large CSP with CV as a large CSF collection between the leaves of the septum pellucidum <img src='/img/arrows/CS.png'/> continuing directly posteriorly with the CSF collection, splaying the fornices laterally <img src='/img/arrows/CC.png'/>.](images/app.statdx.com_image_thumbnail_9995e3f8-eb09-40bd-8ff6-c7065bb93d40_annotated_true_size_900_quality_90_fbf42288_20251018T164843Z.jpg)
+*Axial FLAIR MR shows a large CSP with CV as a large CSF collection between the leaves of the septum pellucidum <img src='/img/arrows/CS.png'/> continuing directly posteriorly with the CSF collection, splaying the fornices laterally <img src='/img/arrows/CC.png'/>.*
+
+
+### Additional Images
+
+![Axial NECT shows a variant of cavum septi pellucidi. Here, the CSP appears almost round <img src='/img/arrows/CS.png'/>.](images/app.statdx.com_image_thumbnail_4dd3811b-29d3-488c-bdd1-f8a58e630508_annotated_true_size_900_quality_90_d1b1d220_20251018T164843Z.jpg)
+*Axial NECT shows a variant of cavum septi pellucidi. Here, the CSP appears almost round <img src='/img/arrows/CS.png'/>.*
+
+![Sagittal T1 C+ MR shows a large CSP/CV that extends from just behind the corpus callosum genu all the way posteriorly to the splenium. The fornices are not visible, and the internal cerebral vein is flattened <img src='/img/arrows/CS.png'/>.](images/app.statdx.com_image_thumbnail_effbc5cf-b18b-47ed-917e-e16bceb020a6_annotated_true_size_900_quality_90_440f151e_20251018T164843Z.jpg)
+*Sagittal T1 C+ MR shows a large CSP/CV that extends from just behind the corpus callosum genu all the way posteriorly to the splenium. The fornices are not visible, and the internal cerebral vein is flattened <img src='/img/arrows/CS.png'/>.*
+
+![Coronal T1 C+ MR in the same patient shows the large CSP bowing the leaves of the septum pellucidum laterally <img src='/img/arrows/CS.png'/>.](images/app.statdx.com_image_thumbnail_86ce8855-4e01-4fd1-bd27-4ddfdd11bea3_annotated_true_size_900_quality_90_96ab0ca1_20251018T164843Z.jpg)
+*Coronal T1 C+ MR in the same patient shows the large CSP bowing the leaves of the septum pellucidum laterally <img src='/img/arrows/CS.png'/>.*
+
+![Axial T1 MR shows a small cavum septi pellucidi with cavum vergae <img src='/img/arrows/CS.png'/>. Note the finger-like appearance of the CSF collection that lies between the frontal horns and bodies of the lateral ventricle.](images/app.statdx.com_image_thumbnail_80289a63-e206-480d-8e27-773285024d3e_annotated_true_size_900_quality_90_50066962_20251018T164843Z.jpg)
+*Axial T1 MR shows a small cavum septi pellucidi with cavum vergae <img src='/img/arrows/CS.png'/>. Note the finger-like appearance of the CSF collection that lies between the frontal horns and bodies of the lateral ventricle.*
+
+![Axial T2 MR shows a variant of a cavum septi pellucidi with cavum vergae. Note the large CSF collection between leaves of septum pellucidum <img src='/img/arrows/BO.png'/> continuing directly posteriorly with the CSF collection, splaying the fornices laterally <img src='/img/arrows/BS.png'/>.](a9f16e39-5902-4fff-ba93-4c486599b232)
+*Axial T2 MR shows a variant of a cavum septi pellucidi with cavum vergae. Note the large CSF collection between leaves of septum pellucidum <img src='/img/arrows/BO.png'/> continuing directly posteriorly with the CSF collection, splaying the fornices laterally <img src='/img/arrows/BS.png'/>.*
+
+![Axial T2 MR shows cavum septi pellucidi as a CSF collection between the leaves of the septum pellucidum <img src='/img/arrows/CO.png'/>. Although seen incidentally, some studies have reported that CSP is frequent among athletes with a history of repeated TBI, such as boxers and American professional football players.](1fd75692-6b22-492c-916e-20211f0706ea)
+*Axial T2 MR shows cavum septi pellucidi as a CSF collection between the leaves of the septum pellucidum <img src='/img/arrows/CO.png'/>. Although seen incidentally, some studies have reported that CSP is frequent among athletes with a history of repeated TBI, such as boxers and American professional football players.*
+
+![Coronal T1 MR shows a classic large CSP between the frontal horns <img src='/img/arrows/CS.png'/>, bowing the leaves of the septum pellucidum laterally <img src='/img/arrows/CC.png'/>.](6e082f2e-afc6-402e-b55e-9e70eb8461d2)
+*Coronal T1 MR shows a classic large CSP between the frontal horns <img src='/img/arrows/CS.png'/>, bowing the leaves of the septum pellucidum laterally <img src='/img/arrows/CC.png'/>.*
+

docs_md/articles/cavum-velum-interpositum-cvi_849ee468-35c4-46e3-9297-96196109cdb8.md

@@ -0,0 +1,315 @@
+---
+title: "Cavum Velum Interpositum (CVI)"
+docid: "849ee468-35c4-46e3-9297-96196109cdb8"
+authors:
+  - key: "a25c450b-3d34-4f64-bba3-cc0834813df6"
+    value: "Miral D. Jhaveri, MD, MBA"
+  - key: "5cff4116-3654-4b3a-bb75-5ebe0b8c9850"
+    value: "Anne G. Osborn, MD, FACR"
+breadcrumbs:
+  -
+    name: "Brain"
+    slug: "brain"
+    treeNodeId: "6d8829f1-14d7-45af-8675-255189aa526a"
+  -
+    name: "Diagnosis"
+    slug: "diagnosis"
+    treeNodeId: "51c00394-446e-4a38-94af-d3b1d14d34e8"
+  -
+    name: "Anatomy-Based Diagnoses"
+    slug: "anatomy-based-diagnoses"
+    treeNodeId: "529d3e33-f508-498c-bc70-cf962e81e629"
+  -
+    name: "Ventricles and Cisterns"
+    slug: "ventricles-and-cisterns"
+    treeNodeId: "33b267f0-908c-4c77-81f8-f6135d1bc592"
+  -
+    name: "Normal Variants"
+    slug: "normal-variants"
+    treeNodeId: "bf92256f-cdff-4bcd-8420-d876b9e4031a"
+  -
+    name: "Cavum Velum Interpositum (CVI)"
+    slug: "cavum-velum-interpositum-cvi"
+    treeNodeId: null
+category: "Brain"
+documentVersionId: "75312185-3ddd-4300-a4fb-d824b606effc"
+imageCount: 12
+lastUpdated: "05/08/20"
+pageDescription: "Cavum Velum Interpositum (CVI)"
+pageKeywords: "Brain, Diagnosis, Anatomy-Based Diagnoses, Ventricles and Cisterns, Normal Variants, Cavum Velum Interpositum (CVI)"
+pageTitle: "Cavum Velum Interpositum (CVI) | STATdx"
+enhancedTitle: "Cavum Velum Interpositum (CVI)"
+type: "DX"
+references: true
+breadcrumbs:
+  - "Brain"
+  - "Diagnosis"
+  - "Anatomy-Based Diagnoses"
+  - "Ventricles and Cisterns"
+  - "Normal Variants"
+  - "Cavum Velum Interpositum (CVI)"
+---
+# KEY FACTS
+
+- ## Terminology
+  
+  
+    - Cavum velum interpositum (CVI), cyst of velum interpositum (VI)
+- ## Imaging
+  
+  
+    - Triangular CSF space
+          - Between lateral ventricles, over thalami
+          - Apex points toward foramen of Monro
+          - Elevates, splays fornices
+          - Flattens, displaces internal cerebral veins inferiorly
+    - Size varies from slit-like linear to triangular to round/ovoid CSF collection
+    - Isodense/isointense with CSF
+          - Suppresses completely on FLAIR
+          - Does not restrict on DWI
+          - Does not enhance
+    - US shows hypoechoic midline interhemispheric cyst
+- ## Top Differential Diagnoses
+  
+  
+    - Normal cistern of velum interpositum
+    - Cavum septi pellucidi, cavum vergae
+    - Arachnoid cyst
+    - Epidermoid cyst
+- ## Clinical Issues
+  
+  
+    - Can be found at any age
+          - Common in infants, rare in adults
+    - Symptoms
+          - Usually asymptomatic, found incidentally
+          - Headache (relationship to cyst unclear)
+          - Large CVI can obstruct normal CSF flow; treated by endoscopic fenestration
+- ## Diagnostic Checklist
+  
+  
+    - CSF-like "cyst" could be epidermoid
+    - Include FLAIR and DWI to distinguish between CVI, epidermoid cyst
+
+# TERMINOLOGY
+
+- ## Abbreviations
+  
+  
+    - Cavum velum interpositum (CVI), cyst of velum interpositum (VI)
+- ## Definitions
+  
+  
+    - Cystic dilation of VI
+
+# IMAGING
+
+- ## General Features
+  
+  
+    - ### Best diagnostic clue
+      
+      
+          - Triangular-shaped CSF space
+                  - Between lateral ventricles, over thalami
+                  - Apex points toward but does not extend anteriorly beyond foramen of Monro
+                  - Base contiguous with quadrigeminal cistern
+    - ### Location
+      
+      
+          - Midline between lateral ventricles, below fornices
+          - Continuous with choroid plexus subependymally
+    - ### Size
+      
+      
+          - Varies (few mm to several cm)
+- ## CT Findings
+  
+  
+    - ### NECT
+      
+      
+          - Triangle of CSF between lateral ventricles
+    - ### CECT
+      
+      
+          - Does not enhance
+- ## MR Findings
+  
+  
+    - ### T1WI
+      
+      
+          - Sagittal: Varies from slit-like linear to round/ovoid
+                  - Elevates fornices
+                  - Flattens, displaces internal cerebral veins inferiorly
+          - Axial: Triangle of CSF between lateral ventricles
+    - ### T2WI
+      
+      
+          - Isointense with CSF
+    - ### FLAIR
+      
+      
+          - Suppresses completely
+    - ### DWI
+      
+      
+          - Does not restrict
+- ## Ultrasonographic Findings
+  
+  
+    - ### Color Doppler
+      
+      
+          - Hypoechoic midline interhemispheric cyst
+- ## Imaging Recommendations
+  
+  
+    - ### Best imaging tool
+      
+      
+          - MR ± contrast
+    - ### Protocol advice
+      
+      
+          - FLAIR/DWI (distinguish between CVI and epidermoid)
+
+# DIFFERENTIAL DIAGNOSIS
+
+- [Normal Cistern of Velum Interpositum](/document/pineal-cyst/eda99e5c-c992-4798-aa35-21437eb505ea)
+    - Usually small (slit-like or oval)
+    - Does not elevate fornices or depress internal cerebral veins
+- ## Cavum Septi Pellucidi, Vergae
+  
+  
+    - CSP + CV elongated, finger-like CSF space
+- [Arachnoid Cyst](/document/arachnoid-cyst/7d63f0d3-6999-4d8c-a41d-953f738c43a6)
+    - Lined with arachnoid (may be indistinguishable)
+- [Epidermoid Cyst](/document/epidermoid-cyst/704c5ddf-e1f7-4a5d-a1b8-5b0e603170d9)
+    - Lobulated, insinuating mass
+    - Does not suppress with FLAIR; DWI shows restriction
+
+# PATHOLOGY
+
+- ## General Features
+  
+  
+    - ### Etiology
+      
+      
+          - Pia infolds along transverse fissure, forms CSF cistern (VI)
+          - Cystic dilatation of VI may occur (precise etiology unknown)
+    - ### Associated abnormalities
+      
+      
+          - Usually none (large CVIs may cause hydrocephalus)
+- ## Gross Pathologic & Surgical Features
+  
+  
+    - Normal cistern of VI is small to inapparent at autopsy
+    - Pial-lined CSF-filled space
+- ## Microscopic Features
+  
+  
+    - Occasionally cysts of midline CSF spaces contain glial cells, scattered neurons
+
+# CLINICAL ISSUES
+
+- ## Presentation
+  
+  
+    - ### Most common signs/symptoms
+      
+      
+          - Usually asymptomatic, found incidentally
+          - Headache (relationship to cyst unclear)
+- ## Demographics
+  
+  
+    - ### Age
+      
+      
+          - Can be found at any age
+                  - Common in infants, rare in adults
+    - ### Gender
+      
+      
+          - M = F
+- ## Treatment
+  
+  
+    - Usually none
+
+# DIAGNOSTIC CHECKLIST
+
+- ## Consider
+  
+  
+    - CSF-like "cyst" could be epidermoid
+    - Use DWI, FLAIR to differentiate from other cysts
+
+ 806ab3b4-9c9a-4887-a52d-d5809cd5a417
+
+## References
+
+# Selected References
+
+1. [Krejčí T et al: Symptomatic cysts of the cavum septi pellucidi, cavum vergae and cavum veli interpositi: A retrospective duocentric study of 10 patients. Clin Neurol Neurosurg. 185:105494, 2019](http://www.ncbi.nlm.nih.gov/pubmed/?term=31472394%5Bpmid%5D)
+1. [Akinola RA et al: Caval variations in neurologically diseased patients. Acta Radiol Short Rep. 3(5):2047981614530288, 2014](http://www.ncbi.nlm.nih.gov/pubmed/?term=25298867%5Bpmid%5D)
+1. [Tong CK et al: Endoscopic fenestration of cavum velum interpositum cysts: a case study of two symptomatic patients. Childs Nerv Syst. 28(8):1261-4, 2012](http://www.ncbi.nlm.nih.gov/pubmed/?term=22543434%5Bpmid%5D)
+1. [Tubbs RS et al: Cavum velum interpositum, cavum septum pellucidum, and cavum vergae: a review. Childs Nerv Syst. 27(11):1927-30, 2011](http://www.ncbi.nlm.nih.gov/pubmed/?term=21687999%5Bpmid%5D)
+1. [Tubbs RS et al: The velum interpositum revisited and redefined. Surg Radiol Anat. 30(2):131-5, 2008](http://www.ncbi.nlm.nih.gov/pubmed/?term=18094919%5Bpmid%5D)
+1. [Osborn AG et al: Intracranial cysts: radiologic-pathologic correlation and imaging approach. Radiology. 239(3):650-64, 2006](http://www.ncbi.nlm.nih.gov/pubmed/?term=16714456%5Bpmid%5D)
+1. [Eisenberg VH et al: Prenatal diagnosis of cavum velum interpositum cysts: significance and outcome. Prenat Diagn. 23(10):779-83, 2003](http://www.ncbi.nlm.nih.gov/pubmed/?term=14558018%5Bpmid%5D)
+1. [Vergani P et al: Ultrasonographic differential diagnosis of fetal intracranial interhemispheric cysts. Am J Obstet Gynecol. 180(2 Pt 1):423-8, 1999](http://www.ncbi.nlm.nih.gov/pubmed/?term=9988813%5Bpmid%5D)
+1. [Chen CY et al: Sonographic characteristics of the cavum velum interpositum. AJNR Am J Neuroradiol. 19(9):1631-5, 1998](http://www.ncbi.nlm.nih.gov/pubmed/?term=9802483%5Bpmid%5D)
+
+
+## Images
+
+
+### Selected Images
+
+![Sagittal graphic with axial insert shows a cavum velum interpositum (CVI). Note the elevation and splaying of the fornices <img src='/img/arrows/WO.png'/>. Also noted is the inferior displacement of the internal cerebral veins and 3rd ventricle <img src='/img/arrows/WS.png'/>.](images/app.statdx.com_image_thumbnail_2df127e7-04ef-413c-b33e-46703bf26fc3_annotated_true_size_900_quality_90_43c5eb31_20251018T164844Z.jpg)
+*Sagittal graphic with axial insert shows a cavum velum interpositum (CVI). Note the elevation and splaying of the fornices <img src='/img/arrows/WO.png'/>. Also noted is the inferior displacement of the internal cerebral veins and 3rd ventricle <img src='/img/arrows/WS.png'/>.*
+
+![Sagittal graphic with axial insert shows a cavum velum interpositum (CVI). Note the elevation and splaying of the fornices <img src='/img/arrows/WO.png'/>. Also noted is the inferior displacement of the internal cerebral veins and 3rd ventricle <img src='/img/arrows/WS.png'/>.](images/app.statdx.com_image_thumbnail_2df127e7-04ef-413c-b33e-46703bf26fc3_size_174_quality_85_6f6a77c4_20251018T164756Z.jpg)
+*Sagittal graphic with axial insert shows a cavum velum interpositum (CVI). Note the elevation and splaying of the fornices <img src='/img/arrows/WO.png'/>. Also noted is the inferior displacement of the internal cerebral veins and 3rd ventricle <img src='/img/arrows/WS.png'/>.*
+
+![Sagittal T1 MR shows a classic CVI <img src='/img/arrows/CC.png'/> as a CSF-like enlargement that elevates the fornix <img src='/img/arrows/CS.png'/> and flattens and displaces the internal cerebral vein <img src='/img/arrows/CO.png'/> inferiorly. These are usually asymptomatic; however, large ones can cause CSF obstruction and can be treated by fenestration.](images/app.statdx.com_image_thumbnail_bc8c67a9-f3e5-4673-a4f6-3febba3eccd9_annotated_true_size_900_quality_90_39cc402c_20251018T164845Z.jpg)
+*Sagittal T1 MR shows a classic CVI <img src='/img/arrows/CC.png'/> as a CSF-like enlargement that elevates the fornix <img src='/img/arrows/CS.png'/> and flattens and displaces the internal cerebral vein <img src='/img/arrows/CO.png'/> inferiorly. These are usually asymptomatic; however, large ones can cause CSF obstruction and can be treated by fenestration.*
+
+![Axial T2 MR in a 37-year-old man with headaches shows a triangular-shaped CSF collection <img src='/img/arrows/CS.png'/> between the lateral ventricles, spreading the fornices laterally <img src='/img/arrows/CC.png'/>.](images/app.statdx.com_image_thumbnail_e9fcc6c7-e349-4a26-8cd1-1585a0da8e2e_annotated_true_size_900_quality_90_0de56902_20251018T164845Z.jpg)
+*Axial T2 MR in a 37-year-old man with headaches shows a triangular-shaped CSF collection <img src='/img/arrows/CS.png'/> between the lateral ventricles, spreading the fornices laterally <img src='/img/arrows/CC.png'/>.*
+
+![Axial FLAIR MR in the same patient shows complete suppression of the CSF signal within the cyst <img src='/img/arrows/CC.png'/> similar to the lateral ventricles. Findings are consistent with a classic cavum velum interpositum. FLAIR and DWI distinguish between cavum velum interpositum and an epidermoid cyst.](images/app.statdx.com_image_thumbnail_a2c60186-2347-4c48-b827-1bae6f61ff3d_annotated_true_size_900_quality_90_f9c0e3e7_20251018T164845Z.jpg)
+*Axial FLAIR MR in the same patient shows complete suppression of the CSF signal within the cyst <img src='/img/arrows/CC.png'/> similar to the lateral ventricles. Findings are consistent with a classic cavum velum interpositum. FLAIR and DWI distinguish between cavum velum interpositum and an epidermoid cyst.*
+
+
+### Additional Images
+
+![Axial T2 MR shows a cavum septi pellucidi (CSP) <img src='/img/arrows/BO.png'/> along with a very small cavum velum interpositum <img src='/img/arrows/BS.png'/>. Note that these 2 unrelated lesions do not communicate with each other. It is common to see a CSP with a cavum vergae; it is rare to see a CSP and a CVI in the same patient.](images/app.statdx.com_image_thumbnail_8f807265-867d-45c4-a0e0-d4b5ed77ec48_annotated_true_size_900_quality_90_14754121_20251018T164844Z.jpg)
+*Axial T2 MR shows a cavum septi pellucidi (CSP) <img src='/img/arrows/BO.png'/> along with a very small cavum velum interpositum <img src='/img/arrows/BS.png'/>. Note that these 2 unrelated lesions do not communicate with each other. It is common to see a CSP with a cavum vergae; it is rare to see a CSP and a CVI in the same patient.*
+
+![Coronal T1 C+ MR shows classic cavum velum interpositum <img src='/img/arrows/CO.png'/> that spreads the fornices <img src='/img/arrows/CS.png'/> apart.](images/app.statdx.com_image_thumbnail_52a1d3d4-3d12-4d0c-99df-2eea486bbc3b_annotated_true_size_900_quality_90_8a9e912a_20251018T164845Z.jpg)
+*Coronal T1 C+ MR shows classic cavum velum interpositum <img src='/img/arrows/CO.png'/> that spreads the fornices <img src='/img/arrows/CS.png'/> apart.*
+
+![Axial T2 MR shows a small, triangular-shaped CSF space. Note the cavum velum interpositum <img src='/img/arrows/CO.png'/> interposed between the fornices <img src='/img/arrows/BS.png'/> and lateral ventricles. The CVI ends at the foramen of Monro.](images/app.statdx.com_image_thumbnail_1d26fd47-cf3a-49e9-b019-149ab6aa9d95_annotated_true_size_900_quality_90_3b864288_20251018T164844Z.jpg)
+*Axial T2 MR shows a small, triangular-shaped CSF space. Note the cavum velum interpositum <img src='/img/arrows/CO.png'/> interposed between the fornices <img src='/img/arrows/BS.png'/> and lateral ventricles. The CVI ends at the foramen of Monro.*
+
+![Axial T1 MR shows a very large cavum velum interpositum. Note the splaying of fornices <img src='/img/arrows/WS.png'/> and anterior displacement of the septum pellucidum <img src='/img/arrows/WO.png'/>. Mild enlargement of the lateral ventricles is seen.](images/app.statdx.com_image_thumbnail_21237160-fb5d-46fc-8708-36027df8182c_annotated_true_size_900_quality_90_227e0506_20251018T164845Z.jpg)
+*Axial T1 MR shows a very large cavum velum interpositum. Note the splaying of fornices <img src='/img/arrows/WS.png'/> and anterior displacement of the septum pellucidum <img src='/img/arrows/WO.png'/>. Mild enlargement of the lateral ventricles is seen.*
+
+![Sagittal T1 MR in the same patient shows anterior/superior displacement of the fornix <img src='/img/arrows/CC.png'/> and inferior displacement of the 3rd ventricle <img src='/img/arrows/CO.png'/>. The corpus callosum is elevated and thinned.](570ac479-0220-4e7c-95cf-b05fa1d08c4f)
+*Sagittal T1 MR in the same patient shows anterior/superior displacement of the fornix <img src='/img/arrows/CC.png'/> and inferior displacement of the 3rd ventricle <img src='/img/arrows/CO.png'/>. The corpus callosum is elevated and thinned.*
+
+![Sagittal T1 MR in a 40-year-old woman with headaches shows CSF-like enlargement of the velum interpositum <img src='/img/arrows/BC.png'/> that elevates the fornix <img src='/img/arrows/BS.png'/> and flattens and displaces the internal cerebral vein inferiorly <img src='/img/arrows/BO.png'/>. This large CVI is probably unrelated to the patient's symptoms.](15050721-daf0-49a6-a3f3-45a4a2b17b85)
+*Sagittal T1 MR in a 40-year-old woman with headaches shows CSF-like enlargement of the velum interpositum <img src='/img/arrows/BC.png'/> that elevates the fornix <img src='/img/arrows/BS.png'/> and flattens and displaces the internal cerebral vein inferiorly <img src='/img/arrows/BO.png'/>. This large CVI is probably unrelated to the patient's symptoms.*
+
+![Axial T2 MR in a 46-year-old woman with headaches shows a classic CVI with a triangular-shaped CSF collection <img src='/img/arrows/WO.png'/>, spreading the fornices laterally <img src='/img/arrows/WS.png'/>. The posterior location between the lateral ventricles is typical.](368270d4-dee5-4f8e-8b6e-47b96373ed43)
+*Axial T2 MR in a 46-year-old woman with headaches shows a classic CVI with a triangular-shaped CSF collection <img src='/img/arrows/WO.png'/>, spreading the fornices laterally <img src='/img/arrows/WS.png'/>. The posterior location between the lateral ventricles is typical.*
+
+![Sagittal T1 MR shows a variant CVI <img src='/img/arrows/CS.png'/> that elevates the fornix <img src='/img/arrows/BS.png'/>, flattens the internal cerebral vein <img src='/img/arrows/CC.png'/>, and extends into the quadrigeminal and suprasellar cisterns <img src='/img/arrows/CO.png'/>. This case probably represents an arachnoid cyst of the cavum velum interpositum.](b6d129c7-1434-422d-91d7-83b43bc72494)
+*Sagittal T1 MR shows a variant CVI <img src='/img/arrows/CS.png'/> that elevates the fornix <img src='/img/arrows/BS.png'/>, flattens the internal cerebral vein <img src='/img/arrows/CC.png'/>, and extends into the quadrigeminal and suprasellar cisterns <img src='/img/arrows/CO.png'/>. This case probably represents an arachnoid cyst of the cavum velum interpositum.*
+

docs_md/articles/corpus-callosum-impingement-syndrome_e84adf32-bae3-47d5-b368-489f413f6aea.md

@@ -0,0 +1,305 @@
+---
+title: "Corpus Callosum Impingement Syndrome"
+docid: "e84adf32-bae3-47d5-b368-489f413f6aea"
+authors:
+  - key: "a25c450b-3d34-4f64-bba3-cc0834813df6"
+    value: "Miral D. Jhaveri, MD, MBA"
+breadcrumbs:
+  -
+    name: "Brain"
+    slug: "brain"
+    treeNodeId: "6d8829f1-14d7-45af-8675-255189aa526a"
+  -
+    name: "Diagnosis"
+    slug: "diagnosis"
+    treeNodeId: "51c00394-446e-4a38-94af-d3b1d14d34e8"
+  -
+    name: "Anatomy-Based Diagnoses"
+    slug: "anatomy-based-diagnoses"
+    treeNodeId: "529d3e33-f508-498c-bc70-cf962e81e629"
+  -
+    name: "Ventricles and Cisterns"
+    slug: "ventricles-and-cisterns"
+    treeNodeId: "33b267f0-908c-4c77-81f8-f6135d1bc592"
+  -
+    name: "Hydrocephalus"
+    slug: "hydrocephalus"
+    treeNodeId: "9ce86e3b-fab6-4657-9e51-5f47bb1a51b5"
+  -
+    name: "Corpus Callosum Impingement Syndrome"
+    slug: "corpus-callosum-impingement-syndro-"
+    treeNodeId: null
+category: "Brain"
+documentVersionId: "2188842b-0f05-4580-9c01-5ee89586a08f"
+imageCount: 4
+lastUpdated: "06/09/20"
+pageDescription: "Corpus Callosum Impingement Syndrome"
+pageKeywords: "Brain, Diagnosis, Anatomy-Based Diagnoses, Ventricles and Cisterns, Hydrocephalus, Corpus Callosum Impingement Syndrome"
+pageTitle: "Corpus Callosum Impingement Syndrome | STATdx"
+enhancedTitle: "Corpus Callosum Impingement Syndrome"
+type: "DX"
+references: true
+breadcrumbs:
+  - "Brain"
+  - "Diagnosis"
+  - "Anatomy-Based Diagnoses"
+  - "Ventricles and Cisterns"
+  - "Hydrocephalus"
+  - "Corpus Callosum Impingement Syndrome"
+---
+# KEY FACTS
+
+- ## Terminology
+  
+  
+    - Corpus callosum impingement syndrome (CCIS)
+    - Corpus callosum (CC)
+    - Callosal injury from longstanding obstructive hydrocephalus
+- ## Imaging
+  
+  
+    - Acute
+          - Following ventricular decompression in longstanding obstructive hydrocephalus
+          - Swollen and hyperintense body of CC
+          - Diffuse or focal hyperintense areas in CC
+    - Chronic
+          - Encephalomalacic foci, shrunken and atrophic-appearing CC
+    - No hemorrhage, restricted diffusion, or enhancement
+- ## Top Differential Diagnoses
+  
+  
+    - **Acute phase: CC swollen with T2/FLAIR hyperintensity**
+          - Tumors involving CC, tumefactive demyelination, transient cytotoxic splenial lesion, ischemia/infarct, diffuse axonal injury
+    - **Chronic phase: CC atrophy with cystic changes**
+          - Multiple sclerosis, postsurgical, enlarged perivascular spaces, Marchiafava-Bignami disease, Susac syndrome
+- ## Pathology
+  
+  
+    - Exact mechanism for callosal lesions unknown
+- ## Clinical Issues
+  
+  
+    - CC injury does not appear to produce any clinically recognizable symptomatology
+    - CCIS is uncommon sequel of severe chronic hydrocephalus
+    - Longstanding cases: Atrophic CC and signal abnormality, may persist after ventricular decompression
+- ## Diagnostic Checklist
+  
+  
+    - Consider CCIS in patient treated with ventricular decompression for longstanding obstructive hydrocephalus
+    - CC signal change, although dramatic, should not be mistaken for other pathologies
+
+# TERMINOLOGY
+
+- ## Abbreviations
+  
+  
+    - Corpus callosum impingement syndrome (CCIS)
+    - Corpus callosum (CC)
+- ## Definitions
+  
+  
+    - Callosal injury from longstanding obstructive hydrocephalus
+
+# IMAGING
+
+- ## General Features
+  
+  
+    - ### Best diagnostic clue
+      
+      
+          - Diffuse &/or focal T2/FLAIR hyperintensity in CC
+    - ### Location
+      
+      
+          - Isthmus, body of CC, splenium generally spared
+    - ### Size
+      
+      
+          - Variable
+    - ### Morphology
+      
+      
+          - Ill-defined or focal lesions
+- ## CT Findings
+  
+  
+    - Thinning and upward displacement of CC
+    - Postventricular decompression or shunting
+          - Acute: Swollen, hypodense body of CC
+          - Chronic: Atrophy, cystic changes in body of CC
+- ## MR Findings
+  
+  
+    - ### T1WI
+      
+      
+          - Severe hydrocephalus with upward bowing and thinning of CC
+          - Following ventricular decompression, swollen hypointense body of CC
+    - ### T2WI
+      
+      
+          - Acute
+                  - Following ventricular decompression
+                  - Swollen, hyperintense body of CC
+                  - Diffuse or focal hyperintense areas
+                  - May see periventricular white matter (WM) hyperintensities
+          - Chronic
+                  - Encephalomalacic foci, shrunken and atrophic-appearing CC
+    - ### FLAIR
+      
+      
+          - More sensitive to evaluate CC and periventricular WM
+    - ### T2* GRE
+      
+      
+          - No hemorrhage
+    - ### DWI
+      
+      
+          - No restricted diffusion
+    - ### T1WI C+
+      
+      
+          - No enhancement
+    - DTI: Fiber disruption in body of CC
+- ## Imaging Recommendations
+  
+  
+    - ### Best imaging tool
+      
+      
+          - MR
+    - ### Protocol advice
+      
+      
+          - Add sagittal T2/FLAIR
+
+# DIFFERENTIAL DIAGNOSIS
+
+- ## Acute Phase: Corpus Callosum Swollen With T2/FLAIR Hyperintensity
+  
+  
+    - **Tumors involving CC**
+          - Lymphoma: Uniform enhancement, restricted diffusion
+          - Glioblastoma: Central necrosis, irregular enhancement
+    - [Tumefactive demyelination](/document/demyelinating-diseases/e3ba880e-d924-4594-a6f4-c21c5f1f0ae7)
+          - Often incomplete, horseshoe-shaped enhancement
+    - **Transient cytotoxic splenial lesion**
+          - Round or boomerang-shaped diffusion restriction in CC splenium, diverse etiologies
+    - [Ischemia/infarct](/document/acute-cerebral-ischemiainfarction/a405285f-aaea-43ca-8dc4-6f8120eaabc1)
+          - Diffusion restriction in CC likely due to "acute wallerian degeneration"
+    - [Diffuse axonal injury (DAI)](/document/diffuse-axonal-injury/c67bbb31-aea3-420f-b65f-de49bb26fcfc)
+          - Signal loss on SWI, ↑ T2, diffusion restriction
+    - **Interstitial edema (obstructive hydrocephalus)**
+          - ↑ T2/FLAIR signal along CC ventricular surface
+          - Look for additional abnormal signal of frontal and occipital periventricular WM
+- ## Chronic Phase: Corpus Callosum Atrophy With Cystic Changes
+  
+  
+    - [Multiple sclerosis](/document/multiple-sclerosis/7892b2a2-f52a-4d7f-9858-a326f2b7ab04)
+          - "Burned-out" chronic lesions
+    - **Postsurgical**
+          - Small CC "holes" common after shunt
+          - Corpus callosotomy
+    - [Enlarged perivascular spaces](/document/enlarged-perivascular-spaces/58fff1ec-50b7-4caf-ab31-3341ab7044c9)
+          - Follow CSF on all sequences
+          - When CC involved, adjacent brain often involved
+    - [Marchiafava-Bignami disease](/document/alcoholic-encephalopathy/88021852-b73d-4cdf-a719-dd4ae3231e45)
+          - Rare complication of chronic alcoholism
+          - T2-hyperintense CC (middle layers)
+    - **Susac syndrome**
+          - Encephalopathy, visual changes, hearing loss
+          - Multifocal supratentorial WM lesions + CC
+
+# PATHOLOGY
+
+- ## General Features
+  
+  
+    - ### Etiology
+      
+      
+          - Exact mechanism for callosal lesions unknown
+          - Mechanical compression
+                  - Severe obstructive hydrocephalus
+                  - CC compressed against free inferior margin of falx
+                  - Pressure necrosis
+          - Ventricular decompression associated edema
+          - Compromised venous drainage
+          - Traction-induced arterial compromise, demyelination
+- ## Gross Pathologic & Surgical Features
+  
+  
+    - Chronic impingement of CC associated with callosal thinning, cystic changes
+- ## Microscopic Features
+  
+  
+    - Loss of callosal axons
+
+# CLINICAL ISSUES
+
+- ## Presentation
+  
+  
+    - ### Most common signs/symptoms
+      
+      
+          - Signs/symptoms related to obstructive hydrocephalus
+          - CCIS does not appear to produce any clinically recognizable symptoms
+- ## Demographics
+  
+  
+    - CCIS uncommon sequela of severe chronic hydrocephalus
+    - MR CC signal change in 8.3% of patients following shunt insertion for obstructive hydrocephalus
+- ## Natural History & Prognosis
+  
+  
+    - Ventricular decompression may reverse CC signal change
+    - Longstanding cases: Atrophic CC and signal abnormality, may persist after ventricular decompression
+    - No long-term neurologic sequel from callosal damage
+- ## Treatment
+  
+  
+    - None for CC signal abnormality
+
+# DIAGNOSTIC CHECKLIST
+
+- ## Consider
+  
+  
+    - CCIS in patient treated with ventricular decompression for longstanding obstructive hydrocephalus
+- ## Image Interpretation Pearls
+  
+  
+    - CC signal change, although dramatic, should not be mistaken for other pathologies
+
+ ef393b1c-c6e2-4c4a-b4db-ada4a6ccd7cb
+
+## References
+
+# Selected References
+
+1. [Su S et al: Post-shunting corpus callosal signal change and review of the literature. J Clin Neurosci. 72:466-8, 2020](http://www.ncbi.nlm.nih.gov/pubmed/?term=31874812%5Bpmid%5D)
+1. [Oon SF et al: Corpus callosum impingement syndrome: a callosal or colossal problem? Can J Neurol Sci. 44(6):728-9, 2017](http://www.ncbi.nlm.nih.gov/pubmed/?term=29391083%5Bpmid%5D)
+1. [Ferrara JM: Signal hyperintensity of the callosum after ventriculoperitoneal shunting. Neurology. 84(15):1609-10, 2015](http://www.ncbi.nlm.nih.gov/pubmed/?term=25870451%5Bpmid%5D)
+1. [Lane JI et al: Corpus callosal signal changes in patients with obstructive hydrocephalus after ventriculoperitoneal shunting. AJNR Am J Neuroradiol. 22(1):158-62, 2001](http://www.ncbi.nlm.nih.gov/pubmed/?term=11158902%5Bpmid%5D)
+
+
+## Images
+
+
+### Selected Images
+
+![Sagittal T1 MR in a patient with longstanding severe obstructive hydrocephalus demonstrates markedly dilated lateral ventricle with upward displacement and thinning of the corpus callosum (CC)  <img src='/img/arrows/CC.png'/>. Note the shunt catheter <img src='/img/arrows/CS.png'/>, which was placed immediately before the scan.](images/app.statdx.com_image_thumbnail_190b394f-861b-42e4-909b-125648b68eed_annotated_true_size_900_quality_90_06683e2f_20251018T160022Z.jpg)
+*Sagittal T1 MR in a patient with longstanding severe obstructive hydrocephalus demonstrates markedly dilated lateral ventricle with upward displacement and thinning of the corpus callosum (CC)  <img src='/img/arrows/CC.png'/>. Note the shunt catheter <img src='/img/arrows/CS.png'/>, which was placed immediately before the scan.*
+
+![Sagittal T1 MR in the same patient 7 days after placement of the shunt catheter <img src='/img/arrows/CS.png'/> shows patchy areas of low signal in the CC <img src='/img/arrows/CC.png'/>. Lateral ventricles are now decompressed, and there is no mass effect on the CC.](images/app.statdx.com_image_thumbnail_a662615a-810a-4a2d-830f-573e159d170a_annotated_true_size_900_quality_90_1d3bc703_20251018T160022Z.jpg)
+*Sagittal T1 MR in the same patient 7 days after placement of the shunt catheter <img src='/img/arrows/CS.png'/> shows patchy areas of low signal in the CC <img src='/img/arrows/CC.png'/>. Lateral ventricles are now decompressed, and there is no mass effect on the CC.*
+
+![Axial FLAIR MR in the same patient 7 days following placement of the shunt catheter demonstrates ill-defined hyperintensities in the body of the CC <img src='/img/arrows/CC.png'/> as well as in the periventricular white matter <img src='/img/arrows/CS.png'/>. Note decompressed lateral and 3rd ventricles.](images/app.statdx.com_image_thumbnail_8a95800b-56d9-4311-bf1b-3fd3a6302496_annotated_true_size_900_quality_90_e12da5be_20251018T160022Z.jpg)
+*Axial FLAIR MR in the same patient 7 days following placement of the shunt catheter demonstrates ill-defined hyperintensities in the body of the CC <img src='/img/arrows/CC.png'/> as well as in the periventricular white matter <img src='/img/arrows/CS.png'/>. Note decompressed lateral and 3rd ventricles.*
+
+![Axial FLAIR MR in the same patient 1 month after placement of the shunt shows mild decrease in the hyperintensities in the CC <img src='/img/arrows/CC.png'/> as well as the periventricular white matter <img src='/img/arrows/CS.png'/> with further decompression of the lateral and 3rd ventricles.](images/app.statdx.com_image_thumbnail_f93749c2-5c2a-43fb-9cc6-55a6f3b93079_annotated_true_size_900_quality_90_f97b7f6a_20251018T160022Z.jpg)
+*Axial FLAIR MR in the same patient 1 month after placement of the shunt shows mild decrease in the hyperintensities in the CC <img src='/img/arrows/CC.png'/> as well as the periventricular white matter <img src='/img/arrows/CS.png'/> with further decompression of the lateral and 3rd ventricles.*
+

docs_md/articles/csf-shunts-and-complications_1027d634-92ff-47c1-8266-a7fc3acd1529.md

@@ -0,0 +1,531 @@
+---
+title: "CSF Shunts and Complications"
+docid: "1027d634-92ff-47c1-8266-a7fc3acd1529"
+authors:
+  - key: "a25c450b-3d34-4f64-bba3-cc0834813df6"
+    value: "Miral D. Jhaveri, MD, MBA"
+  - key: "99e1aff7-f42c-43a0-95ae-d89c8551aa01"
+    value: "Kevin R. Moore, MD"
+breadcrumbs:
+  -
+    name: "Brain"
+    slug: "brain"
+    treeNodeId: "6d8829f1-14d7-45af-8675-255189aa526a"
+  -
+    name: "Diagnosis"
+    slug: "diagnosis"
+    treeNodeId: "51c00394-446e-4a38-94af-d3b1d14d34e8"
+  -
+    name: "Anatomy-Based Diagnoses"
+    slug: "anatomy-based-diagnoses"
+    treeNodeId: "529d3e33-f508-498c-bc70-cf962e81e629"
+  -
+    name: "Ventricles and Cisterns"
+    slug: "ventricles-and-cisterns"
+    treeNodeId: "33b267f0-908c-4c77-81f8-f6135d1bc592"
+  -
+    name: "Hydrocephalus"
+    slug: "hydrocephalus"
+    treeNodeId: "9ce86e3b-fab6-4657-9e51-5f47bb1a51b5"
+  -
+    name: "CSF Shunts and Complications"
+    slug: "csf-shunts-and-complications"
+    treeNodeId: null
+category: "Brain"
+documentVersionId: "201dad63-bfb4-4f05-ade4-1140c667d000"
+imageCount: 23
+lastUpdated: "09/24/20"
+pageDescription: "CSF Shunts and Complications"
+pageKeywords: "Brain, Diagnosis, Anatomy-Based Diagnoses, Ventricles and Cisterns, Hydrocephalus, CSF Shunts and Complications"
+pageTitle: "CSF Shunts and Complications | STATdx"
+enhancedTitle: "CSF Shunts and Complications"
+type: "DX"
+references: true
+breadcrumbs:
+  - "Brain"
+  - "Diagnosis"
+  - "Anatomy-Based Diagnoses"
+  - "Ventricles and Cisterns"
+  - "Hydrocephalus"
+  - "CSF Shunts and Complications"
+---
+# KEY FACTS
+
+- ## Terminology
+  
+  
+    - Hydrocephalus (HCP)
+          - Enlargement of cerebral ventricles secondary to abnormal CSF formation, flow, or absorption resulting in ↑ CSF volume
+- ## Imaging
+  
+  
+    - Shunt failure → dilated ventricles + edema around ventricles, along catheter and reservoir
+    - Use CT or MR to evaluate ventricle size, plain radiograph shunt series to identify mechanical shunt failure
+    - Baseline CT/MR following shunt insertion, follow-up at 1 year and as clinically needed
+    - Shunt radionuclide studies: Used to confirm distal obstruction
+- ## Top Differential Diagnoses
+  
+  
+    - Shunt failure with normal ventricle size or lack of interstitial edema
+    - Noncompliant (slit) ventricle syndrome
+    - Acquired Chiari 1 malformation/tonsillar ectopia
+- ## Pathology
+  
+  
+    - Obstructive HCP: Secondary to physical blockage by tumor, adhesions, cyst
+    - Communicating HCP: Secondary to ↓ CSF absorption across arachnoid granulations
+- ## Clinical Issues
+  
+  
+    - Older children/adults: Headache, vomiting, lethargy, seizure, neurocognitive symptoms
+    - Infants: Bulging fontanelle, ↑ head circumference, irritability, lethargy
+- ## Diagnostic Checklist
+  
+  
+    - Shunt + headache not always shunt failure
+    - Confirm programmable shunt valve setting after MR
+    - Compare current CT with prior studies to detect subtle changes in ventricle size
+
+# TERMINOLOGY
+
+- ## Abbreviations
+  
+  
+    - Shunt types: Ventriculoperitoneal (VP), ventriculoatrial (VA), ventriculopleural (VPL), lumboperitoneal (LP)
+- ## Definitions
+  
+  
+    - Ventriculomegaly
+          - General term for enlargement of cerebral ventricles
+    - Hydrocephalus (HCP)
+          - Enlargement of cerebral ventricles secondary to abnormal CSF formation, flow, or absorption resulting in ↑ CSF volume
+                  - Subset of ventriculomegaly
+                  - Onset over days (acute), weeks (subacute), or months to years (chronic)
+
+# IMAGING
+
+- ## General Features
+  
+  
+    - ### Best diagnostic clue
+      
+      
+          - Shunt failure: Dilated ventricles + edema ("blurring") around ventricles and along catheter, reservoir
+    - ### Location
+      
+      
+          - VP shunt common; VA and VPL used rarely unless VP contraindicated
+    - ### Size
+      
+      
+          - Ventricular size is relative → ventriculomegaly, may indicate shunt failure in one patient and be stable finding in another
+                  - Change in ventricular size in individual patient probably significant
+                  - Conversely, some patients manifest shunt failure with minimal to no change in ventricular size
+          - Distal catheter must be sized long enough to permit somatic growth, prevent retraction out of abdomen or chest
+    - ### Morphology
+      
+      
+          - Shunt system components
+                  - Proximal catheter in ventricles, subarachnoid space, syrinx cavity, or thecal sac
+                  - Unidirectional valve prevents reflux into ventricles
+                  - Reservoir used to sample CSF, acutely relieve pressure
+                  - Distal catheter tunneled through subcutaneous tissues → tip in peritoneal cavity, cardiac atrium, or pleural cavity
+- ## Radiographic Findings
+  
+  
+    - ### Radiography
+      
+      
+          - Evaluate shunt catheter system integrity
+                  - Shunt fracture, separation, migration
+                  - Distal catheter may retract out of abdomen if significant somatic growth since shunt placement
+- ## Fluoroscopic Findings
+  
+  
+    - Contrast shuntogram to define site of obstruction (historical interest)
+- ## CT Findings
+  
+  
+    - ### NECT
+      
+      
+          - Ventricular dilatation (diffuse or loculated)
+                  - Isolated ventricle after infection, hemorrhage → interventricular synechia
+                  - Periventricular interstitial edema ("blurred" ventricle margins) → acute HCP
+          - Small, slit ventricles → noncompliant ventricle syndrome, chronic overdrainage
+          - ± subdural hematoma (CSF overdrainage)
+    - ### CECT
+      
+      
+          - ± ependymal enhancement (chemical or infectious ventriculitis)
+          - Detection of intracranial abscess or empyema as complication of shunt infection
+- ## MR Findings
+  
+  
+    - ### T1WI
+      
+      
+          - Assess ventricular size, characterize brain anatomy
+    - ### T2WI
+      
+      
+          - ± interstitial periventricular edema → acute shunt failure
+    - ### FLAIR
+      
+      
+          - Interstitial edema more conspicuous than on T1WI or T2WI
+    - ### T2* GRE
+      
+      
+          - Assess hemorrhagic shunt tracts, interventricular hemorrhage
+    - ### DWI
+      
+      
+          - ↑ diffusivity with interstitial edema
+    - ### T1WI C+
+      
+      
+          - ± enhancement with ventriculitis, abscess, neoplasm
+          - Pachymeningeal enhancement due to low intracranial pressure (ICP)
+    - ### MRA
+      
+      
+          - Stretched, displaced arteries around dilated ventricles secondary to ventriculomegaly
+    - ### MRV
+      
+      
+          - Venous thrombosis may precede HCP or follow shunting
+                  - Leads to ↑ intraventricular/ICP
+    - ### MR cine
+      
+      
+          - Evaluate patency of normal CSF pathways, 3rd ventriculostomy
+    - ### MRS
+      
+      
+          - Small lactate resonances detected in CSF of up to 20% of HCP, even if HCP absent
+- ## Ultrasonographic Findings
+  
+  
+    - ### Grayscale ultrasound
+      
+      
+          - Useful in neonates for serial assessment of ventricular size (requires open fontanelle)
+    - ### Pulsed Doppler
+      
+      
+          - Resistive indices increase with shunt obstruction, ↑ ICP
+    - ### Color Doppler
+      
+      
+          - Research studies document flow within shunt tubing, aqueduct
+- ## Nonvascular Interventions
+  
+  
+    - Interventricular contrast injection through shunt + NECT→ detect ventricular isolation needing additional catheter
+- ## Nuclear Medicine Findings
+  
+  
+    - ### PET
+      
+      
+          - Cerebral vascular reserve (CVR) measurement may aid selection of shunt candidates
+    - Shunt radionuclide studies
+          - Radiotracer injected into shunt reservoir; serial imaging to document timing of radiotracer egress from distal catheter tip
+          - Used to confirm distal obstruction
+- ## Imaging Recommendations
+  
+  
+    - ### Best imaging tool
+      
+      
+          - Brain NECT to assess for acute ventricular size change
+          - Fast MR protocols (HASTE, SSFSE) used in many centers with 24-hour MR availability to avoid cumulative radiation exposure
+    - ### Protocol advice
+      
+      
+          - Brain CT or MR to evaluate ventricle size
+          - Baseline CT/MR following shunt insertion, follow-up at 1 year and as clinically needed
+          - Plain film shunt series to identify mechanical shunt fracture or disconnection
+
+# DIFFERENTIAL DIAGNOSIS
+
+- ## Shunt Failure With Normal Ventricle Size or Lack of Interstitial Edema
+  
+  
+    - Look for fluid along shunt catheter or reservoir as only sign of malfunction
+    - May require diagnosis on clinical grounds
+- ## Noncompliant (Slit) Ventricle Syndrome
+  
+  
+    - Usually older child (shunted in infancy)
+    - Small ventricles + intermittent signs of shunt obstruction
+    - Ventricles normal/small, even if shunt malfunctioning
+    - May be caused by shunt-induced sutural ossification or poor ventricular compliance
+- ## Acquired Chiari 1 Malformation/Tonsillar Ectopia
+  
+  
+    - Functioning LP shunt produces tonsillar descent through foramen magnum
+    - More common with valveless systems
+    - Not always symptomatic
+
+# PATHOLOGY
+
+- ## General Features
+  
+  
+    - ### Etiology
+      
+      
+          - Normal CSF production = 0.2-0.7 mL/minute; 250 (child) to 500 mL (adult) per 24-hour period
+                  - Majority of CSF produced by choroid plexus, resorbed by arachnoid granulations
+                  - Capacity of ventricles in healthy adult = 25 mL
+                  - Total CSF volume (adult) = 125 mL
+          - Impairment of CSF circulation
+                  - Obstructive
+                            - Usually at narrowest points in CSF circulation (aqueduct, foramina of Monro)
+                            - Tumor, web/synechia, congenital aqueductal stenosis
+                  - Inadequate reabsorption across arachnoid granulations into venous sinuses
+                            - Arachnoid granulations "clogged" after hemorrhage, inflammation
+                            - Diminished pressure gradient from subarachnoid space to venous sinuses secondary to venous hypertension
+                            - Impaired CSF absorption → CSF accumulation, ↑ ICP
+          - CSF shunt establishes accessory drainage pathway to bypass obstructed natural CSF flow pathways
+                  - Restores or maintains normal ICP
+          - Each shunt, valve, device carries its own set of complications
+                  - All types → material degradation/fatigue, mechanical stress (especially craniocervical junction, inferior ribs)
+                  - VP → abdominal complications (CSF pseudocyst, ascites, bowel perforation)
+                  - VPL → symptomatic pleural effusion
+                  - VA → shunt nephritis, cor pulmonale, pulmonary embolus
+                  - LP → arachnoiditis, cerebellar tonsillar herniation, high catheter migration rate
+                  - Programmable shunt → unintentional reprogram during MR
+                  - Shuntless CSF diversion → 3rd ventriculostomy, 4th ventricle outlet fenestration
+                  - Silicone allergy → allergic response, catheter occlusion with debris
+                  - Antisiphon devices → obstruction by capsule formation
+                  - 1-piece shunt → ↓ catheter obstruction rate, ↑ slit ventricle/subdural hemorrhage rate
+                  - Flanged catheters → ↑ incidence of proximal occlusion
+                  - Internal 3rd ventricle to spinal SAS (Lapras catheter) → no external access, no method to check flow
+                  - Flow vs. pressure regulation
+                            - Pressure-regulating shunts prone to overdrainage
+                            - Flow-regulating valves prone to obstruction
+                            - Magnetic valves commonly used but cause artifact on MR and require resetting after MR
+          - Cerebral atrophy, focal destructive lesions also produce ↑ CSF spaces, but these are not HCP
+                  - Loss of cerebral tissue → vacant space passively filled with CSF
+                  - Not result of hydrodynamic disorder → not HCP
+    - ### Associated abnormalities
+      
+      
+          - Shunts placed with CSF blood/protein > 1 g/dL prone to early blockage, failure
+          - Shunt infection
+          - Ventricular loculation or isolation
+          - Overshunting
+- ## Gross Pathologic & Surgical Features
+  
+  
+    - Ventricular ependymal adhesions (scar)
+    - Extracranial shunt tubing calcification
+- ## Microscopic Features
+  
+  
+    - Gliosis along intracranial shunt tract
+
+# CLINICAL ISSUES
+
+- ## Presentation
+  
+  
+    - ### Most common signs/symptoms
+      
+      
+          - Children, adults
+                  - Headache, vomiting, lethargy, seizure
+                  - Neuropsychologic, cognitive, or behavioral
+          - Infants
+                  - Bulging fontanelle, ↑ head circumference, irritability, lethargy
+    - ### Clinical profile
+      
+      
+          - Depends on underlying clinical diagnosis necessitating CSF diversion, number of previous shunts, complications
+- ## Demographics
+  
+  
+    - ### Age
+      
+      
+          - 1st weeks of life for myelomeningocele, congenital HCP
+          - Older age at 1st shunting for HCP following trauma, meningitis, tumor
+    - ### Epidemiology
+      
+      
+          - 160,000 shunts implanted each year worldwide
+          - CSF shunts in USA ~ 125,000 total
+                  - 33,000 placed per year (~ 45-50% revisions)
+- ## Natural History & Prognosis
+  
+  
+    - After shunting, 70% either normal or relatively normal intelligence (if no complications or associated anomalies)
+    - Epilepsy incidence up to 47% if shunt follows meningitis, hemorrhage
+    - HCP mortality depends on shunt complication: Malfunction (30%), infection (20%), pulmonary embolus (7%)
+    - Acute shunt obstruction in shunt-dependent patients may lead to death
+    - Majority of shunt revisions occur during first 6 months after shunt placement
+          - Age at time of shunt surgery, previous shunt surgery, etiology of HCP, and HCP type independently associated with incidence of shunt revision
+          - 50% of patients need multiple revisions, progressively shorter time interval to next failure
+- ## Treatment
+  
+  
+    - Shunt revision
+          - Replace intraventricular component/valve for proximal obstruction
+          - Alter valve pressure setting/type if over- or underdraining
+                  - Programmable shunt valves permit transcutaneous adjustment of pressure setting
+          - Lengthen distal shunt as child grows
+    - 3rd ventriculostomy to avoid indwelling shunt if blockage is distal to 3rd ventricle
+    - Subtemporal decompression or 3rd ventriculostomy for noncompliant ventricle syndrome
+    - Laparoscopic or open abdominal procedure for distal obstruction related to CSF pseudocyst
+
+# DIAGNOSTIC CHECKLIST
+
+- ## Consider
+  
+  
+    - Shunt + headache does not always mean shunt failure
+          - Consider sinusitis, trauma, sinovenous thrombosis, viral infection
+    - Confirm programmable shunt valve setting after MR
+    - Plain film shunt series has extremely low yield in absence of clinical evidence for mechanical shunt failure
+- ## Image Interpretation Pearls
+  
+  
+    - Compare with prior studies to detect subtle ventricular size changes
+    - Poor ventricular compliance may prevent change in ventricular size despite florid clinical shunt failure
+    - Fluid tracking along shunt may be only sign of failure; possible even if ventricles normal or unchanged size
+
+ 5eea2e07-bb80-48db-ad5d-a0c14176d17f
+
+## References
+
+# Selected References
+
+1. [Fowler JB et al: Ventriculoperitoneal shunt, 2020](http://www.ncbi.nlm.nih.gov/pubmed/?term=29083724%5Bpmid%5D)
+1. [Kaestner S et al: Revision surgery following CSF shunt insertion: how often could it be avoided? Acta Neurochir (Wien). 162(1):9-14, 2020](http://www.ncbi.nlm.nih.gov/pubmed/?term=31667581%5Bpmid%5D)
+1. [Mohammad SA et al: The value of CSF flow studies in the management of CSF disorders in children: a pictorial review. Insights Imaging. 10(1):3, 2019](http://www.ncbi.nlm.nih.gov/pubmed/?term=30689061%5Bpmid%5D)
+1. [Ezzat AAM et al: Migration of the distal catheter of ventriculoperitoneal shunts in pediatric age group: case series. World Neurosurg. 119:e131-7, 2018](http://www.ncbi.nlm.nih.gov/pubmed/?term=30031953%5Bpmid%5D)
+1. [Kraemer MR et al: Overdrainage-related ependymal bands: a postulated cause of proximal shunt obstruction. J Neurosurg Pediatr. 1-11, 2018](http://www.ncbi.nlm.nih.gov/pubmed/?term=30117791%5Bpmid%5D)
+1. [Ros B et al: Shunt overdrainage syndrome: review of the literature. Neurosurg Rev. 41(4):969-81, 2018](http://www.ncbi.nlm.nih.gov/pubmed/?term=28352945%5Bpmid%5D)
+1. [Hanak BW et al: Cerebrospinal fluid shunting complications in children. Pediatr Neurosurg. 52(6):381-400, 2017](http://www.ncbi.nlm.nih.gov/pubmed/?term=28249297%5Bpmid%5D)
+1. [Rinker EK et al: CSF shunt complications: what the abdominal imager needs to know. Abdom Imaging. 40(6):2030-40, 2015](http://www.ncbi.nlm.nih.gov/pubmed/?term=25652954%5Bpmid%5D)
+1. [Symss NP et al: Is there an ideal shunt? A panoramic view of 110 years in CSF diversions and shunt systems used for the treatment of hydrocephalus: from historical events to current trends. Childs Nerv Syst. 31(2):191-202, 2015](http://www.ncbi.nlm.nih.gov/pubmed/?term=25547875%5Bpmid%5D)
+1. [Koktekir E et al: Resolution of papilledema after endoscopic third ventriculostomy versus cerebrospinal fluid shunting in hydrocephalus: a comparative study. J Neurosurg. 120(6):1465-70, 2014](http://www.ncbi.nlm.nih.gov/pubmed/?term=24678778%5Bpmid%5D)
+1. [Bateman GA: Hypertensive slit ventricle syndrome: pseudotumor cerebri with a malfunctioning shunt? J Neurosurg. 119(6):1503-10, 2013](http://www.ncbi.nlm.nih.gov/pubmed/?term=23991845%5Bpmid%5D)
+1. [Rasul FT et al: Is endoscopic third ventriculostomy superior to shunts in patients with non-communicating hydrocephalus? A systematic review and meta-analysis of the evidence. Acta Neurochir (Wien). 155(5):883-9, 2013](http://www.ncbi.nlm.nih.gov/pubmed/?term=23456239%5Bpmid%5D)
+1. [Symss NP et al: Theories of cerebrospinal fluid dynamics and hydrocephalus: historical trend. J Neurosurg Pediatr. 11(2):170-7, 2013](http://www.ncbi.nlm.nih.gov/pubmed/?term=23215851%5Bpmid%5D)
+1. [Robinson S: Neonatal posthemorrhagic hydrocephalus from prematurity: pathophysiology and current treatment concepts. J Neurosurg Pediatr. 9(3):242-58, 2012](http://www.ncbi.nlm.nih.gov/pubmed/?term=22380952%5Bpmid%5D)
+1. [Sivaganesan A et al: Neuroimaging of ventriculoperitoneal shunt complications in children. Pediatr Radiol. 42(9):1029-46, 2012](http://www.ncbi.nlm.nih.gov/pubmed/?term=22740019%5Bpmid%5D)
+1. [Chan M et al: Prediction of ventriculoperitoneal shunt dependency in patients with aneurysmal subarachnoid hemorrhage. J Neurosurg. 110(1):44-9, 2009](http://www.ncbi.nlm.nih.gov/pubmed/?term=18950263%5Bpmid%5D)
+1. [Peraud A et al: Decompensated hydrocephalus causing syringomyelia and tetraparesis: a case report. Childs Nerv Syst. 25(2):263-6, 2009](http://www.ncbi.nlm.nih.gov/pubmed/?term=18979102%5Bpmid%5D)
+1. [Willis B et al: Ventricular reservoirs and ventriculoperitoneal shunts for premature infants with posthemorrhagic hydrocephalus: an institutional experience. J Neurosurg Pediatr. 3(2):94-100, 2009](http://www.ncbi.nlm.nih.gov/pubmed/?term=19278306%5Bpmid%5D)
+1. [Dusick JR et al: Success and complication rates of endoscopic third ventriculostomy for adult hydrocephalus: a series of 108 patients. Surg Neurol. 69(1):5-15, 2008](http://www.ncbi.nlm.nih.gov/pubmed/?term=18054606%5Bpmid%5D)
+1. [Ellis MJ et al: Treatment of recurrent ventriculoperitoneal shunt failure associated with persistent cerebrospinal fluid eosinophilia and latex allergy by use of an "extracted" shunt. J Neurosurg Pediatr. 1(3):237-9, 2008](http://www.ncbi.nlm.nih.gov/pubmed/?term=18352769%5Bpmid%5D)
+1. [James HE et al: Management of complicated shunt infections: a clinical report. J Neurosurg Pediatr. 1(3):223-8, 2008](http://www.ncbi.nlm.nih.gov/pubmed/?term=18352767%5Bpmid%5D)
+1. [Martínez-Lage JF et al: Acute cholecystitis complicating ventriculo-peritoneal shunting: report of a case and review of the literature. Childs Nerv Syst. 24(6):777-9, 2008](http://www.ncbi.nlm.nih.gov/pubmed/?term=18365208%5Bpmid%5D)
+1. [Nfonsam V et al: Laparoscopic management of distal ventriculoperitoneal shunt complications. Surg Endosc. 22(8):1866-70, 2008](http://www.ncbi.nlm.nih.gov/pubmed/?term=18175181%5Bpmid%5D)
+1. [Riffaud L et al: Acquired Chiari I malformation and syringomyelia after valveless lumboperitoneal shunt in infancy. Pediatr Neurosurg. 44(3):229-33, 2008](http://www.ncbi.nlm.nih.gov/pubmed/?term=18354264%5Bpmid%5D)
+1. [Liao YJ et al: Intracranial hypotension caused by leakage of cerebrospinal fluid from the thecal sac after lumboperitoneal shunt placement. Case report. J Neurosurg. 107(1):173-7, 2007](http://www.ncbi.nlm.nih.gov/pubmed/?term=17639890%5Bpmid%5D)
+1. [Tseng JS et al: Motor neuron disease-like syndrome secondary to trapped fourth ventricle and obstruction of cerebrospinal fluid pathway. Clin Neurol Neurosurg. 109(4):383-7, 2007](http://www.ncbi.nlm.nih.gov/pubmed/?term=17275996%5Bpmid%5D)
+1. [Woodworth G et al: Prior CSF shunting increases the risk of endoscopic third ventriculostomy failure in the treatment of obstructive hydrocephalus in adults. Neurol Res. 29(1):27-31, 2007](http://www.ncbi.nlm.nih.gov/pubmed/?term=17427271%5Bpmid%5D)
+1. [Di Rocco C et al: Shunts vs endoscopic third ventriculostomy in infants: are there different types and/or rates of complications? A review. Childs Nerv Syst. 22(12):1573-89, 2006](http://www.ncbi.nlm.nih.gov/pubmed/?term=17053941%5Bpmid%5D)
+1. [Winston KR et al: CSF shunt failure with stable normal ventricular size. Pediatr Neurosurg. 42(3):151-5, 2006](http://www.ncbi.nlm.nih.gov/pubmed/?term=16636615%5Bpmid%5D)
+1. [Zamponi N et al: Bobble head doll syndrome in a child with a third ventricular cyst and hydrocephalus. Childs Nerv Syst. 21(5):350-4, 2005](http://www.ncbi.nlm.nih.gov/pubmed/?term=15449088%5Bpmid%5D)
+1. [Arnell K et al: Distal catheter obstruction from non-infectious cause in ventriculo-peritoneal shunted children. Eur J Pediatr Surg. 14(4):245-9, 2004](http://www.ncbi.nlm.nih.gov/pubmed/?term=15343464%5Bpmid%5D)
+1. [Blount JP et al: Sports and pediatric cerebrospinal fluid shunts: who can play? Neurosurgery. 54(5):1190-6; discussion 1196-8, 2004](http://www.ncbi.nlm.nih.gov/pubmed/?term=15113475%5Bpmid%5D)
+1. [Fewel ME et al: Migration of distal ventriculoperitoneal shunt catheter into the heart. Case report and review of the literature. J Neurosurg. 100(2 Suppl Pediatrics):206-11, 2004](http://www.ncbi.nlm.nih.gov/pubmed/?term=14758952%5Bpmid%5D)
+1. [Hashimoto M et al: A case of abdominal CSF pseudocyst associated with silicone allergy. Childs Nerv Syst. 20(10):761-4, 2004](http://www.ncbi.nlm.nih.gov/pubmed/?term=14999512%5Bpmid%5D)
+1. [Sgouros S et al: An investigation of structural degradation of cerebrospinal fluid shunt valves performed using scanning electron microscopy and energy-dispersive x-ray microanalysis. J Neurosurg. 100(3):534-40, 2004](http://www.ncbi.nlm.nih.gov/pubmed/?term=15035291%5Bpmid%5D)
+1. [Tuli S et al: Predictors of death in pediatric patients requiring cerebrospinal fluid shunts. J Neurosurg. 100(5 Suppl Pediatrics):442-6, 2004](http://www.ncbi.nlm.nih.gov/pubmed/?term=15287452%5Bpmid%5D)
+1. [Villarejo FJ et al: Cerebral fluid edema: an unusual complication of ventriculoperitoneal shunts. Childs Nerv Syst. 20(3):195-8, 2004](http://www.ncbi.nlm.nih.gov/pubmed/?term=14749945%5Bpmid%5D)
+1. [Braun KP et al: 1H magnetic resonance spectroscopy in human hydrocephalus. J Magn Reson Imaging. 17(3):291-9, 2003](http://www.ncbi.nlm.nih.gov/pubmed/?term=12594718%5Bpmid%5D)
+1. [Krassoudakis A et al: Ventriculoperitoneal shunting complicated with cerebrospinal fluid pseudocyst and acute appendicitis. Minerva Pediatr. 54(4):321-3, 2002](http://www.ncbi.nlm.nih.gov/pubmed/?term=12131868%5Bpmid%5D)
+1. [Oh A et al: Laparoscopic repositioning of a ventriculo-peritoneal catheter tip for a sterile abdominal cerebrospinal fluid (CSF) pseudocyst. Surg Endosc. 15(5):518, 2001](http://www.ncbi.nlm.nih.gov/pubmed/?term=11353974%5Bpmid%5D)
+1. [Drake JM et al: CSF shunts 50 years on--past, present and future. Childs Nerv Syst. 16(10-11):800-4, 2000](http://www.ncbi.nlm.nih.gov/pubmed/?term=11151733%5Bpmid%5D)
+1. [Tuli S et al: Risk factors for repeated cerebrospinal shunt failures in pediatric patients with hydrocephalus. J Neurosurg. 92(1):31-8, 2000](http://www.ncbi.nlm.nih.gov/pubmed/?term=10616079%5Bpmid%5D)
+1. [Lee TT et al: Unique clinical presentation of pediatric shunt malfunction. Pediatr Neurosurg. 30(3):122-6, 1999](http://www.ncbi.nlm.nih.gov/pubmed/?term=10352413%5Bpmid%5D)
+1. [Salomão JF et al: Abdominal pseudocysts complicating CSF shunting in infants and children. Report of 18 cases. Pediatr Neurosurg. 31(5):274-8, 1999](http://www.ncbi.nlm.nih.gov/pubmed/?term=10681683%5Bpmid%5D)
+
+
+## Images
+
+
+### Selected Images
+
+![Lateral skull radiograph of acute ventriculoperitoneal (VP) shunt failure from a plain radiograph shunt series demonstrates a mechanical shunt catheter disconnection <img src='/img/arrows/WS.png'/> between the programmable valve and the reservoir.](images/app.statdx.com_image_thumbnail_da023baa-4d46-4fb6-8717-a85638b77ef6_annotated_true_size_900_quality_90_971d1d2d_20251018T164445Z.jpg)
+*Lateral skull radiograph of acute ventriculoperitoneal (VP) shunt failure from a plain radiograph shunt series demonstrates a mechanical shunt catheter disconnection <img src='/img/arrows/WS.png'/> between the programmable valve and the reservoir.*
+
+![Lateral skull radiograph of acute ventriculoperitoneal (VP) shunt failure from a plain radiograph shunt series demonstrates a mechanical shunt catheter disconnection <img src='/img/arrows/WS.png'/> between the programmable valve and the reservoir.](images/app.statdx.com_image_thumbnail_da023baa-4d46-4fb6-8717-a85638b77ef6_size_174_quality_85_e8d9943b_20251018T165055Z.jpg)
+*Lateral skull radiograph of acute ventriculoperitoneal (VP) shunt failure from a plain radiograph shunt series demonstrates a mechanical shunt catheter disconnection <img src='/img/arrows/WS.png'/> between the programmable valve and the reservoir.*
+
+![Axial bone CT in the same patient reveals the mechanical catheter disconnection <img src='/img/arrows/WS.png'/> between the reservoir and the programmable shunt valve. This finding had not appeared on the most recent comparison CT scan (not shown).](images/app.statdx.com_image_thumbnail_87340bd2-1fa0-4463-95b4-8a835e5b6f25_annotated_true_size_900_quality_90_48f77c00_20251018T164445Z.jpg)
+*Axial bone CT in the same patient reveals the mechanical catheter disconnection <img src='/img/arrows/WS.png'/> between the reservoir and the programmable shunt valve. This finding had not appeared on the most recent comparison CT scan (not shown).*
+
+![AP radiograph from a shunt series demonstrates intracardiac migration of the VP shunt catheter with the tip residing in the right interlobar pulmonary artery.](images/app.statdx.com_image_thumbnail_2c7ef1d1-3464-480a-8b31-bd93676ca33f_annotated_true_size_900_quality_90_4b19d26a_20251018T164445Z.jpg)
+*AP radiograph from a shunt series demonstrates intracardiac migration of the VP shunt catheter with the tip residing in the right interlobar pulmonary artery.*
+
+![AP radiograph of the pelvis in a 4 year old with a VP shunt who presented with left scrotal swelling demonstrates a coiled distal shunt catheter <img src='/img/arrows/CS.png'/> in the left scrotum. The migration of the catheter to the scrotum is due to a patent processus vaginalis.](images/app.statdx.com_image_thumbnail_54dcd3b6-9e3a-4edb-8a6d-4aa25c8efc4f_annotated_true_size_900_quality_90_b264cf48_20251018T164445Z.jpg)
+*AP radiograph of the pelvis in a 4 year old with a VP shunt who presented with left scrotal swelling demonstrates a coiled distal shunt catheter <img src='/img/arrows/CS.png'/> in the left scrotum. The migration of the catheter to the scrotum is due to a patent processus vaginalis.*
+
+![Axial NECT depicts symmetric interstitial edema within the periventricular white matter. Ventricular size is significantly larger than demonstrated on a prior CT (not shown), supporting the diagnosis of acute shunt failure.](images/app.statdx.com_image_thumbnail_55b2c8c6-2eb1-42ee-b735-b6c0f9cb116d_annotated_true_size_900_quality_90_2a57efea_20251018T164445Z.jpg)
+*Axial NECT depicts symmetric interstitial edema within the periventricular white matter. Ventricular size is significantly larger than demonstrated on a prior CT (not shown), supporting the diagnosis of acute shunt failure.*
+
+![Axial NECT in a patient with VP shunt <img src='/img/arrows/CS.png'/> who presented with severe headaches shows collapsed lateral ventricles <img src='/img/arrows/CC.png'/>. Slit ventricle syndrome presents as severe headaches due to noncompliant ventricles and should not be confused with radiologic slit ventricles.](images/app.statdx.com_image_thumbnail_650743ea-956f-46a3-93a0-873aa0cbddd1_annotated_true_size_900_quality_90_dbd0eceb_20251018T164445Z.jpg)
+*Axial NECT in a patient with VP shunt <img src='/img/arrows/CS.png'/> who presented with severe headaches shows collapsed lateral ventricles <img src='/img/arrows/CC.png'/>. Slit ventricle syndrome presents as severe headaches due to noncompliant ventricles and should not be confused with radiologic slit ventricles.*
+
+![Coronal bone CT demonstrates fracture or disconnection of the ventricular catheter <img src='/img/arrows/WS.png'/> from the reservoir <img src='/img/arrows/WO.png'/> resulting in clinical shunt failure (larger ventricles on NECT).](images/app.statdx.com_image_thumbnail_b7a01263-8d5d-4bcd-a819-2e6b04c35eef_annotated_true_size_900_quality_90_e668546f_20251018T164445Z.jpg)
+*Coronal bone CT demonstrates fracture or disconnection of the ventricular catheter <img src='/img/arrows/WS.png'/> from the reservoir <img src='/img/arrows/WO.png'/> resulting in clinical shunt failure (larger ventricles on NECT).*
+
+![Axial NECT following bilateral ventricular catheter placement in a patient with severe hydrocephalus (HCP) and brain atrophy reveals development of a large left subdural hematoma <img src='/img/arrows/WS.png'/> following VP shunting.](images/app.statdx.com_image_thumbnail_763808e4-56c2-4987-afc2-ab975e4d6708_annotated_true_size_900_quality_90_269bc444_20251018T164445Z.jpg)
+*Axial NECT following bilateral ventricular catheter placement in a patient with severe hydrocephalus (HCP) and brain atrophy reveals development of a large left subdural hematoma <img src='/img/arrows/WS.png'/> following VP shunting.*
+
+![Axial NECT in a patient with HCP presenting with distal VP shunt failure shows the peritoneal catheter tip <img src='/img/arrows/WS.png'/> within a loculated pelvic fluid collection (CSF pseudocyst <img src='/img/arrows/WO.png'/>).](images/app.statdx.com_image_thumbnail_8a8dd95c-3f84-4e93-a845-7b63366fa374_annotated_true_size_900_quality_90_0d3b647c_20251018T164445Z.jpg)
+*Axial NECT in a patient with HCP presenting with distal VP shunt failure shows the peritoneal catheter tip <img src='/img/arrows/WS.png'/> within a loculated pelvic fluid collection (CSF pseudocyst <img src='/img/arrows/WO.png'/>).*
+
+![Frontal cisternogram-radionuclide shuntogram examination performed after injecting the shunt valve reservoir reveals no spillage from the distal catheter <img src='/img/arrows/BS.png'/> after 10 minutes. Further delayed imaging (not shown) confirmed absence of spillage from the catheter, substantiating distal shunt obstruction.](images/app.statdx.com_image_thumbnail_9399b93d-ebc2-488c-a1cd-7360eecb3d04_annotated_true_size_900_quality_90_cbfc04fc_20251018T164452Z.jpg)
+*Frontal cisternogram-radionuclide shuntogram examination performed after injecting the shunt valve reservoir reveals no spillage from the distal catheter <img src='/img/arrows/BS.png'/> after 10 minutes. Further delayed imaging (not shown) confirmed absence of spillage from the catheter, substantiating distal shunt obstruction.*
+
+
+### Additional Images
+
+![Lateral radiograph from a plain film shunt series in an infant with acute shunt failure demonstrates that the ventricular catheter has pulled out of the head and is lying along the distal catheter within the scalp (tip <img src='/img/arrows/WS.png'/>).](images/app.statdx.com_image_thumbnail_7fa2b6f1-07c9-45fc-9a29-d79045ac436a_annotated_true_size_900_quality_90_5a7ac107_20251018T164455Z.jpg)
+*Lateral radiograph from a plain film shunt series in an infant with acute shunt failure demonstrates that the ventricular catheter has pulled out of the head and is lying along the distal catheter within the scalp (tip <img src='/img/arrows/WS.png'/>).*
+
+![AP radiograph in a patient with chest pain after ventriculopleural (VPL) shunt placement depicts a right pneumothorax <img src='/img/arrows/BS.png'/> related to the shunt placement. Note the abandoned catheter fragment <img src='/img/arrows/WS.png'/> from a prior VP shunt system.](images/app.statdx.com_image_thumbnail_5448724e-86c6-4f45-80dc-1f1856863864_annotated_true_size_900_quality_90_1a2e5733_20251018T164455Z.jpg)
+*AP radiograph in a patient with chest pain after ventriculopleural (VPL) shunt placement depicts a right pneumothorax <img src='/img/arrows/BS.png'/> related to the shunt placement. Note the abandoned catheter fragment <img src='/img/arrows/WS.png'/> from a prior VP shunt system.*
+
+![AP radiography indicates a large left pleural effusion <img src='/img/arrows/WS.png'/> in a symptomatic child with a left VPL shunt catheter <img src='/img/arrows/WO.png'/>.](images/app.statdx.com_image_thumbnail_2e0678e8-e16c-4859-b94f-b85ec399af77_annotated_true_size_900_quality_90_a2293a04_20251018T164458Z.jpg)
+*AP radiography indicates a large left pleural effusion <img src='/img/arrows/WS.png'/> in a symptomatic child with a left VPL shunt catheter <img src='/img/arrows/WO.png'/>.*
+
+![Axial CECT of the pelvis in a shunted patient with HCP presenting with acute shunt failure, fever, and abdominal pain shows the peritoneal VP shunt catheter <img src='/img/arrows/WS.png'/> residing within a rim-enhancing pelvic fluid collection that represents a pelvic abscess secondary to perforated appendicitis.](images/app.statdx.com_image_thumbnail_fbf68223-80c5-46c7-957f-ca81995ba5d9_annotated_true_size_900_quality_90_1980ef02_20251018T164458Z.jpg)
+*Axial CECT of the pelvis in a shunted patient with HCP presenting with acute shunt failure, fever, and abdominal pain shows the peritoneal VP shunt catheter <img src='/img/arrows/WS.png'/> residing within a rim-enhancing pelvic fluid collection that represents a pelvic abscess secondary to perforated appendicitis.*
+
+![Axial NECT in a patient with HCP presenting with shunt failure shows the peritoneal VP shunt catheter tip <img src='/img/arrows/WS.png'/> residing within a large loculated pelvic fluid collection (CSF pseudocyst).](images/app.statdx.com_image_thumbnail_d9b08852-2e8c-4bef-adcb-04e10e0e34c3_annotated_true_size_900_quality_90_3b3e0372_20251018T164459Z.jpg)
+*Axial NECT in a patient with HCP presenting with shunt failure shows the peritoneal VP shunt catheter tip <img src='/img/arrows/WS.png'/> residing within a large loculated pelvic fluid collection (CSF pseudocyst).*
+
+![Axial T2 MR depicts reservoir <img src='/img/arrows/WC.png'/>, shunt tubing <img src='/img/arrows/WS.png'/>, collapsed left lateral ventricle, and dilated isolated right lateral ventricle with associated interstitial transependymal edema <img src='/img/arrows/WO.png'/>.](images/app.statdx.com_image_thumbnail_f7ebef35-a2fe-4035-a785-7ff1d2c028a3_annotated_true_size_900_quality_90_5f628e23_20251018T164459Z.jpg)
+*Axial T2 MR depicts reservoir <img src='/img/arrows/WC.png'/>, shunt tubing <img src='/img/arrows/WS.png'/>, collapsed left lateral ventricle, and dilated isolated right lateral ventricle with associated interstitial transependymal edema <img src='/img/arrows/WO.png'/>.*
+
+![Axial NECT in a patient with posthemorrhagic HCP following contrast injection through the right ventricular catheter shows contrast within the isolated right ventricle but no contrast transit into either the left lateral <img src='/img/arrows/WS.png'/> or 3rd ventricle <img src='/img/arrows/WO.png'/>.](images/app.statdx.com_image_thumbnail_3f761b63-67ef-4fd4-9e41-cf419010a054_annotated_true_size_900_quality_90_f0a5195a_20251018T164459Z.jpg)
+*Axial NECT in a patient with posthemorrhagic HCP following contrast injection through the right ventricular catheter shows contrast within the isolated right ventricle but no contrast transit into either the left lateral <img src='/img/arrows/WS.png'/> or 3rd ventricle <img src='/img/arrows/WO.png'/>.*
+
+![Axial FLAIR MR shows the sequelae of CSF overdrainage leading to bilateral subdural hematomas <img src='/img/arrows/WS.png'/> and ventricular collapse following shunt <img src='/img/arrows/WO.png'/> placement.](images/app.statdx.com_image_thumbnail_b3dfe4c0-3da8-447c-8f47-97a19528e184_annotated_true_size_900_quality_90_5a3db1f4_20251018T164503Z.jpg)
+*Axial FLAIR MR shows the sequelae of CSF overdrainage leading to bilateral subdural hematomas <img src='/img/arrows/WS.png'/> and ventricular collapse following shunt <img src='/img/arrows/WO.png'/> placement.*
+
+![Axial NECT of the brain shows development of bilateral subdural hematohygromata following shunting of severe obstructive HCP.](images/app.statdx.com_image_thumbnail_9b51a0ae-8574-43c8-ad66-c9d88ace4ebb_annotated_true_size_900_quality_90_135d3f47_20251018T164503Z.jpg)
+*Axial NECT of the brain shows development of bilateral subdural hematohygromata following shunting of severe obstructive HCP.*
+
+![Sagittal T1 C+ MR of a patient with intracranial hypotension shows obliteration of the suprasellar cistern, sagging fat midbrain with a closed angle between peduncles/pons <img src='/img/arrows/WS.png'/>, dural enhancement, and tonsillar descent.](images/app.statdx.com_image_thumbnail_fe076dec-96fa-4fe3-97cd-3c71abd81c09_annotated_true_size_900_quality_90_db1ac179_20251018T164503Z.jpg)
+*Sagittal T1 C+ MR of a patient with intracranial hypotension shows obliteration of the suprasellar cistern, sagging fat midbrain with a closed angle between peduncles/pons <img src='/img/arrows/WS.png'/>, dural enhancement, and tonsillar descent.*
+
+![AP radiography in patient with a VP shunt and acute shunt failure reveals fractured shunt tubing <img src='/img/arrows/WS.png'/>.](images/app.statdx.com_image_thumbnail_32aa4174-806c-4239-819d-49f88f817fa0_annotated_true_size_900_quality_90_8ab2e3f8_20251018T164503Z.jpg)
+*AP radiography in patient with a VP shunt and acute shunt failure reveals fractured shunt tubing <img src='/img/arrows/WS.png'/>.*
+
+![AP radiography shows a disconnected and caudally migrated peritoneal shunt catheter fragment looped within the pelvis.](images/app.statdx.com_image_thumbnail_0680af81-ef70-4c08-b3a5-c025ba031a43_annotated_true_size_900_quality_90_128e6046_20251018T164503Z.jpg)
+*AP radiography shows a disconnected and caudally migrated peritoneal shunt catheter fragment looped within the pelvis.*
+
+![AP radiography shows knotted abdominal shunt tubing. The tightly coiled appearance suggests an abnormal extraperitoneal placement of the shunt. Two shunts are present due to isolated ventricles.](images/app.statdx.com_image_thumbnail_0567b9fb-c5c2-4c12-8a0d-5af29bc02aaa_annotated_true_size_900_quality_90_d05e5b19_20251018T164504Z.jpg)
+*AP radiography shows knotted abdominal shunt tubing. The tightly coiled appearance suggests an abnormal extraperitoneal placement of the shunt. Two shunts are present due to isolated ventricles.*
+

docs_md/articles/demyelinating-diseases_e3ba880e-d924-4594-a6f4-c21c5f1f0ae7.md

@@ -0,0 +1,399 @@
+---
+title: "Demyelinating Diseases"
+docid: "e3ba880e-d924-4594-a6f4-c21c5f1f0ae7"
+authors:
+  - key: "838e1722-2479-4fbd-a5fe-d965980a1a2c"
+    value: "Blaise V. Jones, MD"
+breadcrumbs:
+  -
+    name: "Pediatrics"
+    slug: "pediatrics"
+    treeNodeId: "a915965c-d436-44cf-ae65-2f22e7246ea4"
+  -
+    name: "Diagnosis"
+    slug: "diagnosis"
+    treeNodeId: "2b5cea64-a083-489e-ac0c-ec14ba059026"
+  -
+    name: "Brain"
+    slug: "brain"
+    treeNodeId: "95caa0da-bc4f-4103-8551-f58d6e415781"
+  -
+    name: "Metabolic, Infectious, and Inflammatory Disorders"
+    slug: "metabolic-infectious-and-inflammat-"
+    treeNodeId: "ed178695-cb39-40bc-981d-d0031c835a98"
+  -
+    name: "Demyelinating Diseases"
+    slug: "demyelinating-diseases"
+    treeNodeId: null
+category: "Pediatrics"
+cmeTopicId: "273337e9-da4e-4caa-8a31-95fa5c11a1b9"
+documentVersionId: "5557de59-59d3-4508-b2dd-6913988c047d"
+imageCount: 23
+lastUpdated: "11/04/21"
+pageDescription: "Demyelinating Diseases"
+pageKeywords: "Pediatrics, Diagnosis, Brain, Metabolic, Infectious, and Inflammatory Disorders, Demyelinating Diseases"
+pageTitle: "Demyelinating Diseases | STATdx"
+enhancedTitle: "Demyelinating Diseases"
+type: "DX"
+references: true
+breadcrumbs:
+  - "Pediatrics"
+  - "Diagnosis"
+  - "Brain"
+  - "Metabolic, Infectious, and Inflammatory Disorders"
+  - "Demyelinating Diseases"
+---
+# KEY FACTS
+
+- ## Diagnostic Checklist
+  
+  
+    - Multiple sclerosis (MS)
+          - Demyelinating disease characterized by multiple lesions disseminated in time & space
+          - Brain lesions: Multiple T2- & FLAIR MR hyperintense foci, typically small (5-10 mm), ovoid, discrete, periventricular, & perpendicular to ventricular margins
+          - Optic neuritis (ON): Unilateral, short segment, intraorbital; myelitis: < 2 vertebrae in length, < 50% of cross-sectional area, typically peripheral
+    - Acute disseminated encephalomyelitis (ADEM)
+          - Acute demyelinating disease with encephalopathy, without NMOSD or anti-MOG associated antibodies
+          - Characteristically arises subsequent to infection (viral respiratory) or vaccination
+          - Brain: Ill-defined, larger T2-/FLAIR hyperintense lesions
+    - Neuromyelitis optica spectrum disorders (NMOSD)
+          - Inflammatory CNS disease caused by antibodies to aquaporin-4 (AQP-4) on astrocytic end feet
+          - ON & transverse myelitis predominate clinically
+          - Brain: Commonly periventricular but parallel to ependymal lining; area postrema involvement is classic
+          - ON: Bilateral, posterior predominant (including chiasm)
+          - Myelitis: Longitudinally extensive transverse myelitis (LETM) (> 3 vertebrae), > 50% of cord cross section, central
+    - Anti-MOG syndromes
+          - Acute demyelinating disease caused by antibodies to myelin oligodendrocyte glycoprotein (MOG)
+          - Extensive clinical overlap with ADEM & NMOSD; encephalopathy in younger patients, ON in older
+          - Brain: Similar to ADEM
+          - ON: Bilateral anterior predominant (including optic disc) with perineural enhancement
+          - Myelitis: LETM vs. short segment; conus involvement
+    - Lyme disease
+          - 11% develop neurologic manifestations
+          - May be accompanied by ON or other CN inflammation
+
+# TERMINOLOGY
+
+- ## Definitions
+  
+  
+    - Acquired demyelinating processes characterized by inflammation
+          - Multiple sclerosis (MS)
+                  - Demyelinating disease characterized by multiple lesions disseminated in time & space
+          - Acute disseminated encephalomyelitis (ADEM)
+                  - Acute demyelinating disease with encephalopathy, without NMOSD or anti-MOG-associated antibodies
+          - Neuromyelitis optica spectrum disorders (NMOSD)
+                  - Inflammatory CNS disease caused by antibodies to aquaporin-4 (AQP-4) on astrocytic end feet
+                  - Clinically characterized by optic neuritis & transverse myelitis
+          - Antimyelin oligodendrocyte glycoprotein (MOG) syndromes
+                  - Acute demyelinating disease caused by antibodies to MOG
+                  - Extensive clinical overlap with ADEM & NMOSD
+          - Lyme disease
+                  - CNS inflammation associated with *Borrelia burgdorferi* infection
+
+# IMAGING
+
+- ## General Features
+  
+  
+    - MS
+          - Brain: Multiple T2- & FLAIR MR hyperintense lesions, typically small (5-10 mm), ovoid, discrete
+                  - > 85% are periventricular: Callosal involvement, hemispheric white matter; perpendicular to ventricle margin in perivenular distribution
+                  - Variable enhancement: Presumed to reflect active demyelination
+                            - Nodular, diffuse, or ring-like
+                            - Can be mass-like: Tumefactive MS
+                  - Diffusion restriction in acute lesions
+                            - Diffusely abnormal ADC values
+                  - "Black holes" (due to axonal destruction) on T1 are much more likely to be seen in MS than ADEM
+          - Optic neuritis (ON): Unilateral, short length, intraorbital
+          - Myelitis: < 2 vertebral lengths, < 50% of cord cross section, cervical > thoracic
+    - ADEM
+          - Brain: Ill-defined larger T2-/FLAIR hyperintense lesions
+                  - Lesions are more likely to be diffuse & bilateral
+                  - Frequent brainstem & thalamic involvement
+          - ON: Less common; myelitis: Less common
+    - NMOSD
+          - Brain: May have extensive lesions
+                  - Commonly periventricular but parallel
+                  - Dorsal brainstem (especially area postrema)
+          - ON: Bilateral long segment
+                  - Posterior predominant, including chiasm
+          - Myelitis: Longitudinally extensive transverse myelitis (LETM) (> 3 segments), typically central & > 50% circumference
+    - Anti-MOG syndromes
+          - Brain: Similar in appearance to ADEM
+                  - Much less likely to involve corpus callosum
+          - ON: Bilateral long length with perineural enhancement
+                  - Anterior predominant, including optic disc
+          - Myelitis: LETM vs. short segment; conus often affected
+    - Lyme disease
+          - Presents as meningoencephalitis
+          - May be accompanied by ON or other cranial nerve inflammation; Bell palsy is characteristic
+- ## Imaging Recommendations
+  
+  
+    - ### Best imaging tool
+      
+      
+          - MR
+    - ### Protocol advice
+      
+      
+          - FLAIR MR imaging for detection
+                  - Postcontrast FLAIR may ↑ detection of meningeal disease
+          - Fat-saturated, high-resolution postcontrast orbital MR for assessment of ON
+          - Spine imaging with contrast & axial T2-weighted sequences
+
+# DIFFERENTIAL DIAGNOSIS
+
+- [Posterior Reversible Encephalopathy Syndrome](/document/acute-hypertensive-encephalopathy--/efc6f9c2-dad9-4eb8-bad2-421bfaf1ec57)
+    - Subcortical vasogenic edema associated with hypertension
+- [Viral Encephalitis](/document/acute-encephalitis/a45f63bb-c25b-481d-a001-9c520c58060b)
+    - Widely variable, but often affects white matter & deep gray nuclei
+- [Autoimmune-Mediated Vasculitis](/document/miscellaneous-vasculitis/5a4d4cbd-67e3-4722-8a44-8d411cbb98f0)
+    - Enhancing lesions spare callososeptal interface
+    - Reported in COVID-19 infection
+    - Beaded angiogram appearance
+- [Leukodystrophies](/document/leukodystrophies/f4ff3738-131c-46bf-be71-1811f2c1776c)
+    - Patterns vary by metabolic defect
+          - Metachromatic leukodystrophy, Alexander disease, X-linked adrenoleukodystrophy
+- ## Toxin-Induced Brain Injury
+  
+  
+    - Carbon monoxide or methanol poisoning
+    - Bilateral symmetric basal ganglia lesions
+          - Accompanying subcortical lesions in methanol poisoning
+
+# PATHOLOGY
+
+- ## General Features
+  
+  
+    - ### Etiology
+      
+      
+          - MS
+                  - Possibly viral-incited autoimmune reaction in genetically susceptible individuals
+                            - No "trigger" identified
+                  - Activated T cells attack myelinated axons
+                  - B cells, antibodies, macrophages, & microglia all contribute to lesions
+                  - Cox-2, iNOS may cause excitotoxic death of oligodendrocytes
+          - ADEM
+                  - Autoimmune-mediated demyelination
+                  - Characteristically arises subsequent to infection (viral respiratory) or vaccination
+          - NMOSD
+                  - Antibodies to aquaporin-4 (AQP-4) channels on astrocytic end feet
+                            - Technically not demyelinating
+                  - AQP-4 is dispersed throughout CNS
+                            - Highly expressed in optic nerves & spinal cord
+                  - AQP-4 antibodies are more highly expressed in peripheral blood than CSF
+          - Anti-MOG syndromes: Antibodies to MOG
+                  - MOG is CNS specific protein expressed on outer surface of myelin sheath
+          - Lyme disease
+                  - Caused by spirochete *Borrelia burgdorferi*
+                  - Tick-borne disease; deer tick (Ixodes scapularis) or Western black-legged tick (Ixodes pacificus)
+- ## Staging, Grading, & Classification
+  
+  
+    - Major clinical subtypes of MS
+          - Relapsing-remitting**** (85% initial presentation)
+          - Primary-progressive****, a.k.a. chronic progressive (5-10%)
+                  - Progressive from start
+          - Secondary-progressive****, a.k.a. relapsing progressive
+                  - By 10 years 50% & by 25 years 90% of relapsing-remitting patients enter secondary-progressive phase
+          - Progressive-relapsing****
+                  - Rare; defined as progressive disease with clear acute relapses ± full recovery
+                  - Periods between relapses are characterized by continuing disease progression
+          - Clinically isolated syndrome (CIS): Single episode > 24 hours; vast majority progress to MS after number of years
+    - MS variants/subtypes
+          - Malignant****: Younger patients, febrile prodrome, clinically fulminant, death in months
+          - Schilder ****type ("diffuse sclerosis"): Extensive, confluent, asymmetric demyelination in bilateral supra-/infratentorial parenchyma
+          - Baló ****type ("concentric sclerosis"): Large lesions with alternating zones of demyelinated/myelinated white matter
+- ## Gross Pathologic & Surgical Features
+  
+  
+    - Acute MS: Poorly delineated, yellowish-white, periventricular plaques
+    - Chronic MS: Gray, granular, well-demarcated plaques ± generalized volume loss
+- ## Microscopic Features
+  
+  
+    - MS
+          - Perivenous demyelination & oligodendrocyte loss
+                  - Active: Foamy macrophages with myelin fragments, lipids; reactive astrocytes + perivascular inflammation; some are hypercellular with atypical reactive astrocytes & mitoses (mimics tumor)
+                  - Chronic: Marked loss of myelin & oligodendrocytes; dense astrogliosis; minimal/no perivascular inflammation
+          - Axonal transection
+          - CSF positive for oligoclonal bands
+
+# CLINICAL ISSUES
+
+- ## Presentation
+  
+  
+    - ### Most common signs/symptoms
+      
+      
+          - MS
+                  - Variable
+                  - Initially impaired/double vision of acute ON (50% with positive MR develop MS)
+                  - Weakness, numbness, tingling, gait disturbances
+                  - ↓ sphincter control, blindness, paralysis, dementia
+                  - Cranial nerve palsies; usually multiple, 1-5% isolated (CNV & VI are most common)
+                  - Spinal cord symptoms in 80%
+          - ADEM
+                  - Cranial nerve palsies, encephalopathy, headache 2 days to 4 weeks after prodrome
+                  - Seizures in 10-35%
+                  - Monophasic illness
+                            - Can recur in small percentage of cases (controversial)
+          - NMO
+                  - Rapid onset of vision loss
+                  - Subsequent spinal cord symptoms, paralysis
+          - Lyme disease
+                  - Stereotypical expanding rash around tick bite: Erythema chronicum migrans
+                            - Infrequently recognized
+                  - Bell palsy, meningitis, arthralgias
+- ## Demographics
+  
+  
+    - Estimated 2,500,000 have MS worldwide
+          - MS most often occurs in temperate climates
+          - Most common disabling CNS disease of young adults: 1 in 1,000 in Western world
+    - 3-5% of MS is diagnosed before age 15 years
+    - 20% of childhood MS is initially diagnosed as ADEM
+    - 1/3 of acute demyelinating disease in children is anti-MOG
+- ## Natural History & Prognosis
+  
+  
+    - MS: 45% of MS patients are not severely affected & are nearly normal
+          - > 80% with "probable" MS & positive MR progress to clinically definite MS
+    - ADEM: Characteristically monophasic
+          - Recurrence suggests anti-MOG
+    - Anti-MOG syndromes are more frequently seen in young
+          - Encephalopathy is more common in younger patients, ON in older
+    - > 90% of NMOSD in pediatrics have relapsing disease
+    - Lyme disease: 11% develop neurologic manifestations
+- ## Treatment
+  
+  
+    - MS & NMOSD are both treated with immune-modulating therapy
+    - ADEM is typically treated with high-dose steroids
+          - Alternative treatments include IVIg & plasma exchange
+    - Anti-MOG syndromes respond quickly to steroid & IVIg treatment
+    - Lyme is treated with antibiotics
+          - No evidence that antibiotic therapy alters natural history
+
+# DIAGNOSTIC CHECKLIST
+
+- ## Image Interpretation Pearls
+  
+  
+    - 95% with definite MS clinically have positive MR
+
+ 12c5cb99-14a6-4793-9a7d-a6f1c3511f06
+
+## References
+
+# Selected References
+
+1. [Chhabda S et al: Relapsing demyelinating syndromes in children: a practical review of neuroradiological mimics. Front Neurol. 11:627, 2020](http://www.ncbi.nlm.nih.gov/pubmed/?term=32849169%5Bpmid%5D)
+1. [Padilha IG et al: Pediatric multiple sclerosis: from clinical basis to imaging spectrum and differential diagnosis. Pediatr Radiol. 50(6):776-92, 2020](http://www.ncbi.nlm.nih.gov/pubmed/?term=31925460%5Bpmid%5D)
+1. [Bulut E et al: Brain MRI findings in pediatric-onset neuromyelitis optica spectrum disorder: challenges in differentiation from acute disseminated encephalomyelitis. AJNR Am J Neuroradiol. 40(4):726-31, 2019](http://www.ncbi.nlm.nih.gov/pubmed/?term=30846436%5Bpmid%5D)
+1. [Galardi MM et al: Differential diagnosis of pediatric multiple sclerosis. Children (Basel). 6(6), 2019](http://www.ncbi.nlm.nih.gov/pubmed/?term=31163654%5Bpmid%5D)
+1. [Lana-Peixoto MA et al: Neuromyelitis optica spectrum disorder and anti-MOG syndromes. Biomedicines. 7(2), 2019](http://www.ncbi.nlm.nih.gov/pubmed/?term=31212763%5Bpmid%5D)
+1. [Troxell RM et al: Atypical pediatric demyelinating diseases of the central nervous system. Curr Neurol Neurosci Rep. 19(12):95, 2019](http://www.ncbi.nlm.nih.gov/pubmed/?term=31773416%5Bpmid%5D)
+1. [Reich DS et al: Multiple sclerosis. N Engl J Med. 378(2):169-80, 2018](http://www.ncbi.nlm.nih.gov/pubmed/?term=29320652%5Bpmid%5D)
+1. [Berzero G et al: Diagnosis and therapy of acute disseminated encephalomyelitis and its variants. Expert Rev Neurother. 16(1):83-101, 2016](http://www.ncbi.nlm.nih.gov/pubmed/?term=26620160%5Bpmid%5D)
+1. [Faguy K: Multiple sclerosis: an update. Radiol Technol. 87(5):529-50, 2016](http://www.ncbi.nlm.nih.gov/pubmed/?term=27146176%5Bpmid%5D)
+1. [Filippi M et al: MRI criteria for the diagnosis of multiple sclerosis: MAGNIMS consensus guidelines. Lancet Neurol. 15(3):292-303, 2016](http://www.ncbi.nlm.nih.gov/pubmed/?term=26822746%5Bpmid%5D)
+1. [Borchers AT et al: Lyme disease: a rigorous review of diagnostic criteria and treatment. J Autoimmun. 57:82-115, 2015](http://www.ncbi.nlm.nih.gov/pubmed/?term=25451629%5Bpmid%5D)
+1. [Koelman DL et al: Acute disseminated encephalomyelitis: current controversies in diagnosis and outcome. J Neurol. 262(9):2013-24, 2015](http://www.ncbi.nlm.nih.gov/pubmed/?term=25761377%5Bpmid%5D)
+1. [Wingerchuk DM et al: International consensus diagnostic criteria for neuromyelitis optica spectrum disorders. Neurology. 85(2):177-89, 2015](http://www.ncbi.nlm.nih.gov/pubmed/?term=26092914%5Bpmid%5D)
+1. [Flanagan EP et al: Neuromyelitis optica spectrum disorders. Curr Neurol Neurosci Rep. 14(9):483, 2014](http://www.ncbi.nlm.nih.gov/pubmed/?term=25027264%5Bpmid%5D)
+1. [Ketelslegers IA et al: A comparison of MRI criteria for diagnosing pediatric ADEM and MS. Neurology. 74(18):1412-5, 2010](http://www.ncbi.nlm.nih.gov/pubmed/?term=20335562%5Bpmid%5D)
+1. [VanLandingham M et al: An uncommon illness with a rare presentation: neurosurgical management of ADEM with tumefactive demyelination in children. Childs Nerv Syst. 26(5):655-61, 2010](http://www.ncbi.nlm.nih.gov/pubmed/?term=19949803%5Bpmid%5D)
+1. [Calabrese M et al: Cortical lesions in primary progressive multiple sclerosis: a 2-year longitudinal MR study. Neurology. 72(15):1330-6, 2009](http://www.ncbi.nlm.nih.gov/pubmed/?term=19365054%5Bpmid%5D)
+1. [Callen DJ et al: Role of MRI in the differentiation of ADEM from MS in children. Neurology. 72(11):968-73, 2009](http://www.ncbi.nlm.nih.gov/pubmed/?term=19038851%5Bpmid%5D)
+1. [Filippi M et al: Conventional MRI in multiple sclerosis. J Neuroimaging. 17 Suppl 1:3S-9S, 2007](http://www.ncbi.nlm.nih.gov/pubmed/?term=17425730%5Bpmid%5D)
+1. [Janardhan V et al: Multiple sclerosis: hyperintense lesions in the brain on nonenhanced T1-weighted MR images evidenced as areas of T1 shortening. Radiology. 244(3):823-31, 2007](http://www.ncbi.nlm.nih.gov/pubmed/?term=17690319%5Bpmid%5D)
+1. [Traboulsee AL et al: The role of MRI in the diagnosis of multiple sclerosis. Adv Neurol. 98:125-46, 2006](http://www.ncbi.nlm.nih.gov/pubmed/?term=16400831%5Bpmid%5D)
+1. [Polman CH et al: Diagnostic criteria for multiple sclerosis: 2005 revisions to the "McDonald Criteria". Ann Neurol. 58(6):840-6, 2005](http://www.ncbi.nlm.nih.gov/pubmed/?term=16283615%5Bpmid%5D)
+
+
+## Images
+
+
+### Selected Images
+
+![Sagittal T2 MR in a 9-year-old with optic neuritis shows multiple ill-defined hyperintensities in the medulla &amp; cervical cord. Subsequent serum testing revealed antibodies to aquaporin 4, confirming a diagnosis of neuromyelitis optica spectrum disorders (NMOSD).](images/app.statdx.com_image_thumbnail_9dd9f6f3-8e49-4e37-8adb-1a1245b14d28_annotated_true_size_900_quality_90_6a4e150f_20251018T152401Z.jpg)
+*Sagittal T2 MR in a 9-year-old with optic neuritis shows multiple ill-defined hyperintensities in the medulla &amp; cervical cord. Subsequent serum testing revealed antibodies to aquaporin 4, confirming a diagnosis of neuromyelitis optica spectrum disorders (NMOSD).*
+
+![Sagittal T2 MR in a 9-year-old with optic neuritis shows multiple ill-defined hyperintensities in the medulla &amp; cervical cord. Subsequent serum testing revealed antibodies to aquaporin 4, confirming a diagnosis of neuromyelitis optica spectrum disorders (NMOSD).](images/app.statdx.com_image_thumbnail_9dd9f6f3-8e49-4e37-8adb-1a1245b14d28_size_174_quality_85_a98eac63_20251018T152348Z.jpg)
+*Sagittal T2 MR in a 9-year-old with optic neuritis shows multiple ill-defined hyperintensities in the medulla &amp; cervical cord. Subsequent serum testing revealed antibodies to aquaporin 4, confirming a diagnosis of neuromyelitis optica spectrum disorders (NMOSD).*
+
+![Axial T1 C+ FS MR through the orbits shows diffuse bilateral optic nerve enhancement <img src='/img/arrows/WS.png'/> in this 9-year-old with vision loss. Clinical features were suggestive of NMOSD, but CSF analysis confirmed anti-myelin oligodendrocyte glycoprotein (MOG) disease.](images/app.statdx.com_image_thumbnail_0644d2a0-6cc0-4d76-aa55-0dc02b971f87_annotated_true_size_900_quality_90_b85e5c5c_20251018T152401Z.jpg)
+*Axial T1 C+ FS MR through the orbits shows diffuse bilateral optic nerve enhancement <img src='/img/arrows/WS.png'/> in this 9-year-old with vision loss. Clinical features were suggestive of NMOSD, but CSF analysis confirmed anti-myelin oligodendrocyte glycoprotein (MOG) disease.*
+
+![Axial NECT in a 16-year-old with progressive left-sided weakness after minor trauma shows a large, low-attenuation white matter lesion in the anterior right frontal lobe <img src='/img/arrows/WS.png'/> &amp; a smaller one near the right motor strip <img src='/img/arrows/WO.png'/>.](images/app.statdx.com_image_thumbnail_be1040b7-52b7-4198-85c6-7c794b869ca0_annotated_true_size_900_quality_90_40619fe9_20251018T152401Z.jpg)
+*Axial NECT in a 16-year-old with progressive left-sided weakness after minor trauma shows a large, low-attenuation white matter lesion in the anterior right frontal lobe <img src='/img/arrows/WS.png'/> &amp; a smaller one near the right motor strip <img src='/img/arrows/WO.png'/>.*
+
+![Sagittal T1 C+ MR in the same patient shows the borders of the large lesion nearest to the cortex to be nonenhancing <img src='/img/arrows/WS.png'/> as compared to the other margins <img src='/img/arrows/CS.png'/>. This open ring appearance can help distinguish tumefactive MS from abscess or neoplasm (which more typically have complete ring enhancement).](images/app.statdx.com_image_thumbnail_f6c3b95c-7708-493e-adf2-d530a89cf1b3_annotated_true_size_900_quality_90_9839b7e5_20251018T152401Z.jpg)
+*Sagittal T1 C+ MR in the same patient shows the borders of the large lesion nearest to the cortex to be nonenhancing <img src='/img/arrows/WS.png'/> as compared to the other margins <img src='/img/arrows/CS.png'/>. This open ring appearance can help distinguish tumefactive MS from abscess or neoplasm (which more typically have complete ring enhancement).*
+
+
+### Additional Images
+
+![Sagittal graphic illustrates MS plaques involving the corpus callosum, pons, &amp; spinal cord. Note the characteristic perpendicular orientation of the lesions <img src='/img/arrows/BS.png'/> at the callososeptal interface along penetrating venules.](images/app.statdx.com_image_thumbnail_5982d841-bf3c-48bf-981b-2b113c170f77_annotated_true_size_900_quality_90_2f597c2e_20251018T152401Z.jpg)
+*Sagittal graphic illustrates MS plaques involving the corpus callosum, pons, &amp; spinal cord. Note the characteristic perpendicular orientation of the lesions <img src='/img/arrows/BS.png'/> at the callososeptal interface along penetrating venules.*
+
+![Sagittal FLAIR MR shows numerous MS plaques with typical perpendicular orientation at the callososeptal interface along penetrating venules (&quot;Dawson fingers&quot;) as well as in the subcortical white matter.](images/app.statdx.com_image_thumbnail_61781d1c-c076-4c21-b20e-880cfd4f55d0_annotated_true_size_900_quality_90_db0af7fe_20251018T152401Z.jpg)
+*Sagittal FLAIR MR shows numerous MS plaques with typical perpendicular orientation at the callososeptal interface along penetrating venules (&quot;Dawson fingers&quot;) as well as in the subcortical white matter.*
+
+![Sagittal FLAIR MR shows perpendicular callosal/pericallosal MS plaques with hyperintense rims &amp; hypointense centers (with corresponding hypointensities also demonstrated on T1 as &quot;black holes,&quot; not shown). Note an additional posterior fossa lesion <img src='/img/arrows/WS.png'/>.](images/app.statdx.com_image_thumbnail_401faf53-5b53-457b-a4cf-e082df97355b_annotated_true_size_900_quality_90_5f2d28b5_20251018T152401Z.jpg)
+*Sagittal FLAIR MR shows perpendicular callosal/pericallosal MS plaques with hyperintense rims &amp; hypointense centers (with corresponding hypointensities also demonstrated on T1 as &quot;black holes,&quot; not shown). Note an additional posterior fossa lesion <img src='/img/arrows/WS.png'/>.*
+
+![Axial T1 C+ MR demonstrates multiple nodular, enhancing multiple sclerosis plaques <img src='/img/arrows/CS.png'/>. Note the common periventricular location with perpendicular orientation as well as the involvement of subcortical white matter.](images/app.statdx.com_image_thumbnail_189e1205-c396-4b72-b951-2dbe76e9e36e_annotated_true_size_900_quality_90_c8c44a6e_20251018T152401Z.jpg)
+*Axial T1 C+ MR demonstrates multiple nodular, enhancing multiple sclerosis plaques <img src='/img/arrows/CS.png'/>. Note the common periventricular location with perpendicular orientation as well as the involvement of subcortical white matter.*
+
+![Axial FLAIR MR shows confluent multiple sclerosis plaques in commonly seen periventricular locations.](35652553-b36f-4763-b184-1ab3ab11db8d)
+*Axial FLAIR MR shows confluent multiple sclerosis plaques in commonly seen periventricular locations.*
+
+![Axial FLAIR MR in a 9-year-old patient with altered mental status &amp; hyperreflexia shows ill-defined, hyperintense lesions in the thalami <img src='/img/arrows/WC.png'/>, basal ganglia <img src='/img/arrows/WS.png'/>, &amp; insula <img src='/img/arrows/CS.png'/>. Involvement of the deep nuclei is a relatively common feature of acute disseminated encephalomyelitis.](0e99452e-0b58-4f4c-bfac-641ed551772f)
+*Axial FLAIR MR in a 9-year-old patient with altered mental status &amp; hyperreflexia shows ill-defined, hyperintense lesions in the thalami <img src='/img/arrows/WC.png'/>, basal ganglia <img src='/img/arrows/WS.png'/>, &amp; insula <img src='/img/arrows/CS.png'/>. Involvement of the deep nuclei is a relatively common feature of acute disseminated encephalomyelitis.*
+
+![Axial FLAIR MR shows large lesions in the thalamus &amp; basal ganglia <img src='/img/arrows/WS.png'/> in this 16-year-old with a headache &amp; weakness 2 weeks after a viral illness. Acute disseminated encephalomyelitis will frequently affect deep gray matter structures.](33c4db71-7819-4951-82d5-6179d57c46ca)
+*Axial FLAIR MR shows large lesions in the thalamus &amp; basal ganglia <img src='/img/arrows/WS.png'/> in this 16-year-old with a headache &amp; weakness 2 weeks after a viral illness. Acute disseminated encephalomyelitis will frequently affect deep gray matter structures.*
+
+![Coronal FLAIR MR in a 12-year-old patient with neuromyelitis optica &amp; bladder dysfunction shows large lesions extending across the corpus callosum <img src='/img/arrows/CS.png'/> &amp; left cerebral peduncle <img src='/img/arrows/WS.png'/>.](ef83ab0b-2e3d-42bf-93c7-bca7c44ab4a8)
+*Coronal FLAIR MR in a 12-year-old patient with neuromyelitis optica &amp; bladder dysfunction shows large lesions extending across the corpus callosum <img src='/img/arrows/CS.png'/> &amp; left cerebral peduncle <img src='/img/arrows/WS.png'/>.*
+
+![Axial NECT in a 14-year-old patient with vomiting shows a nonspecific, low-attenuation lesion <img src='/img/arrows/WO.png'/> in the left posterior frontal subcortical white matter.](df4278d1-a558-4b35-8d57-4eb498198844)
+*Axial NECT in a 14-year-old patient with vomiting shows a nonspecific, low-attenuation lesion <img src='/img/arrows/WO.png'/> in the left posterior frontal subcortical white matter.*
+
+![Axial FLAIR MR in the same patient acquired the next day shows several ovoid MS plaques <img src='/img/arrows/WS.png'/>. Active lesions will also show contrast enhancement &amp; restricted diffusion.](98da69ab-68a3-4e4e-a449-cc1d3d5b039c)
+*Axial FLAIR MR in the same patient acquired the next day shows several ovoid MS plaques <img src='/img/arrows/WS.png'/>. Active lesions will also show contrast enhancement &amp; restricted diffusion.*
+
+![Axial FLAIR MR in a 14-year-old with MS shows multiple ovoid lesions oriented perpendicular to the long axis of the lateral ventricles <img src='/img/arrows/WS.png'/>  with hazy ↑ signal intensity in the white matter between them.](535bc8f9-9d5a-4a71-ace3-2096aed4a3bb)
+*Axial FLAIR MR in a 14-year-old with MS shows multiple ovoid lesions oriented perpendicular to the long axis of the lateral ventricles <img src='/img/arrows/WS.png'/>  with hazy ↑ signal intensity in the white matter between them.*
+
+![Axial T2 MR in a 17-year-old with Bal&oacute; concentric sclerosis <img src='/img/arrows/CS.png'/>.](1917d677-6c61-4ff0-9e4b-e361b7735747)
+*Axial T2 MR in a 17-year-old with Bal&oacute; concentric sclerosis <img src='/img/arrows/CS.png'/>.*
+
+![Sagittal T1 C+ FS MR shows an enhancing MS lesion in the dorsal aspect of the cervical cord <img src='/img/arrows/WC.png'/>. Approximately 2/3 of spinal cord MS lesions are found in the cervical cord. Typical features include a dorsal intramedullary lesion spanning &lt; 2 vertebral segments in length.](ea063d1c-a56a-4f8d-b816-59c489f886d3)
+*Sagittal T1 C+ FS MR shows an enhancing MS lesion in the dorsal aspect of the cervical cord <img src='/img/arrows/WC.png'/>. Approximately 2/3 of spinal cord MS lesions are found in the cervical cord. Typical features include a dorsal intramedullary lesion spanning &lt; 2 vertebral segments in length.*
+
+![Axial FLAIR MR shows numerous peripheral white matter &amp; cortical lesions that exhibited robust contrast enhancement (not shown) in an 18-year-old woman with malignant (Marburg) MS. The patient presented with a 2-week history of behavioral changes &amp; leg pain &amp; died 3 weeks after presentation. The autopsy showed typical demyelinating pathology.](6037cba2-b41b-4f70-924c-eff9b9fa2adb)
+*Axial FLAIR MR shows numerous peripheral white matter &amp; cortical lesions that exhibited robust contrast enhancement (not shown) in an 18-year-old woman with malignant (Marburg) MS. The patient presented with a 2-week history of behavioral changes &amp; leg pain &amp; died 3 weeks after presentation. The autopsy showed typical demyelinating pathology.*
+
+![Axial T1 C+ FS MR in a patient with MS shows ring-enhancing masses of active demyelination. The rings of enhancement are incomplete with each ring defect pointing towards an adjacent cortex.](8bd36d87-e22a-4ecd-9c56-0c05b7d8b5e9)
+*Axial T1 C+ FS MR in a patient with MS shows ring-enhancing masses of active demyelination. The rings of enhancement are incomplete with each ring defect pointing towards an adjacent cortex.*
+
+![Coronal T1 C+ MR shows a superficial hypointense mass in the left parasagittal posterior frontal region with a peripheral crescent of incomplete or &quot;horseshoe&quot; enhancement <img src='/img/arrows/WS.png'/>. This enhancement pattern is classic for tumefactive demyelinating disease, most commonly MS.](c0b8632c-e2e4-4a9b-8000-4d891f580d12)
+*Coronal T1 C+ MR shows a superficial hypointense mass in the left parasagittal posterior frontal region with a peripheral crescent of incomplete or &quot;horseshoe&quot; enhancement <img src='/img/arrows/WS.png'/>. This enhancement pattern is classic for tumefactive demyelinating disease, most commonly MS.*
+
+![Axial FLAIR MR shows a case of proven tumefactive MS  <img src='/img/arrows/BC.png'/> with extensive surrounding white matter edema <img src='/img/arrows/WS.png'/>. Note that the imaging features present in this case could also be seen with neoplasm.](29decf6b-f0d7-43f9-a4bf-788ed632fd56)
+*Axial FLAIR MR shows a case of proven tumefactive MS  <img src='/img/arrows/BC.png'/> with extensive surrounding white matter edema <img src='/img/arrows/WS.png'/>. Note that the imaging features present in this case could also be seen with neoplasm.*
+
+![Long TE MRS in a case of tumefactive MS  reveals elevated choline <img src='/img/arrows/WS.png'/>, ↓ NAA <img src='/img/arrows/WO.png'/>, &amp; a lactate doublet <img src='/img/arrows/WC.png'/>. These MRS findings could be consistent with acute demyelination &amp; probably reflect a combination of membrane disruption, neuronal loss or dysfunction, &amp; inflammation. Note that the MRS findings in MS are not specific. The spectral pattern of demyelination &amp; low-grade neoplasms can be similar &amp; should therefore be interpreted cautiously.](c16341cd-e0de-42ba-943c-f51e0344ca54)
+*Long TE MRS in a case of tumefactive MS  reveals elevated choline <img src='/img/arrows/WS.png'/>, ↓ NAA <img src='/img/arrows/WO.png'/>, &amp; a lactate doublet <img src='/img/arrows/WC.png'/>. These MRS findings could be consistent with acute demyelination &amp; probably reflect a combination of membrane disruption, neuronal loss or dysfunction, &amp; inflammation. Note that the MRS findings in MS are not specific. The spectral pattern of demyelination &amp; low-grade neoplasms can be similar &amp; should therefore be interpreted cautiously.*
+
+![Axial T1 C+ MR shows numerous enhancing MS plaques that were present throughout the infratentorial &amp; supratentorial brain. MS lesions may show homogeneous enhancement but may also exhibit ring or incomplete ring patterns of enhancement.](9818c56a-8f4e-4e75-8d5e-86a6bdb62f40)
+*Axial T1 C+ MR shows numerous enhancing MS plaques that were present throughout the infratentorial &amp; supratentorial brain. MS lesions may show homogeneous enhancement but may also exhibit ring or incomplete ring patterns of enhancement.*
+

docs_md/articles/extraventricular-obstructive-hydrocephalus_a0886d4c-f504-4165-bb52-2400e2385f68.md

@@ -0,0 +1,301 @@
+---
+title: "Extraventricular Obstructive Hydrocephalus"
+docid: "a0886d4c-f504-4165-bb52-2400e2385f68"
+authors:
+  - key: "a25c450b-3d34-4f64-bba3-cc0834813df6"
+    value: "Miral D. Jhaveri, MD, MBA"
+breadcrumbs:
+  -
+    name: "Brain"
+    slug: "brain"
+    treeNodeId: "6d8829f1-14d7-45af-8675-255189aa526a"
+  -
+    name: "Diagnosis"
+    slug: "diagnosis"
+    treeNodeId: "51c00394-446e-4a38-94af-d3b1d14d34e8"
+  -
+    name: "Anatomy-Based Diagnoses"
+    slug: "anatomy-based-diagnoses"
+    treeNodeId: "529d3e33-f508-498c-bc70-cf962e81e629"
+  -
+    name: "Ventricles and Cisterns"
+    slug: "ventricles-and-cisterns"
+    treeNodeId: "33b267f0-908c-4c77-81f8-f6135d1bc592"
+  -
+    name: "Hydrocephalus"
+    slug: "hydrocephalus"
+    treeNodeId: "9ce86e3b-fab6-4657-9e51-5f47bb1a51b5"
+  -
+    name: "Extraventricular Obstructive Hydrocephalus"
+    slug: "extraventricular-obstructive-hydro-"
+    treeNodeId: null
+category: "Brain"
+documentVersionId: "244d0107-0a80-48b5-96b6-e095c226c02a"
+imageCount: 9
+lastUpdated: "08/20/20"
+pageDescription: "Extraventricular Obstructive Hydrocephalus"
+pageKeywords: "Brain, Diagnosis, Anatomy-Based Diagnoses, Ventricles and Cisterns, Hydrocephalus, Extraventricular Obstructive Hydrocephalus"
+pageTitle: "Extraventricular Obstructive Hydrocephalus | STATdx"
+enhancedTitle: "Extraventricular Obstructive Hydrocephalus"
+type: "DX"
+references: true
+breadcrumbs:
+  - "Brain"
+  - "Diagnosis"
+  - "Anatomy-Based Diagnoses"
+  - "Ventricles and Cisterns"
+  - "Hydrocephalus"
+  - "Extraventricular Obstructive Hydrocephalus"
+---
+# KEY FACTS
+
+- ## Terminology
+  
+  
+    - Extraventricular obstructive hydrocephalus (EVOH): Enlarged ventricles due to obstruction located outside ventricular system
+    - Synonym: "Communicating" hydrocephalus
+- ## Imaging
+  
+  
+    - Impaired absorption of CSF distal to 4th ventricle outlet foramina
+    - Ventricular size varies with duration of obstruction
+    - All ventricles enlarged with no intraventricular obstructive cause
+    - Lateral, 3rd, and 4th ventricles dilated
+    - ± periventricular white matter interstitial edema
+    - ± abnormal density/intensity of cisternal CSF ± leptomeningeal enhancement
+- ## Top Differential Diagnoses
+  
+  
+    - Intraventricular obstructive hydrocephalus
+    - Ventricular enlargement 2° to parenchymal loss
+    - Normal-pressure hydrocephalus
+- ## Pathology
+  
+  
+    - Hemorrhage → fibrosis/obstruction of subarachnoid space
+          - Most common cause of EVOH
+    - Other etiologies include suppurative meningitis, neoplastic or inflammatory exudates
+    - Subarachnoid hemorrhage (SAH), exudates may fibrose/occlude subarachnoid space, reduce CSF pulsations
+- ## Clinical Issues
+  
+  
+    - Headache, papilledema
+    - Nausea, vomiting, diplopia (cranial nerve palsy)
+- ## Diagnostic Checklist
+  
+  
+    - EVOH: Generalized ventricular enlargement with abnormal density/intensity in basal cisterns ± leptomeningeal enhancement
+
+# TERMINOLOGY
+
+- ## Abbreviations
+  
+  
+    - Extraventricular obstructive hydrocephalus (EVOH)
+- ## Synonyms
+  
+  
+    - "Communicating" hydrocephalus
+- ## Definitions
+  
+  
+    - Enlarged ventricles due to obstruction located outside ventricular system
+
+# IMAGING
+
+- ## General Features
+  
+  
+    - ### Best diagnostic clue
+      
+      
+          - Lateral, 3rd, and 4th ventricles all dilated
+          - ± abnormal density/intensity of cisternal CSF ± leptomeningeal enhancement
+    - ### Location
+      
+      
+          - Obstruction distal to 4th ventricle outlet foramina
+    - ### Size
+      
+      
+          - Bifrontal horn to intracranial diameter ratio > 0.3
+          - Temporal horn width > 3 mm
+    - ### Morphology
+      
+      
+          - All ventricles enlarged
+                  - Generally proportionate, symmetrical increase
+                  - No intraventricular obstructive cause
+- ## CT Findings
+  
+  
+    - ### NECT
+      
+      
+          - Variable ventricular dilatation ± basal cisterns effaced
+          - If subarachnoid hemorrhage (SAH), look for hyperdense CSF
+    - ### CECT
+      
+      
+          - Look for sulcal/cisternal enhancement
+- ## MR Findings
+  
+  
+    - ### T1WI
+      
+      
+          - "Dirty" CSF, ventricular dilatation
+    - ### T2WI
+      
+      
+          - Dilated ventricles ± periventricular white matter interstitial edema
+          - Effacement of cortical sulci
+          - Hypointense CSF-SAH, exudates
+    - ### FLAIR
+      
+      
+          - ± periventricular white matter interstitial edema better delineated than T2
+    - ### T1WI C+
+      
+      
+          - ± enhancement of basal cisterns/sulci
+                  - Meningitis, carcinomatosis, etc.
+    - 3D CISS/FIESTA
+          - Exquisitely delineates CSF spaces and helps to exclude intraventricular obstruction
+- ## Imaging Recommendations
+  
+  
+    - ### Best imaging tool
+      
+      
+          - MR with T1WI C+
+          - 3D CISS/FIESTA
+- ## Other Modality Findings
+  
+  
+    - Isotope cisternography may show ventricular reflux, stasis (EVOH)
+
+# DIFFERENTIAL DIAGNOSIS
+
+- ## Intraventricular Obstructive Hydrocephalus
+  
+  
+    - Global/focal enlarged ventricles due to obstruction proximal to 4th ventricle outflow
+- ## Ventricular Enlargement Secondary to Parenchymal Loss
+  
+  
+    - Neurodegenerative disease, cerebritis, hypoxia/ischemia
+    - Diffuse/focal enlargement of sulci, cisterns
+- [Normal-Pressure Hydrocephalus](/document/normal-pressure-hydrocephalus/ba3f857d-58de-4f21-8463-1631b4cb9972)
+    - Ventricular enlargement with normal CSF pressure
+    - Sulci normal/minimally enlarged
+    - Progressive dementia, gait disturbance, incontinence
+
+# PATHOLOGY
+
+- ## General Features
+  
+  
+    - ### Etiology
+      
+      
+          - Obstruction to CSF flow at level of basal cisterns or arachnoid villi
+                  - Also reduced CSF pulsations reduce venous resorption of CSF
+          - SAH: Most common cause of EVOH
+          - Other etiologies include suppurative meningitis, neoplastic inflammatory exudates
+                  - All lead to subarachnoid scarring, reduced CSF pulsations
+- ## Gross Pathologic & Surgical Features
+  
+  
+    - Generalized ventricular dilatation
+    - SAH, exudates in basal cisterns & convexity sulci
+    - Meningeal fibrosis, arachnoid adhesions
+
+# CLINICAL ISSUES
+
+- ## Presentation
+  
+  
+    - ### Most common signs/symptoms
+      
+      
+          - Headache, papilledema
+          - Nausea, vomiting, diplopia (cranial nerve palsy)
+- ## Natural History & Prognosis
+  
+  
+    - Usually progressive unless shunted and primary cause treated
+- ## Treatment
+  
+  
+    - CSF diversion (shunt); directed to primary cause
+
+# DIAGNOSTIC CHECKLIST
+
+- ## Consider
+  
+  
+    - EVOH: Generalized ventricular enlargement with abnormal density/intensity in basal cisterns ± leptomeningeal enhancement
+
+ 94b03593-3810-49dd-a698-ad9f46f7ba1f
+
+## References
+
+# Selected References
+
+1. [Capone PM et al: Neuroimaging of normal pressure hydrocephalus and hydrocephalus. Neurol Clin. 38(1):171-83, 2020](http://www.ncbi.nlm.nih.gov/pubmed/?term=31761057%5Bpmid%5D)
+1. [Farb R et al: Hydrocephalus and CSF disorders. Diseases of the brain, head and neck, spine 2020-3: Diagnostic Imaging. Cham (CH): Springer; 11-24, 2020](http://www.ncbi.nlm.nih.gov/pubmed/?term=32119247%5Bpmid%5D)
+1. [Fowler JB et al: Ventriculoperitoneal shunt. Treasure Island (FL): StatPearls Publishing, 2020](http://www.ncbi.nlm.nih.gov/pubmed/?term=29083724%5Bpmid%5D)
+1. [Roth J et al: The added value of magnetic resonance imaging cisternography and ventriculography as a diagnostic aid in pediatric Hydrocephalus. Pediatr Neurosurg. 54(3):165-72, 2019](http://www.ncbi.nlm.nih.gov/pubmed/?term=30870836%5Bpmid%5D)
+1. [Fink KR et al: Imaging of nontraumatic neuroradiology emergencies. Radiol Clin North Am. 53(4):871-90, 2015](http://www.ncbi.nlm.nih.gov/pubmed/?term=26046515%5Bpmid%5D)
+1. [Flannery AM et al: Pediatric hydrocephalus: systematic literature review and evidence-based guidelines. Part 1: introduction and methodology. J Neurosurg Pediatr. 14 Suppl 1:3-7, 2014](http://www.ncbi.nlm.nih.gov/pubmed/?term=25988777%5Bpmid%5D)
+1. [Grunwald IQ et al: Aneurysmal SAH: current management and complications associated with treatment and disease. J Invasive Cardiol. 26(1):30-7, 2014](http://www.ncbi.nlm.nih.gov/pubmed/?term=24402809%5Bpmid%5D)
+1. [Krähenbühl AK et al: Endoscopic temporal ventriculocisternostomy: an option for the treatment of trapped temporal horns. J Neurosurg Pediatr. 11(5):568-74, 2013](http://www.ncbi.nlm.nih.gov/pubmed/?term=23521153%5Bpmid%5D)
+1. [McAllister JP 2nd: Pathophysiology of congenital and neonatal hydrocephalus. Semin Fetal Neonatal Med. 17(5):285-94, 2012](http://www.ncbi.nlm.nih.gov/pubmed/?term=22800608%5Bpmid%5D)
+1. [Feng F et al: Evaluation of radionuclide cerebrospinal fluid scintigraphy as a guide in the management of patients with hydrocephalus. Clin Imaging. 33(2):85-9, 2009](http://www.ncbi.nlm.nih.gov/pubmed/?term=19237049%5Bpmid%5D)
+1. [Yamada S et al: Visualization of cerebrospinal fluid movement with spin labeling at MR imaging: preliminary results in normal and pathophysiologic conditions. Radiology. 249(2):644-52, 2008](http://www.ncbi.nlm.nih.gov/pubmed/?term=18936318%5Bpmid%5D)
+1. [Greitz D: Paradigm shift in hydrocephalus research in legacy of Dandy's pioneering work: rationale for third ventriculostomy in communicating hydrocephalus. Childs Nerv Syst. 23(5):487-9, 2007](http://www.ncbi.nlm.nih.gov/pubmed/?term=-1%5Bpmid%5D)
+1. [ter Laan M et al: Improvement after treatment of hydrocephalus in aneurysmal subarachnoid haemorrhage: implications for grading and prognosis. Acta Neurochir (Wien). 148(3):325-8; discussion 328, 2006](http://www.ncbi.nlm.nih.gov/pubmed/?term=16328775%5Bpmid%5D)
+1. [Greitz D: Radiological assessment of hydrocephalus: new theories and implications for therapy. Neurosurg Rev. 27(3):145-65; discussion 166-7, 2004](http://www.ncbi.nlm.nih.gov/pubmed/?term=15164255%5Bpmid%5D)
+1. [Kehler U et al: Extraventricular intracisternal obstructive hydrocephalus--a hypothesis to explain successful 3rd ventriculostomy in communicating hydrocephalus. Pediatr Neurosurg. 38(2):98-101, 2003](http://www.ncbi.nlm.nih.gov/pubmed/?term=12566844%5Bpmid%5D)
+1. [Biedert S et al: [Extraventricular obstructive hydrocephalus.] Fortschr Neurol Psychiatr. 62(11):405-8, 1994](http://www.ncbi.nlm.nih.gov/pubmed/?term=7829027%5Bpmid%5D)
+
+
+## Images
+
+
+### Selected Images
+
+![Axial NECT shows acute subarachnoid hemorrhage <img src='/img/arrows/CC.png'/> in the basal cisterns and early extraventricular obstructive hydrocephalus with dilatation of all the ventricles and subtle periventricular hypodensity <img src='/img/arrows/CO.png'/> due to interstitial edema.](images/app.statdx.com_image_thumbnail_5111b0b3-10b0-4451-b80f-787287add3e4_annotated_true_size_900_quality_90_52e5b3da_20251018T164521Z.jpg)
+*Axial NECT shows acute subarachnoid hemorrhage <img src='/img/arrows/CC.png'/> in the basal cisterns and early extraventricular obstructive hydrocephalus with dilatation of all the ventricles and subtle periventricular hypodensity <img src='/img/arrows/CO.png'/> due to interstitial edema.*
+
+![Axial NECT shows acute subarachnoid hemorrhage <img src='/img/arrows/CC.png'/> in the basal cisterns and early extraventricular obstructive hydrocephalus with dilatation of all the ventricles and subtle periventricular hypodensity <img src='/img/arrows/CO.png'/> due to interstitial edema.](images/app.statdx.com_image_thumbnail_5111b0b3-10b0-4451-b80f-787287add3e4_size_174_quality_85_07f2e641_20251018T155131Z.jpg)
+*Axial NECT shows acute subarachnoid hemorrhage <img src='/img/arrows/CC.png'/> in the basal cisterns and early extraventricular obstructive hydrocephalus with dilatation of all the ventricles and subtle periventricular hypodensity <img src='/img/arrows/CO.png'/> due to interstitial edema.*
+
+![Axial FLAIR MR images (top) in a patient with breast carcinoma leptomeningeal metastasis shows dilatation of the ventricles  <img src='/img/arrows/CS.png'/>  with mild periventricular interstitial edema <img src='/img/arrows/CO.png'/>. Axial T1 C+ MR (bottom) shows extensive leptomeningeal enhancement <img src='/img/arrows/CC.png'/> along the cerebellar folia.](images/app.statdx.com_image_thumbnail_d998cd4d-9969-40a5-af8f-4530c1fa1cf0_annotated_true_size_900_quality_90_19eb7d4c_20251018T164521Z.jpg)
+*Axial FLAIR MR images (top) in a patient with breast carcinoma leptomeningeal metastasis shows dilatation of the ventricles  <img src='/img/arrows/CS.png'/>  with mild periventricular interstitial edema <img src='/img/arrows/CO.png'/>. Axial T1 C+ MR (bottom) shows extensive leptomeningeal enhancement <img src='/img/arrows/CC.png'/> along the cerebellar folia.*
+
+![Axial T2 MR in a 21-year-old patient with a remote history of meningitis shows chronic &quot;compensated&quot; extraventricular communicating hydrocephalus with marked dilatation of the lateral <img src='/img/arrows/CC.png'/> and 3rd ventricles <img src='/img/arrows/CS.png'/>.](images/app.statdx.com_image_thumbnail_99b1acc6-b089-48c5-bc97-c72d4bd09eb0_annotated_true_size_900_quality_90_dc39d287_20251018T164521Z.jpg)
+*Axial T2 MR in a 21-year-old patient with a remote history of meningitis shows chronic &quot;compensated&quot; extraventricular communicating hydrocephalus with marked dilatation of the lateral <img src='/img/arrows/CC.png'/> and 3rd ventricles <img src='/img/arrows/CS.png'/>.*
+
+![Sagittal T1 MR in the same patient shows a patent widened cerebral aqueduct <img src='/img/arrows/CC.png'/> and foramen of Magendie <img src='/img/arrows/CS.png'/> with dilatation of the 4th ventricle <img src='/img/arrows/CO.png'/>. In longstanding &quot;compensated&quot; hydrocephalus, there is no periventricular interstitial edema around the ventricles, as in this case.](images/app.statdx.com_image_thumbnail_92b29be1-65a5-4179-9175-265ac3a16e7b_annotated_true_size_900_quality_90_3b9fecbf_20251018T164521Z.jpg)
+*Sagittal T1 MR in the same patient shows a patent widened cerebral aqueduct <img src='/img/arrows/CC.png'/> and foramen of Magendie <img src='/img/arrows/CS.png'/> with dilatation of the 4th ventricle <img src='/img/arrows/CO.png'/>. In longstanding &quot;compensated&quot; hydrocephalus, there is no periventricular interstitial edema around the ventricles, as in this case.*
+
+
+### Additional Images
+
+![Axial T1WI C+ MR demonstrates subtle leptomeningeal enhancement in the left sylvian fissure <img src='/img/arrows/CO.png'/> in this patient with tuberculous meningitis. There is mild dilatation of the lateral ventricles <img src='/img/arrows/CS.png'/> due to extraventricular obstructive hydrocephalus.](images/app.statdx.com_image_thumbnail_2a43dda8-e5ae-43ec-94c6-0f57c803a451_annotated_true_size_900_quality_90_1b106673_20251018T164521Z.jpg)
+*Axial T1WI C+ MR demonstrates subtle leptomeningeal enhancement in the left sylvian fissure <img src='/img/arrows/CO.png'/> in this patient with tuberculous meningitis. There is mild dilatation of the lateral ventricles <img src='/img/arrows/CS.png'/> due to extraventricular obstructive hydrocephalus.*
+
+![Coronal T1WI MR in a toddler with rapid head growth for 4 months shows enlarged ventricular trigone on the left and enlarging subarachnoid spaces at an age when they should be shrinking. MR venography showed occlusion of both transverse sinuses.](images/app.statdx.com_image_thumbnail_ebff970c-aa3e-4179-bbd9-c97acd72f056_annotated_true_size_900_quality_90_c2d1d8f1_20251018T164521Z.jpg)
+*Coronal T1WI MR in a toddler with rapid head growth for 4 months shows enlarged ventricular trigone on the left and enlarging subarachnoid spaces at an age when they should be shrinking. MR venography showed occlusion of both transverse sinuses.*
+
+![Axial NECT shows hyperdense material in the basal cisterns <img src='/img/arrows/BS.png'/> and sylvian fissures <img src='/img/arrows/BO.png'/> in acute subarachnoid hemorrhage. There is early dilatation of the ventricles <img src='/img/arrows/CO.png'/> with mild periventricular edema <img src='/img/arrows/CS.png'/> due to interstitial edema.](images/app.statdx.com_image_thumbnail_8ec2b8fa-6b76-4d89-b2ab-6f1f7e0a4d3c_annotated_true_size_900_quality_90_9e79e2bf_20251018T164521Z.jpg)
+*Axial NECT shows hyperdense material in the basal cisterns <img src='/img/arrows/BS.png'/> and sylvian fissures <img src='/img/arrows/BO.png'/> in acute subarachnoid hemorrhage. There is early dilatation of the ventricles <img src='/img/arrows/CO.png'/> with mild periventricular edema <img src='/img/arrows/CS.png'/> due to interstitial edema.*
+
+![Axial NECT shows acute subarachnoid hemorrhage in the basal cisterns <img src='/img/arrows/CC.png'/> and sylvian fissures <img src='/img/arrows/CS.png'/>. There is early extraventricular obstructive hydrocephalus with mild periventricular hypodensity <img src='/img/arrows/CO.png'/> due to interstitial edema.](images/app.statdx.com_image_thumbnail_da3cea4c-f283-4f12-b661-5b1c2df2b201_annotated_true_size_900_quality_90_8c48b911_20251018T164521Z.jpg)
+*Axial NECT shows acute subarachnoid hemorrhage in the basal cisterns <img src='/img/arrows/CC.png'/> and sylvian fissures <img src='/img/arrows/CS.png'/>. There is early extraventricular obstructive hydrocephalus with mild periventricular hypodensity <img src='/img/arrows/CO.png'/> due to interstitial edema.*
+
+![Axial T1WI C+ MR shows extensive leptomeningeal enhancement of the basal cisterns in neurosarcoidosis <img src='/img/arrows/CS.png'/>. Notice the early communicating hydrocephalus with the dilated 3rd ventricle <img src='/img/arrows/CC.png'/> and temporal horns <img src='/img/arrows/CO.png'/>.](f314f067-37d3-4bfe-b551-1dd1cd36f1e3)
+*Axial T1WI C+ MR shows extensive leptomeningeal enhancement of the basal cisterns in neurosarcoidosis <img src='/img/arrows/CS.png'/>. Notice the early communicating hydrocephalus with the dilated 3rd ventricle <img src='/img/arrows/CC.png'/> and temporal horns <img src='/img/arrows/CO.png'/>.*
+

docs_md/articles/hydrocephalus_e9481739-278e-4682-ab1e-4326a77c3d0c.md

@@ -0,0 +1,480 @@
+---
+title: "Hydrocephalus"
+docid: "e9481739-278e-4682-ab1e-4326a77c3d0c"
+authors:
+  - key: "838e1722-2479-4fbd-a5fe-d965980a1a2c"
+    value: "Blaise V. Jones, MD"
+breadcrumbs:
+  -
+    name: "Pediatrics"
+    slug: "pediatrics"
+    treeNodeId: "a915965c-d436-44cf-ae65-2f22e7246ea4"
+  -
+    name: "Diagnosis"
+    slug: "diagnosis"
+    treeNodeId: "2b5cea64-a083-489e-ac0c-ec14ba059026"
+  -
+    name: "Pediatric Neuroradiology"
+    slug: "pediatric-neuroradiology"
+    treeNodeId: "d0eb8f4a-e769-43dd-896c-8c9c27ce8759"
+  -
+    name: "Brain"
+    slug: "brain"
+    treeNodeId: "feaaadba-649b-4f0a-9aad-9188a8f9926a"
+  -
+    name: "Anatomy-Based Diagnoses"
+    slug: "anatomy-based-diagnoses"
+    treeNodeId: "0c0853dc-8217-425b-86d1-2d958e17f1f9"
+  -
+    name: "Ventricles and Cisterns"
+    slug: "ventricles-and-cisterns"
+    treeNodeId: "8b535c75-9cd3-445e-a4c7-345b2e444f03"
+  -
+    name: "Hydrocephalus"
+    slug: "hydrocephalus"
+    treeNodeId: null
+category: "Pediatrics"
+cmeTopicId: "bddbd7cd-39c8-4b51-98d3-3e314108c4d1"
+documentVersionId: "47d2ee1e-6049-4ddc-8280-fc06e5d281da"
+imageCount: 25
+lastUpdated: "02/06/24"
+pageDescription: "Hydrocephalus"
+pageKeywords: "Pediatrics, Diagnosis, Pediatric Neuroradiology, Brain, Anatomy-Based Diagnoses, Ventricles and Cisterns, Hydrocephalus"
+pageTitle: "Hydrocephalus | STATdx"
+enhancedTitle: "Hydrocephalus"
+type: "DX"
+references: true
+breadcrumbs:
+  - "Pediatrics"
+  - "Diagnosis"
+  - "Pediatric Neuroradiology"
+  - "Brain"
+  - "Anatomy-Based Diagnoses"
+  - "Ventricles and Cisterns"
+  - "Hydrocephalus"
+---
+# KEY FACTS
+
+- ## Terminology
+  
+  
+    - Ventriculomegaly caused by
+          - Obstruction of CSF egress from ventricles: Intraventricular obstructive hydrocephalus
+          - Decreased CSF resorption from subarachnoid space: Extraventricular obstructive hydrocephalus
+          - Increased CSF production
+    - Use FOHR to track ventricle size over time
+          - (Transverse diameter of frontal horns + transverse diameter of occipital horns) ÷ 2x transverse diameter of cranium
+- ## Imaging
+  
+  
+    - 3D FIESTA/CISS
+          - Acquire in sagittal plane to outline aqueduct
+    - Limited shunt MR protocol
+          - 30-second acquisition in each plane
+          - Useful substitute for CT
+          - Insensitive for parenchymal abnormalities
+- ## Pathology
+  
+  
+    - Extracellular, extravascular fluid in brain is managed by glymphatic system
+          - CSF circulates from within ventricles → subarachnoid space → perivascular spaces ↔ interstitium ↔ perivenular spaces → subarachnoid space
+          - CSF is resorbed from subarachnoid space at multiple sites
+                  - Along sheaths of cranial nerves (especially olfactory bulb) into head and neck lymphatics
+                  - Along sheaths of spinal nerves into perispinal lymphatics
+                  - Into meningeal (dural) lymphatics
+                  - Into dural sinuses via arachnoid granulations
+                            - Previously thought to be major site of resorption
+    - Hydrocephalus results from obstruction of CSF egress from ventricular system or reduced resorption from subarachnoid space
+
+# TERMINOLOGY
+
+- ## Abbreviations
+  
+  
+    - Intraventricular obstructive hydrocephalus (IVOH)
+          - Acute IVOH (aIVOH)
+          - Chronic "compensated" IVOH (cIVOH)
+    - Extraventricular obstructive hydrocephalus (EVOH)
+    - Frontal occipital horn ratio (FOHR)
+          - (Transverse diameter of frontal horns + transverse diameter of occipital horns) ÷ 2x transverse diameter of cranium
+    - Subarachnoid lymphatic-like membrane (SLYM)
+          - Recently discovered 4th meningeal membrane that divides subarachnoid space into inner and outer compartments
+- ## Definitions
+  
+  
+    - Ventriculomegaly caused by
+          - Obstruction of CSF egress from ventricles: IVOH
+          - Decreased CSF resorption from subarachnoid space: EVOH
+          - Increased CSF production
+    - Ventriculomegaly secondary to loss of parenchyma, a.k.a. ex vacuo dilation, is **not**hydrocephalus
+
+# IMAGING
+
+- ## General Features
+  
+  
+    - ### Best diagnostic clue
+      
+      
+          - Enlarged ventricles
+                  - With decreased extraaxial spaces (EAS): IVOH
+                  - With periventricular (transependymal) edema: Acute IVOH
+                  - With enlarged EAS: EVOH
+    - ### Size
+      
+      
+          - FOHR > 0.33
+          - Temporal horn width > 3 mm
+    - ### Morphology
+      
+      
+          - Ventricles proximal to obstruction enlarge, appear more rounded
+          - Trigones and occipital horns typically enlarge most
+                  - Wall pressure is proportional to diameter: Laplace law
+                  - Optic and infundibular recesses of 3rd ventricle may preferentially enlarge
+                  - Optic nerve sheaths may enlarge → papilledema
+- ## CT Findings
+  
+  
+    - ### NECT
+      
+      
+          - Large ventricles proximal to obstruction
+                  - aIVOH
+                            - "Ballooned" ventricles with periventricular low-density "halo"
+                  - cIVOH
+                            - "Ballooned" ventricles, periventricular "halo"
+          - Basal cisterns, sulci compressed/obliterated
+- ## MR Findings
+  
+  
+    - ### T1WI
+      
+      
+          - Lateral ventricles enlarged
+          - Corpus callosum (CC) thinned, stretched upward
+                  - May be impinged against falx
+                  - Impaction may cause pressure necrosis
+          - Fornix, internal cerebral veins (ICV) displaced downward
+          - Enlarged 3rd ventricle often herniated into expanded sella
+          - Funnel-shaped aqueduct of Sylvius in aqueductal stenosis
+    - ### T2WI
+      
+      
+          - Acute obstruction
+                  - Transependymal edema extends into periventricular white matter (WM)
+                            - Accentuated around frontal and occipital horns
+          - Chronic obstruction
+                  - Large ventricles without transependymal edema
+                  - CC may show hyperintensity after decompression (15% of shunted IVOH cases)
+    - ### T1WI C+
+      
+      
+          - Diffuse leptomeningeal disease can cause EVOH
+                  - May only be apparent on postcontrast imaging
+    - ### MRS
+      
+      
+          - Small lactate resonances can be detected in up to 20% of CSF spaces, even if no hydrocephalus
+- ## Other Modality Findings
+  
+  
+    - Contrast-enhanced ventriculography
+          - MR/CT used to identify site of obstruction, status of 3rd ventriculostomies
+          - MR can be used for assessing CSF flow
+    - Cardiac-gated phase-contrast MR
+          - May show loss of CSF flow through aqueduct
+          - Useful for assessing status of endoscopic 3rd ventriculostomy (ETV)
+- ## Imaging Recommendations
+  
+  
+    - ### Best imaging tool
+      
+      
+          - Sagittal T2WI MR
+          - Administer contrast if pattern suggests EVOH and no etiology is apparent
+    - ### Protocol advice
+      
+      
+          - 3D FIESTA/CISS
+                  - Acquire in sagittal plane to outline aqueduct
+                  - Decreases CSF flow artifact
+                  - Allows better delineation of ventricular contour, septa
+          - SWI to assess for superficial siderosis in posthemorrhagic hydrocephalus
+          - Limited shunt MR protocol
+                  - Single-shot rapid technique with heavy T2 weighting
+                  - 30-second acquisition in each plane
+                  - Useful substitute for CT
+                            - Reduce radiation exposure in frequently imaged population
+                            - Rapid aquisition reduces need for sedation
+                  - Insensitive for parenchymal abnormalities
+          - Use FOHR to track ventricle size over time
+                  - Especially in younger children with open sutures
+                  - Accounts for increase in head circumference with increase in ventricular size
+
+# DIFFERENTIAL DIAGNOSIS
+
+- ## Ventricular Enlargement Secondary to Parenchymal Loss
+  
+  
+    - a.k.a. ex vacuo ventriculomegaly
+    - Age related (ventricular volume increases 1.2-1.4 mL after 60 years)
+          - Ischemia/infarction, trauma, infection, toxic
+    - Obtuse frontal angle (> 110°)
+    - Associated enlargement of sulci, cisterns
+    - Normal lateral ventricles can be asymmetric
+- ## Benign Enlargement of Subarachnoid Spaces and Ventricles
+  
+  
+    - a.k.a. benign macrocrania
+    - Seen in association with macrocephaly in infants
+    - Transient and self-limited
+          - Not associated with developmental delay
+          - Does not require CSF diversion
+    - Likely reflects relative immaturity of glymphatic system
+          - Diminished ability to resorb CSF as interstitial fluid compartment is shrunk by progressive myelination
+
+# PATHOLOGY
+
+- ## General Features
+  
+  
+    - ### Etiology
+      
+      
+          - Extracellular, extravascular fluid in brain is managed by glymphatic system
+                  - Maintains homeostatic balance between interstitial fluid compartment, cellular compartment, and intravascular compartment
+                  - Analogous to lymphatic system in other organs
+          - While brain parenchyma does not have lymphatic vessels, they are present in dura mater and along sheaths of cranial nerves
+          - CSF circulates from within ventricles → subarachnoid space → perivascular spaces ↔ interstitium ↔ perivenular spaces → subarachnoid space
+          - CSF is resorbed from subarachnoid space at multiple sites
+                  - Along sheaths of cranial nerves (especially olfactory bulb) into head and neck lymphatics
+                  - Along sheaths of spinal nerves into perispinal lymphatics
+                  - Into meningeal (dural) lymphatics
+                  - Into dural sinuses via arachnoid granulations
+                            - Previously thought to be major site of resorption
+          - SLYM is thought to facilitate CSF flow
+                  - Disruption after trauma may explain reduced glymphatic flow and posttraumatic cerebral edema
+          - Normal CSF production = 0.2-0.35 mL/min
+                  - Capacity of lateral, 3rd ventricles in adult = 20 mL
+                  - Total volume of CSF in adult = 120 mL
+          - Hydrocephalus results from obstruction of CSF egress from ventricular system or reduced resorption from subarachnoid space
+          - Obstruction within ventricular system results in IVOH
+                  - Ventricles expand, compress adjacent parenchyma; stretching may rupture/open ependymal cell junctions
+                  - Periventricular interstitial fluid increases → myelin destruction
+          - Etiology depends on site
+                  - Foramen of Monro
+                            - Colloid cyst
+                            - Subependymal giant cell astrocytoma in tuberous sclerosis
+                  - 3rd ventricle
+                            - Craniopharyngioma, hypothalamic glioma, arachnoid cyst
+                  - Aqueduct of Sylvius
+                            - Aqueductal stenosis, tectal glioma, pineal region tumor
+                            - Obstruction by hemorrhage or inflammatory debris
+                            - Enlarged vein of Galen due to arteriovenous fistula
+                  - 4th ventricle
+                            - Medulloblastoma, ependymoma, pilocytic astrocytoma
+                            - Chiari, Dandy-Walker malformation, Blake pouch cyst
+                  - Metastasis, neurocysticercosis, or meningioma can occur at multiple intraventricular locations
+          - Reduced resorption from subarachnoid space results in EVOH
+                  - Subarachnoid pathology may reduce absorptive capacity
+                            - Hemorrhage or inflammation (acute or chronic)
+                  - Metabolic disorders may reduce resorptive capacity
+          - Overproduction of CSF may overwhelm ability of glymphatic system to manage and resorb CSF
+                  - Choroid plexus papilloma or carcinoma
+                            - Focally enlarged and hyperenhancing choroidal mass
+                  - Choroid plexus villous hyperplasia
+                            - Diffusely enlarged choroid
+    - ### Genetics
+      
+      
+          - Cell adhesion molecule L1 (*L1CAM*) recognized as cause of X-linked aqueductal stenosis
+                  - Located on X chromosome (Xq28)
+- ## Gross Pathologic & Surgical Features
+  
+  
+    - Focal/generalized ventricular enlargement
+    - Ependyma, adjacent WM are secondarily injured
+    - Variable pathology depending on causative factor
+
+# CLINICAL ISSUES
+
+- ## Presentation
+  
+  
+    - ### Most common signs/symptoms
+      
+      
+          - Headache, papilledema (aIVOH)
+          - Nausea, vomiting
+          - Diplopia
+                  - 6th nerve palsy caused by compression of cisternal segment
+    - ### Clinical profile
+      
+      
+          - Varies with etiology, severity, age of onset
+- ## Demographics
+  
+  
+    - ### Age
+      
+      
+          - May be any age from in utero (congenital hydrocephalus) to adult
+    - ### Epidemiology
+      
+      
+          - Epidemiological data varies widely, depending upon etiology and type of hydrocephalus
+- ## Natural History & Prognosis
+  
+  
+    - Usually progressive unless treated
+- ## Treatment
+  
+  
+    - Obstructive hydrocephalus is managed surgically
+          - CSF diversion (shunt or ETV)
+          - Resection of obstructing or hypersecreting lesion
+    - Most common neurosurgical procedure in children = CSF shunting for hydrocephalus
+    - CSF diversion is typically delayed in EVOH
+          - Tendency to be much more shunt dependent
+                  - Less tolerant of minor pressure changes
+          - Lesser degree of ventriculomegaly increases difficulty of surgery
+
+# DIAGNOSTIC CHECKLIST
+
+- ## Consider
+  
+  
+    - Longstanding aqueductal stenosis can be caused by slow-growing tectal tumor
+          - Compensated IVOH
+    - CSF function and homeostasis are far more complex than previously thought
+          - Free communication among anatomic/functional compartments is necessary for proper brain health
+- ## Image Interpretation Pearls
+  
+  
+    - Size of ventricles generally correlates poorly with intracranial pressure
+    - Pulsatile CSF may create confusing signal intensity, even mimic intraventricular mass
+
+ cf76a2a7-da6e-419b-9e56-481a10e5b803
+
+## References
+
+# Selected References
+
+1. [Møllgård K et al: A mesothelium divides the subarachnoid space into functional compartments. Science. 379(6627):84-8, 2023](http://www.ncbi.nlm.nih.gov/pubmed/?term=36603070%5Bpmid%5D)
+1. [Krishnan P et al: Neuroimaging in pediatric hydrocephalus. Indian J Pediatr. 86(10):952-60, 2019](http://www.ncbi.nlm.nih.gov/pubmed/?term=31077004%5Bpmid%5D)
+1. [Ha SK et al: Magnetic resonance imaging and histopathological visualization of human dural lymphatic vessels. Bio Protoc. 8(8), 2018](http://www.ncbi.nlm.nih.gov/pubmed/?term=29780855%5Bpmid%5D)
+1. [Patel SK et al: Advanced neuroimaging techniques in pediatric hydrocephalus. Pediatr Neurosurg. 52(6):436-45, 2017](http://www.ncbi.nlm.nih.gov/pubmed/?term=28095378%5Bpmid%5D)
+1. [Algin O et al: Assessment of third ventriculostomy patency with the 3D-SPACE technique: a preliminary multicenter research study. J Neurosurg. 122(6):1347-55, 2015](http://www.ncbi.nlm.nih.gov/pubmed/?term=25859808%5Bpmid%5D)
+1. [Jessen NA et al: The glymphatic system: a beginner's guide. Neurochem Res. 40(12):2583-99, 2015](http://www.ncbi.nlm.nih.gov/pubmed/?term=25947369%5Bpmid%5D)
+1. [Russo N et al: Endoscopic approaches to intraventricular lesions. J Neurol Surg A Cent Eur Neurosurg. 76(5):353-60, 2015](http://www.ncbi.nlm.nih.gov/pubmed/?term=26008954%5Bpmid%5D)
+1. [Flannery AM et al: Pediatric hydrocephalus: systematic literature review and evidence-based guidelines. Part 1: introduction and methodology. J Neurosurg Pediatr. 14 Suppl 1:3-7, 2014](http://www.ncbi.nlm.nih.gov/pubmed/?term=25988777%5Bpmid%5D)
+1. [Mazzola CA et al: Pediatric hydrocephalus: systematic literature review and evidence-based guidelines. Part 2: management of posthemorrhagic hydrocephalus in premature infants. J Neurosurg Pediatr. 14 Suppl 1:8-23, 2014](http://www.ncbi.nlm.nih.gov/pubmed/?term=25988778%5Bpmid%5D)
+1. [Nikas DC et al: Pediatric hydrocephalus: systematic literature review and evidence-based guidelines. Part 10: change in ventricle size as a measurement of effective treatment of hydrocephalus. J Neurosurg Pediatr. 14 Suppl 1:77-81, 2014](http://www.ncbi.nlm.nih.gov/pubmed/?term=25988786%5Bpmid%5D)
+1. [Dinçer A et al: Radiologic evaluation of pediatric hydrocephalus. Childs Nerv Syst. 27(10):1543-62, 2011](http://www.ncbi.nlm.nih.gov/pubmed/?term=21928020%5Bpmid%5D)
+1. [Mirone G et al: Hydrocephalus and spinal cord tumors: a review. Childs Nerv Syst. 27(10):1741-9, 2011](http://www.ncbi.nlm.nih.gov/pubmed/?term=21928038%5Bpmid%5D)
+1. [Oi S: Classification of hydrocephalus: critical analysis of classification categories and advantages of "Multi-categorical Hydrocephalus Classification" (Mc HC). Childs Nerv Syst. 27(10):1523-33, 2011](http://www.ncbi.nlm.nih.gov/pubmed/?term=21928018%5Bpmid%5D)
+1. [Dinçer A et al: Is all "communicating" hydrocephalus really communicating? Prospective study on the value of 3D-constructive interference in steady state sequence at 3T. AJNR Am J Neuroradiol. 30(10):1898-906, 2009](http://www.ncbi.nlm.nih.gov/pubmed/?term=19643921%5Bpmid%5D)
+1. [Feng F et al: Evaluation of radionuclide cerebrospinal fluid scintigraphy as a guide in the management of patients with hydrocephalus. Clin Imaging. 33(2):85-9, 2009](http://www.ncbi.nlm.nih.gov/pubmed/?term=19237049%5Bpmid%5D)
+1. [Linninger AA et al: Normal and hydrocephalic brain dynamics: the role of reduced cerebrospinal fluid reabsorption in ventricular enlargement. Ann Biomed Eng. 37(7):1434-47, 2009](http://www.ncbi.nlm.nih.gov/pubmed/?term=19373558%5Bpmid%5D)
+1. [Oertel JM et al: Endoscopic third ventriculostomy in obstructive hydrocephalus due to giant basilar artery aneurysm. J Neurosurg. 110(1):14-8, 2009](http://www.ncbi.nlm.nih.gov/pubmed/?term=18991498%5Bpmid%5D)
+1. [Stoquart-El Sankari S et al: Phase-contrast MR imaging support for the diagnosis of aqueductal stenosis. AJNR Am J Neuroradiol. 30(1):209-14, 2009](http://www.ncbi.nlm.nih.gov/pubmed/?term=18832663%5Bpmid%5D)
+1. [Sekula RF Jr et al: A case of an elderly adult presenting with obstructive hydrocephalus secondary to a rare hemorrhagic suprasellar pilocytic astrocytoma. Clin Neuropathol. 27(6):396-9, 2008](http://www.ncbi.nlm.nih.gov/pubmed/?term=19130737%5Bpmid%5D)
+1. [Yamada S et al: Visualization of cerebrospinal fluid movement with spin labeling at MR imaging: preliminary results in normal and pathophysiologic conditions. Radiology. 249(2):644-52, 2008](http://www.ncbi.nlm.nih.gov/pubmed/?term=18936318%5Bpmid%5D)
+1. [Erdogan AR et al: Sex and handedness differences in size of cerebral ventricles of normal subjects. Int J Neurosci. 114(1):67-73, 2004](http://www.ncbi.nlm.nih.gov/pubmed/?term=14660068%5Bpmid%5D)
+1. [Gaser C et al: Ventricular enlargement in schizophrenia related to volume reduction of the thalamus, striatum, and superior temporal cortex. Am J Psychiatry. 161(1):154-6, 2004](http://www.ncbi.nlm.nih.gov/pubmed/?term=14702264%5Bpmid%5D)
+1. [Wyldes M et al: Isolated mild fetal ventriculomegaly. Arch Dis Child Fetal Neonatal Ed. 89(1):F9-13, 2004](http://www.ncbi.nlm.nih.gov/pubmed/?term=14711845%5Bpmid%5D)
+1. [Akhondi H et al: Hydrocephalus as a presenting manifestation of neurosarcoidosis. South Med J. 96(4):403-6, 2003](http://www.ncbi.nlm.nih.gov/pubmed/?term=12916562%5Bpmid%5D)
+1. [Bhattacharyya KB et al: Bobble-head doll syndrome: some atypical features with a new lesion and review of the literature. Acta Neurol Scand. 108(3):216-20, 2003](http://www.ncbi.nlm.nih.gov/pubmed/?term=12911467%5Bpmid%5D)
+1. Brown KP et al: 1H MRS in human hydrocephalus. J MRI. 14:291-9, 2003
+1. [Grunert P et al: The role of third ventriculostomy in the management of obstructive hydrocephalus. Minim Invasive Neurosurg. 46(1):16-21, 2003](http://www.ncbi.nlm.nih.gov/pubmed/?term=12640578%5Bpmid%5D)
+1. [Joseph VB et al: MR ventriculography for the study of CSF flow. AJNR Am J Neuroradiol. 24(3):373-81, 2003](http://www.ncbi.nlm.nih.gov/pubmed/?term=12637285%5Bpmid%5D)
+1. [Sener RN: Callosal changes in obstructive hydrocephalus: observations with FLAIR imaging, and diffusion MRI. Comput Med Imaging Graph. 26(5):333-7, 2002](http://www.ncbi.nlm.nih.gov/pubmed/?term=12204238%5Bpmid%5D)
+
+
+## Images
+
+
+### Selected Images
+
+![Depiction of normal CSF flow through the glymphatic system. CSF descends along periarterial perivascular spaces (PVS) and through the interstitium before exiting along perivenular PVS, clearing macromolecules (black particles). The exchange between interstitium and PVS is modulated by astrocytic endfeet expressing AQP4 (pink channels).](images/app.statdx.com_image_thumbnail_e84cc4eb-f65b-49c8-8023-d157ef9155ba_annotated_true_size_900_quality_90_1b92eb51_20251018T164957Z.jpg)
+*Depiction of normal CSF flow through the glymphatic system. CSF descends along periarterial perivascular spaces (PVS) and through the interstitium before exiting along perivenular PVS, clearing macromolecules (black particles). The exchange between interstitium and PVS is modulated by astrocytic endfeet expressing AQP4 (pink channels).*
+
+![Depiction of normal CSF flow through the glymphatic system. CSF descends along periarterial perivascular spaces (PVS) and through the interstitium before exiting along perivenular PVS, clearing macromolecules (black particles). The exchange between interstitium and PVS is modulated by astrocytic endfeet expressing AQP4 (pink channels).](images/app.statdx.com_image_thumbnail_e84cc4eb-f65b-49c8-8023-d157ef9155ba_size_174_quality_85_184aa51d_20251018T155131Z.jpg)
+*Depiction of normal CSF flow through the glymphatic system. CSF descends along periarterial perivascular spaces (PVS) and through the interstitium before exiting along perivenular PVS, clearing macromolecules (black particles). The exchange between interstitium and PVS is modulated by astrocytic endfeet expressing AQP4 (pink channels).*
+
+![An isoattenuating colloid cyst <img src='/img/arrows/WC.png'/> obstructs the foramina of Monro in this 7-year-old, causing obstructive hydrocephalus.](images/app.statdx.com_image_thumbnail_dfa6cf57-4225-40b1-8037-f7f2557ee773_annotated_true_size_900_quality_90_b05cdf7d_20251018T164957Z.jpg)
+*An isoattenuating colloid cyst <img src='/img/arrows/WC.png'/> obstructs the foramina of Monro in this 7-year-old, causing obstructive hydrocephalus.*
+
+![A large suprasellar arachnoid cyst balloons upward <img src='/img/arrows/BS.png'/> and obstructs the foramina of Monro in this 1-year-old with macrocrania.](images/app.statdx.com_image_thumbnail_70070ccc-c977-4c05-a903-81616fbbea63_annotated_true_size_900_quality_90_dddf27ae_20251018T164957Z.jpg)
+*A large suprasellar arachnoid cyst balloons upward <img src='/img/arrows/BS.png'/> and obstructs the foramina of Monro in this 1-year-old with macrocrania.*
+
+![This 3-month-old with hydrocephalus has a Blake pouch cyst obstructing outflow of CSF from the 4th ventricle. Note the membrane across the posterior foramen magnum <img src='/img/arrows/CC.png'/> and the uplifting of the vermis <img src='/img/arrows/CO.png'/>.](images/app.statdx.com_image_thumbnail_310d1a62-4dbc-479a-9e9e-423205955735_annotated_true_size_900_quality_90_b75c461d_20251018T164957Z.jpg)
+*This 3-month-old with hydrocephalus has a Blake pouch cyst obstructing outflow of CSF from the 4th ventricle. Note the membrane across the posterior foramen magnum <img src='/img/arrows/CC.png'/> and the uplifting of the vermis <img src='/img/arrows/CO.png'/>.*
+
+![A medulloblastoma <img src='/img/arrows/WO.png'/> fills and obstructs the 4th ventricle in this 10-year-old, leading to supratentorial ventriculomegaly and papilledema <img src='/img/arrows/BS.png'/>. Papilledema visible on MR typically correlates to grade 3 on the Frisen scale (moderate edema).](images/app.statdx.com_image_thumbnail_9a9c7b4f-95d2-4e4d-8b5d-68161defab53_annotated_true_size_900_quality_90_a79dce92_20251018T164957Z.jpg)
+*A medulloblastoma <img src='/img/arrows/WO.png'/> fills and obstructs the 4th ventricle in this 10-year-old, leading to supratentorial ventriculomegaly and papilledema <img src='/img/arrows/BS.png'/>. Papilledema visible on MR typically correlates to grade 3 on the Frisen scale (moderate edema).*
+
+![Axial FLAIR MR through the lateral ventricles in the same child shows transependymal edema capping the frontal and occipital horns <img src='/img/arrows/WO.png'/>, reflecting the increased pressure in the ventricular system.](images/app.statdx.com_image_thumbnail_d9d39656-21b9-48e2-82d3-86f3cabd705a_annotated_true_size_900_quality_90_91b55c48_20251018T164957Z.jpg)
+*Axial FLAIR MR through the lateral ventricles in the same child shows transependymal edema capping the frontal and occipital horns <img src='/img/arrows/WO.png'/>, reflecting the increased pressure in the ventricular system.*
+
+![Bacterial meningitis (group A Streptococcus in this example) can restrict resorption of CSF but can also obstruct at the cerebral aqueduct and 4th ventricular outlets when complicated by ventriculitis, evident on this image by abnormal enhancement of the ependyma <img src='/img/arrows/WO.png'/>.](images/app.statdx.com_image_thumbnail_e5af07e5-9045-454e-919f-bb1cfd505bdc_annotated_true_size_900_quality_90_bee3db67_20251018T164957Z.jpg)
+*Bacterial meningitis (group A Streptococcus in this example) can restrict resorption of CSF but can also obstruct at the cerebral aqueduct and 4th ventricular outlets when complicated by ventriculitis, evident on this image by abnormal enhancement of the ependyma <img src='/img/arrows/WO.png'/>.*
+
+![An infiltrating tectal glioma <img src='/img/arrows/WS.png'/> obstructs the cerebral aqueduct in this 10-year-old. Absence of transependymal edema suggests a compensated hydrocephalus.](images/app.statdx.com_image_thumbnail_0e5ef294-c697-4d00-9852-0ad6f730f900_annotated_true_size_900_quality_90_68db5118_20251018T164957Z.jpg)
+*An infiltrating tectal glioma <img src='/img/arrows/WS.png'/> obstructs the cerebral aqueduct in this 10-year-old. Absence of transependymal edema suggests a compensated hydrocephalus.*
+
+![A papilloma of the choroid plexus in the occipital horn of the left lateral ventricle <img src='/img/arrows/WS.png'/> causes moderate hydrocephalus by excessive CSF production in this 2-month-old.](images/app.statdx.com_image_thumbnail_3404043a-6569-4de0-b4a3-a0cc0bd2b6dc_annotated_true_size_900_quality_90_aa2614f3_20251018T164957Z.jpg)
+*A papilloma of the choroid plexus in the occipital horn of the left lateral ventricle <img src='/img/arrows/WS.png'/> causes moderate hydrocephalus by excessive CSF production in this 2-month-old.*
+
+![CSF overproduction can rarely be nonneoplastic in nature, as in this 6-month-old with villous hyperplasia of the choroid plexus in each lateral ventricle <img src='/img/arrows/BS.png'/>. Note the preservation of peripheral sulci, as the unfused sutures of the infant can widen in response to increased intracranial volume.](images/app.statdx.com_image_thumbnail_e380d6ae-5d60-44e2-bf15-30137880085f_annotated_true_size_900_quality_90_1fe1546a_20251018T164959Z.jpg)
+*CSF overproduction can rarely be nonneoplastic in nature, as in this 6-month-old with villous hyperplasia of the choroid plexus in each lateral ventricle <img src='/img/arrows/BS.png'/>. Note the preservation of peripheral sulci, as the unfused sutures of the infant can widen in response to increased intracranial volume.*
+
+
+### Additional Images
+
+![Sagittal T1 MR shows a large mass within the 4th ventricle <img src='/img/arrows/BO.png'/> causing intraventricular obstructive hydrocephalus or noncommunicating hydrocephalus.](images/app.statdx.com_image_thumbnail_c48f3e2e-092c-4ce3-881e-9a269ec15ea6_annotated_true_size_900_quality_90_78b02641_20251018T165000Z.jpg)
+*Sagittal T1 MR shows a large mass within the 4th ventricle <img src='/img/arrows/BO.png'/> causing intraventricular obstructive hydrocephalus or noncommunicating hydrocephalus.*
+
+![Sagittal T2 MR in the same patient shows transependymal CSF flow, seen here as &quot;fingers&quot; extending into white matter around the enlarged lateral ventricle. The case was medulloblastoma with acute IVOH.](images/app.statdx.com_image_thumbnail_15897f20-57e8-4b17-9ac4-30cab6467abb_annotated_true_size_900_quality_90_9fed6b74_20251018T165000Z.jpg)
+*Sagittal T2 MR in the same patient shows transependymal CSF flow, seen here as &quot;fingers&quot; extending into white matter around the enlarged lateral ventricle. The case was medulloblastoma with acute IVOH.*
+
+![Coronal T1 C+ MR shows IVOH with a large, enhancing intraventricular mass <img src='/img/arrows/BS.png'/> causing marked enlargement of the lateral ventricles <img src='/img/arrows/WS.png'/>.](655689cf-c7a3-44eb-85b1-9c92f7dc0cb1)
+*Coronal T1 C+ MR shows IVOH with a large, enhancing intraventricular mass <img src='/img/arrows/BS.png'/> causing marked enlargement of the lateral ventricles <img src='/img/arrows/WS.png'/>.*
+
+![Axial NECT in the same patient shows the large intraventricular mass <img src='/img/arrows/BS.png'/> within the 4th ventricle. Note the dilated temporal horns <img src='/img/arrows/WS.png'/>.](images/app.statdx.com_image_thumbnail_1d873379-77f2-4ba4-85c9-43715aedaedc_annotated_true_size_900_quality_90_092a91f4_20251018T165000Z.jpg)
+*Axial NECT in the same patient shows the large intraventricular mass <img src='/img/arrows/BS.png'/> within the 4th ventricle. Note the dilated temporal horns <img src='/img/arrows/WS.png'/>.*
+
+![Sagittal T1 MR shows IVOH secondary to aqueductal stenosis and distal stenosis of cerebral aqueduct <img src='/img/arrows/BC.png'/>. Note the enlarged lateral and 3rd ventricles.](images/app.statdx.com_image_thumbnail_e2d6cb01-32da-4284-85fb-e1d0b11218b1_annotated_true_size_900_quality_90_168d3b76_20251018T165000Z.jpg)
+*Sagittal T1 MR shows IVOH secondary to aqueductal stenosis and distal stenosis of cerebral aqueduct <img src='/img/arrows/BC.png'/>. Note the enlarged lateral and 3rd ventricles.*
+
+![Axial FLAIR MR shows neurosarcoidosis and EVOH secondary to diffuse meningeal disease. Periventricular white matter hyperintensities <img src='/img/arrows/BS.png'/> are also present, as well as choroid involvement <img src='/img/arrows/WO.png'/>.](images/app.statdx.com_image_thumbnail_f9368bc3-dfdf-4912-bb77-5097bb5043bb_annotated_true_size_900_quality_90_45550aa6_20251018T165000Z.jpg)
+*Axial FLAIR MR shows neurosarcoidosis and EVOH secondary to diffuse meningeal disease. Periventricular white matter hyperintensities <img src='/img/arrows/BS.png'/> are also present, as well as choroid involvement <img src='/img/arrows/WO.png'/>.*
+
+![Coronal T1 C+ MR shows neurocysticercosis involvement within the 3rd ventricle and aqueduct <img src='/img/arrows/BS.png'/>, causing IVOH. The lateral ventricles are dilated.](images/app.statdx.com_image_thumbnail_be2f5692-eeeb-4ea0-aae2-9ececaf9072b_annotated_true_size_900_quality_90_31f0b627_20251018T165000Z.jpg)
+*Coronal T1 C+ MR shows neurocysticercosis involvement within the 3rd ventricle and aqueduct <img src='/img/arrows/BS.png'/>, causing IVOH. The lateral ventricles are dilated.*
+
+![Axial FLAIR MR shows neurocysticercosis resulting in IVOH. Large intraventricular cysts are present in the lateral vents <img src='/img/arrows/BS.png'/>, obstructing the foramina of Monro.](images/app.statdx.com_image_thumbnail_d4fbed45-ded4-4557-8a60-ffa2c5a76b7b_annotated_true_size_900_quality_90_b7584229_20251018T165001Z.jpg)
+*Axial FLAIR MR shows neurocysticercosis resulting in IVOH. Large intraventricular cysts are present in the lateral vents <img src='/img/arrows/BS.png'/>, obstructing the foramina of Monro.*
+
+![Axial T1 MR shows a well-defined, hyperintense lesion <img src='/img/arrows/BO.png'/> at the foramen of Monro in a patient with headaches, most consistent with a colloid cyst. Note the enlargement of the lateral ventricles <img src='/img/arrows/BC.png'/> due to obstruction at the foramen of Monro.](images/app.statdx.com_image_thumbnail_709fe152-548b-43c9-a72d-d13abe331723_annotated_true_size_900_quality_90_9f3616ed_20251018T165001Z.jpg)
+*Axial T1 MR shows a well-defined, hyperintense lesion <img src='/img/arrows/BO.png'/> at the foramen of Monro in a patient with headaches, most consistent with a colloid cyst. Note the enlargement of the lateral ventricles <img src='/img/arrows/BC.png'/> due to obstruction at the foramen of Monro.*
+
+![Sagittal T1 C+ MR shows a homogeneously enhancing mass in the posterior 3rd ventricle <img src='/img/arrows/WO.png'/>, which causes obstruction and dilatation of the lateral and 3rd ventricles. On pathology, this was an astrocytoma.](images/app.statdx.com_image_thumbnail_f26e26ab-4622-4975-b3b8-c0241bd59f6e_annotated_true_size_900_quality_90_214d2580_20251018T165001Z.jpg)
+*Sagittal T1 C+ MR shows a homogeneously enhancing mass in the posterior 3rd ventricle <img src='/img/arrows/WO.png'/>, which causes obstruction and dilatation of the lateral and 3rd ventricles. On pathology, this was an astrocytoma.*
+
+![Coronal T2 MR shows a pilocytic astrocytoma centered in the right thalamus <img src='/img/arrows/CO.png'/>, causing severe mass effect on the 3rd ventricle <img src='/img/arrows/CS.png'/> and resultant obstructive hydrocephalus <img src='/img/arrows/WC.png'/>.](39ae17e4-a50a-4f11-b6c5-42b47b2c293a)
+*Coronal T2 MR shows a pilocytic astrocytoma centered in the right thalamus <img src='/img/arrows/CO.png'/>, causing severe mass effect on the 3rd ventricle <img src='/img/arrows/CS.png'/> and resultant obstructive hydrocephalus <img src='/img/arrows/WC.png'/>.*
+
+![Axial T2 MR demonstrates a well-defined CSF intensity cyst with the left temporal horn most consistent with an ependymal cyst <img src='/img/arrows/BO.png'/>. Note the dilated and trapped left temporal horn <img src='/img/arrows/BS.png'/>.](c1b16bae-b36a-4bf1-8de9-ca410a8c3f96)
+*Axial T2 MR demonstrates a well-defined CSF intensity cyst with the left temporal horn most consistent with an ependymal cyst <img src='/img/arrows/BO.png'/>. Note the dilated and trapped left temporal horn <img src='/img/arrows/BS.png'/>.*
+
+![Sagittal T1 C+ MR shows an enhancing mass in the pineal region <img src='/img/arrows/BS.png'/> causing mass effect on the tectal plate and aqueductal obstruction. Note the extensive leptomeningeal enhancement due to CSF spread of tumor. CSF cytology showed a primitive neuroectodermal tumor.](8096e72c-52bb-4372-a469-ed9b3c222bd4)
+*Sagittal T1 C+ MR shows an enhancing mass in the pineal region <img src='/img/arrows/BS.png'/> causing mass effect on the tectal plate and aqueductal obstruction. Note the extensive leptomeningeal enhancement due to CSF spread of tumor. CSF cytology showed a primitive neuroectodermal tumor.*
+
+![A medulloblastoma <img src='/img/arrows/WO.png'/> fills and obstructs the 4th ventricle in this 10-year-old, leading to supratentorial ventriculomegaly and papilledema.](a7643e46-4a5e-47f0-b843-87e9f35fca31)
+*A medulloblastoma <img src='/img/arrows/WO.png'/> fills and obstructs the 4th ventricle in this 10-year-old, leading to supratentorial ventriculomegaly and papilledema.*
+
+![FIESTA shows pineal parenchymal tumor of intermediate differentiation <img src='/img/arrows/WO.png'/> obstructing the cerebral aqueduct in this 8-year-old boy.](229bee91-b7b6-4584-97a3-e6f656b0000c)
+*FIESTA shows pineal parenchymal tumor of intermediate differentiation <img src='/img/arrows/WO.png'/> obstructing the cerebral aqueduct in this 8-year-old boy.*
+

docs_md/articles/idiopathic-intracranial-hypertension_d7a0a1b6-1d94-473c-9fe9-021443969f9f.md

@@ -0,0 +1,428 @@
+---
+title: "Idiopathic Intracranial Hypertension"
+docid: "d7a0a1b6-1d94-473c-9fe9-021443969f9f"
+authors:
+  - key: "a25c450b-3d34-4f64-bba3-cc0834813df6"
+    value: "Miral D. Jhaveri, MD, MBA"
+breadcrumbs:
+  -
+    name: "Brain"
+    slug: "brain"
+    treeNodeId: "6d8829f1-14d7-45af-8675-255189aa526a"
+  -
+    name: "Diagnosis"
+    slug: "diagnosis"
+    treeNodeId: "51c00394-446e-4a38-94af-d3b1d14d34e8"
+  -
+    name: "Anatomy-Based Diagnoses"
+    slug: "anatomy-based-diagnoses"
+    treeNodeId: "529d3e33-f508-498c-bc70-cf962e81e629"
+  -
+    name: "Ventricles and Cisterns"
+    slug: "ventricles-and-cisterns"
+    treeNodeId: "33b267f0-908c-4c77-81f8-f6135d1bc592"
+  -
+    name: "CSF Disorders"
+    slug: "csf-disorders"
+    treeNodeId: "d305bd95-7cca-4888-80b9-fabe45d84ee5"
+  -
+    name: "Idiopathic Intracranial Hypertension"
+    slug: "idiopathic-intracranial-hypertensi-"
+    treeNodeId: null
+category: "Brain"
+documentVersionId: "8907806d-0770-46fa-b129-78e393ad4038"
+imageCount: 22
+lastUpdated: "10/08/20"
+pageDescription: "Idiopathic Intracranial Hypertension"
+pageKeywords: "Brain, Diagnosis, Anatomy-Based Diagnoses, Ventricles and Cisterns, CSF Disorders, Idiopathic Intracranial Hypertension"
+pageTitle: "Idiopathic Intracranial Hypertension | STATdx"
+enhancedTitle: "Idiopathic Intracranial Hypertension"
+type: "DX"
+references: true
+tables: 1
+breadcrumbs:
+  - "Brain"
+  - "Diagnosis"
+  - "Anatomy-Based Diagnoses"
+  - "Ventricles and Cisterns"
+  - "CSF Disorders"
+  - "Idiopathic Intracranial Hypertension"
+---
+# KEY FACTS
+
+- ## Terminology
+  
+  
+    - Idiopathic intracranial hypertension (IIH)
+    - Pseudotumor cerebri
+    - Benign intracranial hypertension
+    - ↑ intracranial pressure (ICP) without identifiable cause
+- ## Imaging
+  
+  
+    - Empty or partially empty sella
+    - Posterior globe flattening
+    - Intraocular protrusion of optic nerve head
+    - Optic nerve sheath enlargement ± tortuosity
+    - Optic nerve head DWI hyperintensity, ± enhancement
+    - Slit-like ventricles, rare: Poor neuroimaging sign of IIH
+    - MRV: Often shows transverse sinus stenosis and flow gaps
+          - Whether this is cause or consequence of raised ICP is controversial
+    - Best imaging tool: MR brain + T2 coronal fat-saturated orbit + MRV
+- ## Top Differential Diagnoses
+  
+  
+    - Secondary pseudotumor syndromes
+    - Idiopathic or postinflammatory (i.e., multiple sclerosis) optic nerve atrophy
+    - Idiopathic empty sella (normal variant)
+    - Chiari 1 malformation
+- ## Clinical Issues
+  
+  
+    - Obese woman age 20-44 years with headache and papilledema most common presentation
+          - Headache in 75-94%
+          - Papilledema (bilateral optic nerve head swelling) virtually universal
+    - Progressive visual loss ± CNVI paresis, diplopia
+    - Chief hazard: Vision loss from chronic papilledema
+    - Treatment: Medical or surgical (lumbar puncture, shunt, optic nerve sheath fenestration)
+    - Stent placement in transverse sinus stenosis with significant pressure differentials across stenosis (controversial)
+
+# TERMINOLOGY
+
+- ## Abbreviations
+  
+  
+    - Idiopathic intracranial hypertension (IIH)
+- ## Synonyms
+  
+  
+    - Pseudotumor cerebri
+    - Benign intracranial hypertension
+- ## Definitions
+  
+  
+    - ↑ intracranial pressure (ICP) without identifiable cause
+    - Association of any medication or condition with IIH better termed "secondary intracranial hypertension"
+
+# IMAGING
+
+- ## General Features
+  
+  
+    - ### Best diagnostic clue
+      
+      
+          - Flattening of posterior sclera, intraocular optic nerve protrusion, enlarged optic nerve sheath, ↑ tortuosity of optic nerve, partially empty sella, and venous sinus stenosis in patient with clinical findings of IIH
+    - Imaging in IIH
+          - Exclude identifiable causes of ↑ ICP
+          - Detect findings associated with IIH
+- ## CT Findings
+  
+  
+    - ### NECT
+      
+      
+          - Usually normal
+          - Enlarged optic nerve sheaths ± empty sella
+          - Less common: Slit ventricles
+    - ### Bone CT
+      
+      
+          - Solitary or multiple skull base osseous-dural defects
+          - May see skull base foramina enlargement
+- ## MR Findings
+  
+  
+    - ### T1WI
+      
+      
+          - Partially empty sella turcica
+          - Enlarged/tortuous optic nerve sheaths
+          - Posterior sclera flattened
+          - Small "pinched" ventricles
+          - Midline sagittal: Cerebellar tonsillar ectopia may mimic Chiari malformation type 1
+    - ### T2WI
+      
+      
+          - Empty or partially empty sella
+          - Posterior globe flattening
+          - Intraocular protrusion of optic nerve head
+          - Optic nerve sheath enlargement: Widened ring of CSF around optic nerve
+          - Optic nerve tortuosity
+          - Slit-like ventricles, rare: Poor neuroimaging sign of IIH
+          - "Tight" subarachnoid spaces
+          - Meningoencephaloceles
+    - ### FLAIR
+      
+      
+          - Contrast-enhanced 3D-FLAIR: Hyperintensity of optic nerve head sensitive for detection of papilledema in IIH
+    - ### DWI
+      
+      
+          - DWI hyperintensity of optic nerve head with papilledema
+          - DTI: Optic disc fractional anisotropy (FA) low & mean diffusivity (MD) high in IIH
+    - ### T1WI C+
+      
+      
+          - Enhancement of optic nerve head
+    - ### MRV
+      
+      
+          - Often shows transverse sinus stenosis and flow gaps
+          - Controversial whether this is cause or consequence of raised ICP
+    - CTV helpful to differentiate hypoplastic sinus segment from thrombosis
+- ## Imaging Recommendations
+  
+  
+    - ### Best imaging tool
+      
+      
+          - MR brain + T2 coronal fat-saturated orbit + MRV
+
+# DIFFERENTIAL DIAGNOSIS
+
+- ## Secondary Intracranial Hypertension
+  
+  
+    - Cerebral venous abnormalities
+          - [Dural venous sinus thrombosis, bilateral jugular vein thrombosis, superior vena cava syndrome, arteriovenous fistula](/document/dural-sinus-thrombosis/4e81a1de-df92-4172-99ec-1377b0d9d188)
+          - ↓ CSF absorption from previous intracranial infection or subarachnoid hemorrhage, hypercoagulable states
+                  - Ventriculomegaly more common
+    - Medications and exposures
+          - Tetracycline, minocycline, vitamin A, lithium, retinoids, anabolic steroids, withdrawal from chronic corticosteroids
+    - Medical conditions
+          - Endocrine disorders (Addison disease, hypoparathyroidism), hypercapnia, sleep apnea, SLE
+- [Idiopathic or Postinflammatory Optic Nerve Atrophy](/document/optic-neuritis/ac9c8fc9-33cd-4716-a509-2542ec5579ca)
+    - Small optic nerves without scleral flattening
+- [Idiopathic Empty Sella](/document/empty-sella/39a0d2d1-1439-4558-8f5d-86a2a6d93e3a)
+    - Normal variant; normal optic nerve sheaths
+- [Chiari 1 Malformation](/document/chiari-1-malformation/97837e15-0d39-4c87-8af0-028652b399a6)
+    - Peg-like tonsils ≥ 5 mm below foramen magnum
+    - Low cerebellar tonsils in IIH may mimic Chiari 1
+
+# PATHOLOGY
+
+- ## General Features
+  
+  
+    - ### Etiology
+      
+      
+          - Precise etiology of IIH unknown
+          - 5 different proposed mechanisms resulting in ↑ ICP
+                  - ↑ cerebral volume
+                            - Possible etiology: ↑ interstitial fluid, ↑ blood volume, ↑ tissue volume
+                  - ↑ CSF volume
+                            - Possible etiology: ↑ CSF production rate, ↑ CSF outflow resistance
+                  - ↑ cerebral arterial pressure
+                            - Possible etiology: Loss of cerebral autoregulation
+                  - ↑ venous blood volume and interstitial fluid
+                            - Possible etiology: ↑ cerebral venous pressure
+                  - ↓ CSF outflow and ↑ CSF volume
+- ## Gross Pathologic & Surgical Features
+  
+  
+    - Bilateral papilledema
+- ## Microscopic Features
+  
+  
+    - Normal CSF cytology, chemistry
+
+# CLINICAL ISSUES
+
+- ## Presentation
+  
+  
+    - ### Most common signs/symptoms
+      
+      
+          - Headache in 75-94%
+                  - Generalized, episodic, throbbing, aggravated by Valsalva
+          - Transient vision loss, other visual complaints
+                  - Fulminant IIH, severe vision loss < 4 weeks from onset of symptoms
+          - Papilledema (bilateral optic nerve head swelling) virtually universal
+          - Progressive visual loss ± CNVI paresis, diplopia
+          - Vertigo, tinnitus (52-60%), occasional pituitary dysfunction
+          - May present with spontaneous CSF leak
+                  - Some patient with spontaneous CSF leak may not exhibit typical symptoms of IIH
+                  - May develop symptoms of IIH after CSF leak repair
+          - Temporal lobe epilepsy caused by anteroinferior temporal lobe meningoencephaloceles in IIH
+    - ### Clinical profile
+      
+      
+          - Obese, young to middle-aged woman with headache, papilledema
+- ## Demographics
+  
+  
+    - ### Age
+      
+      
+          - Peak: 15-40 years (occasionally seen in children)
+    - ### Epidemiology
+      
+      
+          - 0.9 cases per 100,000 population in USA
+          - More common in overweight, reproductive-aged women
+          - Incidence in females aged 2-44 years & 20% above ideal body weight: ~ 19.3 cases per 100,000 population
+    - ### Sex
+      
+      
+          - M:F = 1:8
+    - Epidemiology: ↑ prevalence with obesity
+- ## Natural History & Prognosis
+  
+  
+    - Chief hazard: Vision loss from chronic papilledema, severe visual acuity deficits in 25% of patients without treatment
+- ## Treatment
+  
+  
+    - Goal: Prevent visual loss, improve associated symptoms
+    - Options
+          - Medical: Weight loss, carbonic anhydrase inhibitors: Acetazolamide
+          - Therapeutic lumbar puncture
+          - Surgical: Reserved for patients who continue to experience vision loss despite conservative management and those initially presenting with rapid vision loss
+                  - Lumboperitoneal shunt, optic nerve sheath fenestration
+          - Venous stent placement
+                  - Stent placement in transverse sinus stenosis with significant pressure differentials across stenosis has shown to improve symptoms and ↓ papilledema
+                  - ↓ cerebral venous pressure, improve CSF resorption in venous system: ↓ intracranial (CSF) pressure, improving symptoms of IIH, and ↓ papilledema
+                  - **Venous stent placement is controversial**
+
+# DIAGNOSTIC CHECKLIST
+
+- ## Image Interpretation Pearls
+  
+  
+    - Must exclude venous thrombosis/space-occupying lesion
+
+ 58e13d74-efc9-4630-9014-3c28122c7470
+
+## References
+
+# Selected References
+
+1. [Nagarajan E et al: Is magnetic resonance imaging diffusion restriction of the optic disc head a new marker for idiopathic intracranial hypertension? J Neurosci Rural Pract. 11(1):170-4, 2020](http://www.ncbi.nlm.nih.gov/pubmed/?term=32140023%5Bpmid%5D)
+1. [Boyter E: Idiopathic intracranial hypertension. JAAPA. 32(5):30-5, 2019](http://www.ncbi.nlm.nih.gov/pubmed/?term=30969189%5Bpmid%5D)
+1. [Golden E et al: Contrast-enhanced 3D-FLAIR imaging of the optic nerve and optic nerve head: novel neuroimaging findings of idiopathic intracranial hypertension. AJNR Am J Neuroradiol. 40(2):334-9, 2019](http://www.ncbi.nlm.nih.gov/pubmed/?term=30679213%5Bpmid%5D)
+1. [Rehder D: Idiopathic intracranial hypertension: review of clinical syndrome, imaging findings, and treatment. Curr Probl Diagn Radiol. ePub, 2019](http://www.ncbi.nlm.nih.gov/pubmed/?term=31056359%5Bpmid%5D)
+1. [Thurtell MJ: Idiopathic intracranial hypertension. Continuum (Minneap Minn). 25(5):1289-309, 2019](http://www.ncbi.nlm.nih.gov/pubmed/?term=31584538%5Bpmid%5D)
+1. [Madriz Peralta G et al: An update of idiopathic intracranial hypertension. Curr Opin Ophthalmol. 29(6):495-502, 2018](http://www.ncbi.nlm.nih.gov/pubmed/?term=30169466%5Bpmid%5D)
+1. [Stevens SM et al: Idiopathic intracranial hypertension: contemporary review and implications for the otolaryngologist. Laryngoscope. 128(1):248-56, 2018](http://www.ncbi.nlm.nih.gov/pubmed/?term=28349571%5Bpmid%5D)
+1. [Wall M: Update on idiopathic intracranial hypertension. Neurol Clin. 35(1):45-57, 2017](http://www.ncbi.nlm.nih.gov/pubmed/?term=27886895%5Bpmid%5D)
+1. [Görkem SB et al: MR imaging findings in children with pseudotumor cerebri and comparison with healthy controls. Childs Nerv Syst. 31(3):373-80, 2015](http://www.ncbi.nlm.nih.gov/pubmed/?term=25358812%5Bpmid%5D)
+1. [Masri A et al: Intracranial hypertension in children: etiologies, clinical features, and outcome. J Child Neurol. 30(12):1562-8, 2015](http://www.ncbi.nlm.nih.gov/pubmed/?term=25762586%5Bpmid%5D)
+1. [Sivasankar R et al: Imaging and interventions in idiopathic intracranial hypertension: a pictorial essay. Indian J Radiol Imaging. 25(4):439-44, 2015](http://www.ncbi.nlm.nih.gov/pubmed/?term=26752823%5Bpmid%5D)
+1. [Ahmed RM et al: Transverse sinus stenting for pseudotumor cerebri: a cost comparison with CSF shunting. AJNR Am J Neuroradiol. 35(5):952-8, 2014](http://www.ncbi.nlm.nih.gov/pubmed/?term=24287092%5Bpmid%5D)
+1. [Dave SB et al: Pseudotumor cerebri: an update on treatment options. Indian J Ophthalmol. 62(10):996-8, 2014](http://www.ncbi.nlm.nih.gov/pubmed/?term=25449933%5Bpmid%5D)
+1. [Liguori C et al: Revised diagnostic criteria for the pseudotumor cerebri syndrome in adults and children. Neurology. 82(19):1752-3, 2014](http://www.ncbi.nlm.nih.gov/pubmed/?term=24821936%5Bpmid%5D)
+1. [Friedman DI et al: Revised diagnostic criteria for the pseudotumor cerebri syndrome in adults and children. Neurology. 81(13):1159-65, 2013](http://www.ncbi.nlm.nih.gov/pubmed/?term=23966248%5Bpmid%5D)
+1. [Passi N et al: MR imaging of papilledema and visual pathways: effects of increased intracranial pressure and pathophysiologic mechanisms. AJNR Am J Neuroradiol. 34(5):919-24, 2013](http://www.ncbi.nlm.nih.gov/pubmed/?term=22422187%5Bpmid%5D)
+1. [Aiken AH et al: Incidence of cerebellar tonsillar ectopia in idiopathic intracranial hypertension: a mimic of the Chiari I malformation. AJNR Am J Neuroradiol. 33(10):1901-6, 2012](http://www.ncbi.nlm.nih.gov/pubmed/?term=22723059%5Bpmid%5D)
+1. [Ahmed RM et al: Transverse sinus stenting for idiopathic intracranial hypertension: a review of 52 patients and of model predictions. AJNR Am J Neuroradiol. 32(8):1408-14, 2011](http://www.ncbi.nlm.nih.gov/pubmed/?term=21799038%5Bpmid%5D)
+1. [Degnan AJ et al: Pseudotumor cerebri: brief review of clinical syndrome and imaging findings. AJNR Am J Neuroradiol. 32(11):1986-93, 2011](http://www.ncbi.nlm.nih.gov/pubmed/?term=21680652%5Bpmid%5D)
+1. [Furtado SV et al: Pseudotumor cerebri: as a cause for early deterioration after Chiari I malformation surgery. Childs Nerv Syst. 25(8):1007-12, 2009](http://www.ncbi.nlm.nih.gov/pubmed/?term=19296114%5Bpmid%5D)
+1. [Hershko AY et al: Increased intracranial pressure related to systemic lupus erythematosus: a 26-year experience. Semin Arthritis Rheum. 38(2):110-5, 2008](http://www.ncbi.nlm.nih.gov/pubmed/?term=18221986%5Bpmid%5D)
+1. [Randhawa S et al: Idiopathic intracranial hypertension (pseudotumor cerebri). Curr Opin Ophthalmol. 19(6):445-53, 2008](http://www.ncbi.nlm.nih.gov/pubmed/?term=18854688%5Bpmid%5D)
+1. [Agarwal MR et al: Optic nerve sheath fenestration for vision preservation in idiopathic intracranial hypertension. Neurosurg Focus. 23(5):E7, 2007](http://www.ncbi.nlm.nih.gov/pubmed/?term=18004969%5Bpmid%5D)
+1. [Binder DK et al: Idiopathic intracranial hypertension. Neurosurgery. 54(3):538-51; discussion 551-2, 2004](http://www.ncbi.nlm.nih.gov/pubmed/?term=15028127%5Bpmid%5D)
+1. [Bastin ME et al: Diffuse brain oedema in idiopathic intracranial hypertension: a quantitative magnetic resonance imaging study. J Neurol Neurosurg Psychiatry. 74(12):1693-6, 2003](http://www.ncbi.nlm.nih.gov/pubmed/?term=14638893%5Bpmid%5D)
+1. [Bandyopadhyay S: Pseudotumor cerebri. Arch Neurol. 58(10):1699-701, 2001](http://www.ncbi.nlm.nih.gov/pubmed/?term=11594936%5Bpmid%5D)
+1. [Suzuki H et al: MR imaging of idiopathic intracranial hypertension. AJNR Am J Neuroradiol. 22(1):196-9, 2001](http://www.ncbi.nlm.nih.gov/pubmed/?term=11158909%5Bpmid%5D)
+
+## Tables
+
+# Original Modified Dandy Criteria and Criteria Utilized in IIH Treatment Trial
+
+| A: Modified Dandy Criteria for IIH |
+| --- |
+| (1) Signs and symptoms of ↑ ICP (headaches, nausea, vomiting, transient visual obscurations, or papilledema) |
+| (2) Absence of localized findings in neurologic examination (except for false localizing signs, such as abducens nerve palsy) |
+| (3) Normal CT/MR findings without evidence of hydrocephalus or mass lesion |
+| (4) CSF opening pressure > 25 cm with normal CSF cytologic and chemical findings |
+| (5) No other causes of ↑ ICP identified |
+| B: Idiopathic IIH Treatment Trial: Modified Dandy Criteria |
+| (1) Signs and symptoms of ↑ ICP |
+| (2) Absence of localized findings in neurologic examination |
+| (3) ↑ CSF pressure > 20 cm; normal neuroimaging except for empty sella, flattening optic nerve head, distention of perioptic subarachnoid space ± tortuous optic nerve, transverse venous sinus stenosis |
+| (4) Awake and alert |
+| (5) No other causes of ↑ ICP |
+| If CSF opening pressure was 20-25 cm, at least 1 of following was also required |
+| Pulse synchronous tinnitus, CNVI palsy, Frisen grade II papilledema, no disc anomalies mimicking disc edema, MRV with lateral sinus collapse/stenosis, partially empty sella, dilated optic nerve sheaths |
+
+
+## Images
+
+
+### Selected Images
+
+![Axial T2 FS MR in a young obese female with headaches and visual symptoms shows flattening of the posterior sclera <img src='/img/arrows/CS.png'/> and minimal protrusion of the optic nerve papilla <img src='/img/arrows/CC.png'/> into the posterior globe. Note mild prominence of the CSF  <img src='/img/arrows/CO.png'/>  along the optic nerve sheaths.](images/app.statdx.com_image_thumbnail_24d4b975-7325-44c1-915b-9a6d28bfe436_annotated_true_size_900_quality_90_3a507534_20251018T164622Z.jpg)
+*Axial T2 FS MR in a young obese female with headaches and visual symptoms shows flattening of the posterior sclera <img src='/img/arrows/CS.png'/> and minimal protrusion of the optic nerve papilla <img src='/img/arrows/CC.png'/> into the posterior globe. Note mild prominence of the CSF  <img src='/img/arrows/CO.png'/>  along the optic nerve sheaths.*
+
+![Axial T2 FS MR in a young obese female with headaches and visual symptoms shows flattening of the posterior sclera <img src='/img/arrows/CS.png'/> and minimal protrusion of the optic nerve papilla <img src='/img/arrows/CC.png'/> into the posterior globe. Note mild prominence of the CSF  <img src='/img/arrows/CO.png'/>  along the optic nerve sheaths.](images/app.statdx.com_image_thumbnail_24d4b975-7325-44c1-915b-9a6d28bfe436_size_174_quality_85_5e6fc32c_20251018T164552Z.jpg)
+*Axial T2 FS MR in a young obese female with headaches and visual symptoms shows flattening of the posterior sclera <img src='/img/arrows/CS.png'/> and minimal protrusion of the optic nerve papilla <img src='/img/arrows/CC.png'/> into the posterior globe. Note mild prominence of the CSF  <img src='/img/arrows/CO.png'/>  along the optic nerve sheaths.*
+
+![Axial DWI in the same patient demonstrates subtle high signal <img src='/img/arrows/CS.png'/> in the region of the optic nerve heads bilaterally. Hyperintensity of the optic nerve heads on DWI can serve as a useful imaging marker for papilledema, especially if bilateral.](images/app.statdx.com_image_thumbnail_ae0e2ddf-eb4d-4442-85d4-ab2b80819b1f_annotated_true_size_900_quality_90_ae9539e6_20251018T164622Z.jpg)
+*Axial DWI in the same patient demonstrates subtle high signal <img src='/img/arrows/CS.png'/> in the region of the optic nerve heads bilaterally. Hyperintensity of the optic nerve heads on DWI can serve as a useful imaging marker for papilledema, especially if bilateral.*
+
+![Axial T1 C+ MR in the same patient shows subtle enhancement <img src='/img/arrows/CC.png'/>, as well as protrusion of prelaminar optic nerves bilaterally.](images/app.statdx.com_image_thumbnail_9a3de7d7-cac0-453f-8762-b1acc1059c51_annotated_true_size_900_quality_90_fbbf5704_20251018T164622Z.jpg)
+*Axial T1 C+ MR in the same patient shows subtle enhancement <img src='/img/arrows/CC.png'/>, as well as protrusion of prelaminar optic nerves bilaterally.*
+
+![Coronal T2 FS MR in the same patient shows a partially empty sella <img src='/img/arrows/CC.png'/> with the pituitary gland <img src='/img/arrows/CS.png'/> flattened along the floor of the sella. Idiopathic intracranial hypertension is more commonly observed in overweight women of reproductive age. Treatment includes weight loss and medications, as well as lumbar punctures, shunt, and optic nerve fenestration.](images/app.statdx.com_image_thumbnail_6033189e-a7cc-4e6f-a8f7-4c3b312359f7_annotated_true_size_900_quality_90_a2d89787_20251018T164622Z.jpg)
+*Coronal T2 FS MR in the same patient shows a partially empty sella <img src='/img/arrows/CC.png'/> with the pituitary gland <img src='/img/arrows/CS.png'/> flattened along the floor of the sella. Idiopathic intracranial hypertension is more commonly observed in overweight women of reproductive age. Treatment includes weight loss and medications, as well as lumbar punctures, shunt, and optic nerve fenestration.*
+
+![Coronal T2 FS MR of orbits in a 6 year old with papilledema and opening CSF pressure of 32 cm of H₂O shows dilated optic nerve sheaths bilaterally <img src='/img/arrows/CC.png'/>.](images/app.statdx.com_image_thumbnail_5e42b718-df6f-41f7-86cd-35fbe1dbee62_annotated_true_size_900_quality_90_29305ac9_20251018T164622Z.jpg)
+*Coronal T2 FS MR of orbits in a 6 year old with papilledema and opening CSF pressure of 32 cm of H₂O shows dilated optic nerve sheaths bilaterally <img src='/img/arrows/CC.png'/>.*
+
+![Sagittal T2 FS MR in the same patient shows tortuosity of the optic nerve, dilated optic nerve sheath <img src='/img/arrows/WS.png'/>, flattening of the posterior sclera <img src='/img/arrows/CC.png'/>, and mild bulging of the optic nerve disc head <img src='/img/arrows/CS.png'/> due to papilledema. Findings are typical of idiopathic intracranial hypertension (IIH). Childhood obesity has a strong association with ↑ risk of pediatric IIH.](images/app.statdx.com_image_thumbnail_2bd694d1-0915-4b68-9b90-85c463dfe179_annotated_true_size_900_quality_90_7a482e85_20251018T164622Z.jpg)
+*Sagittal T2 FS MR in the same patient shows tortuosity of the optic nerve, dilated optic nerve sheath <img src='/img/arrows/WS.png'/>, flattening of the posterior sclera <img src='/img/arrows/CC.png'/>, and mild bulging of the optic nerve disc head <img src='/img/arrows/CS.png'/> due to papilledema. Findings are typical of idiopathic intracranial hypertension (IIH). Childhood obesity has a strong association with ↑ risk of pediatric IIH.*
+
+![Sagittal T2 MR in a young female with IIH and temporal lobe epilepsy shows a defect  <img src='/img/arrows/CS.png'/> along the floor of the middle cranial fossa with herniation of the anteroinferior temporal lobe <img src='/img/arrows/CC.png'/>.](images/app.statdx.com_image_thumbnail_53799f83-fd6b-42ac-b8a4-1041a19ec160_annotated_true_size_900_quality_90_fe5d009a_20251018T164622Z.jpg)
+*Sagittal T2 MR in a young female with IIH and temporal lobe epilepsy shows a defect  <img src='/img/arrows/CS.png'/> along the floor of the middle cranial fossa with herniation of the anteroinferior temporal lobe <img src='/img/arrows/CC.png'/>.*
+
+![Coronal CT cisternogram in a patient with IIH shows an osteodural defect <img src='/img/arrows/CC.png'/> along the great wing of the sphenoid. Defect along the lateral wall of the sphenoid sinus <img src='/img/arrows/CS.png'/> with a meningocele and contrast <img src='/img/arrows/CO.png'/> in the lateral sphenoid sinus due to CSF leak is shown. Patients with IIH can present with spontaneous CSF leaks.](images/app.statdx.com_image_thumbnail_66502da6-e3f7-4a1b-b5de-afe2df76f8d9_annotated_true_size_900_quality_90_ee7dc6dd_20251018T164622Z.jpg)
+*Coronal CT cisternogram in a patient with IIH shows an osteodural defect <img src='/img/arrows/CC.png'/> along the great wing of the sphenoid. Defect along the lateral wall of the sphenoid sinus <img src='/img/arrows/CS.png'/> with a meningocele and contrast <img src='/img/arrows/CO.png'/> in the lateral sphenoid sinus due to CSF leak is shown. Patients with IIH can present with spontaneous CSF leaks.*
+
+![MIP image of a postcontrast MR venogram study in a patient with IIH shows stenosis of the distal transverse sinuses bilaterally <img src='/img/arrows/CS.png'/>, right &gt; left.](images/app.statdx.com_image_thumbnail_610e2c15-7dd5-42a8-9642-3d8fb1089582_annotated_true_size_900_quality_90_6b91fa11_20251018T164622Z.jpg)
+*MIP image of a postcontrast MR venogram study in a patient with IIH shows stenosis of the distal transverse sinuses bilaterally <img src='/img/arrows/CS.png'/>, right &gt; left.*
+
+![3D VRT MR in the same patient shows transverse sinus stenosis <img src='/img/arrows/CC.png'/>, right &gt; left. Phase contrast and postcontrast MR venogram techniques are preferred over TOF-MR venogram to evaluate for transverse sinus stenosis. Stenting of transverse sinus stenosis in patients with IIH is a controversial treatment option.](164ece26-20b8-4cae-b030-9b72efe9a987)
+*3D VRT MR in the same patient shows transverse sinus stenosis <img src='/img/arrows/CC.png'/>, right &gt; left. Phase contrast and postcontrast MR venogram techniques are preferred over TOF-MR venogram to evaluate for transverse sinus stenosis. Stenting of transverse sinus stenosis in patients with IIH is a controversial treatment option.*
+
+
+### Additional Images
+
+![Coronal T1WI MR in the same patient shows unusually small lateral ventricles with a &quot;pinched&quot; appearance. These findings in an obese female with headaches and papilledema are consistent with IIH.](970fd4dc-11be-4478-9403-460a22cd3552)
+*Coronal T1WI MR in the same patient shows unusually small lateral ventricles with a &quot;pinched&quot; appearance. These findings in an obese female with headaches and papilledema are consistent with IIH.*
+
+![Axial T2WI MR shows ↑ fluid in bilateral optic nerve sheaths with mild flattening of the globes at optic nerve insertion. Also note the CSF-filled and expanded empty sella <img src='/img/arrows/BS.png'/>.](3bf70f24-e2cf-411f-afde-5d27b9d05741)
+*Axial T2WI MR shows ↑ fluid in bilateral optic nerve sheaths with mild flattening of the globes at optic nerve insertion. Also note the CSF-filled and expanded empty sella <img src='/img/arrows/BS.png'/>.*
+
+![Sagittal T1WI MR in another patient with IIH (&quot;pseudotumor cerebri&quot;) shows empty sella <img src='/img/arrows/BC.png'/>. The ventricular size is normal.](390c2ec4-5e56-423f-bffb-2414615987cd)
+*Sagittal T1WI MR in another patient with IIH (&quot;pseudotumor cerebri&quot;) shows empty sella <img src='/img/arrows/BC.png'/>. The ventricular size is normal.*
+
+![Axial T2WI MR shows ↑ fluid in the sheaths surrounding the optic nerves <img src='/img/arrows/WC.png'/>, associated with severe scleral flattening <img src='/img/arrows/BO.png'/>.](df25df16-6b53-4850-a23d-304bb0de9fb4)
+*Axial T2WI MR shows ↑ fluid in the sheaths surrounding the optic nerves <img src='/img/arrows/WC.png'/>, associated with severe scleral flattening <img src='/img/arrows/BO.png'/>.*
+
+![Axial T2WI MR shows dilated CSF spaces around the optic nerves <img src='/img/arrows/WO.png'/> and protrusion of the optic nerve papilla into the posterior globes <img src='/img/arrows/WC.png'/>. Opening CSF pressure in this 32-year-old woman was 45 cm of H₂O. Prominent CSF space in the suprasellar cistern represents an empty sella <img src='/img/arrows/WS.png'/>. Note the tortuosity of the left optic nerve.](56e575d8-16f3-4e95-95f8-2d3cbb5caea6)
+*Axial T2WI MR shows dilated CSF spaces around the optic nerves <img src='/img/arrows/WO.png'/> and protrusion of the optic nerve papilla into the posterior globes <img src='/img/arrows/WC.png'/>. Opening CSF pressure in this 32-year-old woman was 45 cm of H₂O. Prominent CSF space in the suprasellar cistern represents an empty sella <img src='/img/arrows/WS.png'/>. Note the tortuosity of the left optic nerve.*
+
+![Sagittal T1WI MR in the same patient shows a partially empty sella <img src='/img/arrows/WS.png'/>, suggesting high CSF pressure in this young obese woman with headaches.](2b283afb-fa49-4301-af75-c08cd47d46e6)
+*Sagittal T1WI MR in the same patient shows a partially empty sella <img src='/img/arrows/WS.png'/>, suggesting high CSF pressure in this young obese woman with headaches.*
+
+![Axial T1WI C+ MR in the same patient demonstrates enhancement, as well as protrusion of prelaminar optic nerves bilaterally <img src='/img/arrows/WC.png'/>. Mild diffuse optic nerve sheath enhancement is also present.](5520270b-2fc2-4233-8468-bb37f0efdc21)
+*Axial T1WI C+ MR in the same patient demonstrates enhancement, as well as protrusion of prelaminar optic nerves bilaterally <img src='/img/arrows/WC.png'/>. Mild diffuse optic nerve sheath enhancement is also present.*
+
+![Coronal T1WI C+ FS MR in the same patient shows diffuse enhancement of the optic nerve sheaths <img src='/img/arrows/WC.png'/> associated with prominent subarachnoid spaces along the optic nerves. Treatment for pseudotumor cerebri includes weight loss and medications, as well as lumbar punctures, shunt, and optic nerve fenestration.](0a5bed97-d570-4eeb-b531-590bbaca6290)
+*Coronal T1WI C+ FS MR in the same patient shows diffuse enhancement of the optic nerve sheaths <img src='/img/arrows/WC.png'/> associated with prominent subarachnoid spaces along the optic nerves. Treatment for pseudotumor cerebri includes weight loss and medications, as well as lumbar punctures, shunt, and optic nerve fenestration.*
+
+![Sagittal T1 MR in a patient with IIH shows a partially empty sella <img src='/img/arrows/CC.png'/> with the pituitary gland <img src='/img/arrows/CS.png'/> flattened along the floor of the sella.](72675faf-c940-4f75-9867-fd6a13d4baca)
+*Sagittal T1 MR in a patient with IIH shows a partially empty sella <img src='/img/arrows/CC.png'/> with the pituitary gland <img src='/img/arrows/CS.png'/> flattened along the floor of the sella.*
+
+![MIP image of a postcontrast MR venogram study in the same patient shows stenosis of the distal transverse sinuses bilaterally <img src='/img/arrows/CS.png'/>. Transverse sinus stenosis is common in patients with IIH.](a5ccfa9c-e717-4afd-9745-28dfcf0d1498)
+*MIP image of a postcontrast MR venogram study in the same patient shows stenosis of the distal transverse sinuses bilaterally <img src='/img/arrows/CS.png'/>. Transverse sinus stenosis is common in patients with IIH.*
+
+![Axial T2WI MR in a young obese female with headaches and visual symptoms shows mild dilatation of the CSF spaces <img src='/img/arrows/CS.png'/> around the optic nerves. There is mild flattening of the posterior sclera <img src='/img/arrows/CC.png'/> and minimal protrusion of the optic nerve papilla <img src='/img/arrows/CO.png'/> into the posterior globe.](84a7ddc8-9ad0-4905-8866-acb2c4b60502)
+*Axial T2WI MR in a young obese female with headaches and visual symptoms shows mild dilatation of the CSF spaces <img src='/img/arrows/CS.png'/> around the optic nerves. There is mild flattening of the posterior sclera <img src='/img/arrows/CC.png'/> and minimal protrusion of the optic nerve papilla <img src='/img/arrows/CO.png'/> into the posterior globe.*
+
+![3D TOF-MR venogram image in the same patient shows stenosis in the distal transverse sinuses bilaterally <img src='/img/arrows/CC.png'/>. Stent placement in sinus stenosis with significant pressure differentials has shown to reduce papilledema.](21466142-7771-4e31-ac8a-4b6fd8d008d5)
+*3D TOF-MR venogram image in the same patient shows stenosis in the distal transverse sinuses bilaterally <img src='/img/arrows/CC.png'/>. Stent placement in sinus stenosis with significant pressure differentials has shown to reduce papilledema.*
+