Files
statdx/docs_md/articles/csf-like-parenchymal-lesions_24559f7a-ed5a-4ab6-90ba-769f0b5c1197.md
2025-10-20 21:15:33 +01:00

51 KiB

title, docid, authors, breadcrumbs, category, documentVersionId, imageCount, lastUpdated, pageDescription, pageKeywords, pageTitle, enhancedTitle, type, references, breadcrumbs
title docid authors breadcrumbs category documentVersionId imageCount lastUpdated pageDescription pageKeywords pageTitle enhancedTitle type references breadcrumbs
CSF-Like Parenchymal Lesion(s) 24559f7a-ed5a-4ab6-90ba-769f0b5c1197
key value
4b6589b0-9b8d-4467-8a90-01a0a59742fc Troy A. Hutchins, MD
key value
5cff4116-3654-4b3a-bb75-5ebe0b8c9850 Anne G. Osborn, MD, FACR
name slug treeNodeId
Brain brain 6d8829f1-14d7-45af-8675-255189aa526a
name slug treeNodeId
Differential Diagnosis differential-diagnosis a7fdd139-664e-4bb8-8d18-400e4733ff60
name slug treeNodeId
Brain Parenchyma, General brain-parenchyma-general e79be97b-28c0-4023-be87-334c0579d35d
name slug treeNodeId
Generic Imaging Patterns generic-imaging-patterns 66ab9cf6-74ad-42b7-a40a-4b6224edaa25
name slug treeNodeId
CSF-Like Parenchymal Lesion(s) csf-like-parenchymal-lesions null
Brain 5368df09-e002-41e2-8b4e-fbc71286b47d 51 01/18/23 CSF-Like Parenchymal Lesion(s) Brain, Differential Diagnosis, Brain Parenchyma, General, Generic Imaging Patterns, CSF-Like Parenchymal Lesion(s) CSF-Like Parenchymal Lesion(s) | STATdx CSF-Like Parenchymal Lesion(s) DDX true
Brain
Differential Diagnosis
Brain Parenchyma, General
Generic Imaging Patterns
CSF-Like Parenchymal Lesion(s)

title: "CSF-Like Parenchymal Lesion(s)" docid: "24559f7a-ed5a-4ab6-90ba-769f0b5c1197" authors:

  • key: "4b6589b0-9b8d-4467-8a90-01a0a59742fc" value: "Troy A. Hutchins, MD"
  • key: "5cff4116-3654-4b3a-bb75-5ebe0b8c9850" value: "Anne G. Osborn, MD, FACR" breadcrumbs:
  • name: "Brain" slug: "brain" treeNodeId: "6d8829f1-14d7-45af-8675-255189aa526a"
  • name: "Differential Diagnosis" slug: "differential-diagnosis" treeNodeId: "a7fdd139-664e-4bb8-8d18-400e4733ff60"
  • name: "Brain Parenchyma, General" slug: "brain-parenchyma-general" treeNodeId: "e79be97b-28c0-4023-be87-334c0579d35d"
  • name: "Generic Imaging Patterns" slug: "generic-imaging-patterns" treeNodeId: "66ab9cf6-74ad-42b7-a40a-4b6224edaa25"
  • name: "CSF-Like Parenchymal Lesion(s)" slug: "csf-like-parenchymal-lesions" treeNodeId: null category: "Brain" documentVersionId: "5368df09-e002-41e2-8b4e-fbc71286b47d" imageCount: 51 lastUpdated: "01/18/23" pageDescription: "CSF-Like Parenchymal Lesion(s)" pageKeywords: "Brain, Differential Diagnosis, Brain Parenchyma, General, Generic Imaging Patterns, CSF-Like Parenchymal Lesion(s)" pageTitle: "CSF-Like Parenchymal Lesion(s) | STATdx" enhancedTitle: "CSF-Like Parenchymal Lesion(s)" type: "DDX" references: true breadcrumbs:
  • "Brain"
  • "Differential Diagnosis"
  • "Brain Parenchyma, General"
  • "Generic Imaging Patterns"
  • "CSF-Like Parenchymal Lesion(s)"

ESSENTIAL INFORMATION

  • Key Differential Diagnosis Issues

    • Key imaging questions - Does lesion follow CSF on all modalities/sequences? - Is there any associated mass effect? - Does lesion enhance?
    • Included - CSF-like cystic mass(es), e.g., enlarged perivascular spaces (PVS), neuroglial cysts
    • Excluded - Cystic neoplasms, abscess, resolving hematoma (rarely exactly like CSF) - Developmental cysts that do not behave exactly like CSF (e.g., epidermoid, neurenteric cysts)
  • Helpful Clues for Common Diagnoses

    • Enlarged Perivascular Spaces - PVS - Can be seen at all ages but ↑ with age - Filled with interstitial fluid but follow CSF on all sequences - Most have no abnormality in surrounding parenchyma on FLAIR - ~ 25% have thin, hyperintense rim - Bilateral > unilateral - Multiple > solitary - "Clusters" of variably sized, CSF-like cysts characteristic - Can occur anywhere but most common locations = basal ganglia (BG), hemispheric white matter (WM), midbrain, dentate nuclei - Variant (mostly in older adults) = "état criblé" ("cribriform state") with multiple tiny cysts in BG - Classification - Type I: BG - Type II: High convexity WM - Type III: Midbrain - Large PVS cause mass effect, assume bizarre configurations, and can mimic cystic neoplasm
    • Encephalomalacia - Etiology varies (trauma, infarction, etc.) - Can be solitary, multifocal, multicystic - CSF-like ± adjacent FLAIR hyperintensity
    • Lacunar Infarction - Solitary or multiple - Typically along single long, unpaired penetrating arteries &/or vascular watershed zones - BG, thalamus, WM common - Multifocal BG infarcts + surrounding gliosis = "état lacunaire" or "lacunar state"
    • Neurocysticercosis - Most neurocysticercosis (NCC) cysts are actually in sulci - Cysts in vesicular stage smooth, thin walled, with scolex generally visible as "dot" within cyst - Multiple lesions in mixed stages common - Some enhance, some do not - Ca⁺⁺ (multiple = starry-sky pattern)
  • Helpful Clues for Less Common Diagnoses

    • Porencephalic Cyst - CSF-filled parenchymal cavity - Communicates with ventricle &/or pial surface - Lined by reactive gliosis/astrocytic proliferation - Does not enhance - Etiology varies (trauma, infarction, etc.)
    • Multiple Sclerosis - Chronic "burned-out" lesions - Appear as CSF foci with hyperintense rinds on FLAIR - Look for faint T1 hyperintensity surrounding lesions ("lesion within lesion") - Obtain sagittal FLAIR to look for other lesions along callososeptal interface
    • Hippocampal Sulcus Remnants - "String of beads" cysts medial to temporal horns of lateral ventricles - Developmental variant, incidental - Remnants of vestigial primary embryonic hippocampal sulcus - Imaging - Between hippocampus, dentate gyrus - Follow CSF on all sequences - No surrounding gliosis
    • Connatal Cysts - Single or multiple - Location - Intra- or periventricular (may actually be cysts of anterior choroid plexus) - Small cyst adjacent to tip of frontal horn may be normal anatomic variant - Lined with ependyma - Present at birth - Usually transient - Occasionally seen in older patients - No septations, no hemosiderin - Generally isolated without associated abnormalities
  • Helpful Clues for Rare Diagnoses

    • Neuroglial Cyst - Benign, glial-lined, nonenhancing CSF-like cyst - No surrounding signal abnormality - Does not communicate with ventricle - Subcortical WM, choroidal fissure common sites - Does not restrict on DWI - No enhancement
    • Cryptococcosis - Opportunistic fungal infection - Nonenhancing, gelatinous pseudocysts in PVS - BG, thalamus, brainstem, cerebellum, dentate nucleus, periventricular WM - Multifocal > > solitary lesions - Most patients have HIV/AIDS
    • Parasites, Miscellaneous - Other than NCC, parasitic brain cysts uncommon - Hydatid cyst - Unilocular cyst, isointense to CSF - T2-hypointense rim, no enhancement
    • Mucopolysaccharidoses - Group of lysosomal storage disorders - PVS dilated by accumulated glycosaminoglycans - Corpus callosum, peritrigonal WM - Multiple, bilateral - Dilated PVS in deep periventricular WM - FLAIR-hyperintense rim surrounding dilated PVS
    • Germinolytic Cysts - Periventricular/subependymal cysts - Cyst(s) along caudothalamic groove probably resulting from germinolysis - Glial (not ependymal)-lined cysts/pseudocysts - Distinguish from "connatal" cysts (intraventricular anterior choroid plexus cysts) - Many etiologies, including inherited metabolic disorders (e.g., Zellweger, infantile Refsum), congenital infections (CMV) - CSF-like; ± septations, hemosiderin; do not enhance - Look for associated abnormalities - Leukoencephalopathy - Delayed myelination - Polymicrogyria, pachygyria, heterotopias
    • Miscellaneous Congenital Malformations - Several have parenchymal CSF-like cysts as part of syndrome - van der Knaap leukoencephalopathies (megaloencephalic leukoencephalopathy with subcortical cysts, anterior temporal lobe cavitations) - Congenital muscular dystrophy (cerebellar cysts common, may represent dilated PVS) - Dorsal interhemispheric CSF cyst - Corpus callosal dysgenesis - Holoprosencephaly
  • Alternative Differential Approaches

    • Based on location - Deep gray nuclei - Enlarged PVS - Lacunar infarction - Cryptococcosis - Periventricular WM - Multiple sclerosis - Connatal cysts - Germinolytic cysts - Lobar - Encephalomalacia - NCC - Porencephalic cyst - Neuroglial cyst - Hydatid cyst

References

Selected References

  1. Filippi M et al: Present and future of the diagnostic work-up of multiple sclerosis: the imaging perspective. J Neurol. ePub, 2022
  2. Gyanwali B et al: Arterial spin-labeling parameters and their associations with risk factors, cerebral small-vessel disease, and etiologic subtypes of cognitive impairment and dementia. AJNR Am J Neuroradiol. 43(10):1418-23, 2022
  3. Kim HG et al: MRI-visible dilated perivascular space in the brain by age: the human connectome project. Radiology. 213254, 2022
  4. Loh DDL et al: Tumefactive perivascular spaces causing obstructive hydrocephalus. Radiology. 221724, 2022
  5. Roosendaal SD et al: Imaging patterns characterizing mitochondrial leukodystrophies. AJNR Am J Neuroradiol. 42(7):1334-40, 2021
  6. Ajtai B et al: Imaging of intracranial cysts. Continuum (Minneap Minn). 22(5, Neuroimaging):1553-73, 2016
  7. Taillibert S et al: Intracranial cystic lesions: a review. Curr Neurol Neurosci Rep. 14(9):481, 2014
  8. Osborn AG, Preece MT. Intracranial cysts: radiologic-pathologic correlation and imaging approach. Radiology. 239(3):650-64, 2006
  9. Salzman KL et al: Giant tumefactive perivascular spaces. AJNR Am J Neuroradiol. 26:298-305, 2005

Images

Selected Images

Axial T2 MR shows a cluster of CSF-like cysts in the inferior left basal ganglia , a common location for enlarged perivascular spaces. They are often seen at the level of the anterior commissure. Enlarged Perivascular Spaces Axial T2 MR shows a cluster of CSF-like cysts in the inferior left basal ganglia , a common location for enlarged perivascular spaces. They are often seen at the level of the anterior commissure.

Axial T2 MR shows a cluster of CSF-like cysts in the inferior left basal ganglia , a common location for enlarged perivascular spaces. They are often seen at the level of the anterior commissure. Enlarged Perivascular Spaces Axial T2 MR shows a cluster of CSF-like cysts in the inferior left basal ganglia , a common location for enlarged perivascular spaces. They are often seen at the level of the anterior commissure.

Axial T2 MR shows a cluster of CSF-like cysts in the inferior left basal ganglia , a common location for enlarged perivascular spaces. They are often seen at the level of the anterior commissure. Enlarged Perivascular Spaces Axial T2 MR shows a cluster of CSF-like cysts in the inferior left basal ganglia , a common location for enlarged perivascular spaces. They are often seen at the level of the anterior commissure.

Axial T2 MR shows a cluster of CSF-like cysts in the inferior left basal ganglia , a common location for enlarged perivascular spaces. They are often seen at the level of the anterior commissure. Enlarged Perivascular Spaces Axial T2 MR shows a cluster of CSF-like cysts in the inferior left basal ganglia , a common location for enlarged perivascular spaces. They are often seen at the level of the anterior commissure.

Axial T2 MR shows a cluster of CSF-like cysts in the inferior left basal ganglia , a common location for enlarged perivascular spaces. They are often seen at the level of the anterior commissure. Enlarged Perivascular Spaces Axial T2 MR shows a cluster of CSF-like cysts in the inferior left basal ganglia , a common location for enlarged perivascular spaces. They are often seen at the level of the anterior commissure.

Axial T2 MR shows a cluster of CSF-like cysts in the inferior left basal ganglia , a common location for enlarged perivascular spaces. They are often seen at the level of the anterior commissure. Enlarged Perivascular Spaces Axial T2 MR shows a cluster of CSF-like cysts in the inferior left basal ganglia , a common location for enlarged perivascular spaces. They are often seen at the level of the anterior commissure.

Axial FLAIR MR in the same patient demonstrates complete suppression of central T2 signal . While most enlarged perivascular spaces have normal signal in the adjacent parenchyma, 25% have thin,  FLAIR-hyperintense rim. These lesions are typically incidental but may be enlarged in certain conditions. Enlarged Perivascular Spaces Axial FLAIR MR in the same patient demonstrates complete suppression of central T2 signal . While most enlarged perivascular spaces have normal signal in the adjacent parenchyma, 25% have thin, FLAIR-hyperintense rim. These lesions are typically incidental but may be enlarged in certain conditions.

Coronal T1 C+ MR shows a nonenhancing, multiloculated cystic structure  in left midbrain, thalamus, and medial temporal lobe, which followed CSF signal on all pulse sequences, consistent with giant tumefactive perivascular space. Mass effect results in hydrocephalus . Enlarged Perivascular Spaces Coronal T1 C+ MR shows a nonenhancing, multiloculated cystic structure in left midbrain, thalamus, and medial temporal lobe, which followed CSF signal on all pulse sequences, consistent with giant tumefactive perivascular space. Mass effect results in hydrocephalus .

Axial FLAIR MR in a newborn shows large,  fairly symmetric cystic areas of encephalomalacia  in both cerebral hemispheres with associated volume loss. Cystic encephalomalacia was a result of hypoxic-ischemic encephalopathy at birth. Encephalomalacia Axial FLAIR MR in a newborn shows large, fairly symmetric cystic areas of encephalomalacia in both cerebral hemispheres with associated volume loss. Cystic encephalomalacia was a result of hypoxic-ischemic encephalopathy at birth.

Axial FLAIR MR in a newborn shows large,  fairly symmetric cystic areas of encephalomalacia  in both cerebral hemispheres with associated volume loss. Cystic encephalomalacia was a result of hypoxic-ischemic encephalopathy at birth. Encephalomalacia Axial FLAIR MR in a newborn shows large, fairly symmetric cystic areas of encephalomalacia in both cerebral hemispheres with associated volume loss. Cystic encephalomalacia was a result of hypoxic-ischemic encephalopathy at birth.

Axial FLAIR MR in a newborn shows large,  fairly symmetric cystic areas of encephalomalacia  in both cerebral hemispheres with associated volume loss. Cystic encephalomalacia was a result of hypoxic-ischemic encephalopathy at birth. Encephalomalacia Axial FLAIR MR in a newborn shows large, fairly symmetric cystic areas of encephalomalacia in both cerebral hemispheres with associated volume loss. Cystic encephalomalacia was a result of hypoxic-ischemic encephalopathy at birth.

Axial T2 3D SPACE MR demonstrates subtotal right middle cerebral artery   and left posterior cerebral artery   encephalomalacia from chronic central embolic infarcts in this patient with atrial fibrillation. Encephalomalacia Axial T2 3D SPACE MR demonstrates subtotal right middle cerebral artery and left posterior cerebral artery encephalomalacia from chronic central embolic infarcts in this patient with atrial fibrillation.

Axial T2 MR shows multiple T2-hyperintense lesions in the periventricular white matter  and thalami  due to remote lacunar infarcts. Lacunar infarcts in the deep gray nuclei are classically seen in patients with vascular dementia. Lacunar Infarction Axial T2 MR shows multiple T2-hyperintense lesions in the periventricular white matter and thalami due to remote lacunar infarcts. Lacunar infarcts in the deep gray nuclei are classically seen in patients with vascular dementia.

Axial T2 MR shows multiple T2-hyperintense lesions in the periventricular white matter  and thalami  due to remote lacunar infarcts. Lacunar infarcts in the deep gray nuclei are classically seen in patients with vascular dementia. Lacunar Infarction Axial T2 MR shows multiple T2-hyperintense lesions in the periventricular white matter and thalami due to remote lacunar infarcts. Lacunar infarcts in the deep gray nuclei are classically seen in patients with vascular dementia.

Axial T2 MR shows multiple T2-hyperintense lesions in the periventricular white matter  and thalami  due to remote lacunar infarcts. Lacunar infarcts in the deep gray nuclei are classically seen in patients with vascular dementia. Lacunar Infarction Axial T2 MR shows multiple T2-hyperintense lesions in the periventricular white matter and thalami due to remote lacunar infarcts. Lacunar infarcts in the deep gray nuclei are classically seen in patients with vascular dementia.

Axial FLAIR MR shows cystic lesions  in the right frontal and left parietal lobes. An eccentric nodule (scolex)    seen in the right frontal lesion on this image helps make the diagnosis of neurocysticercosis. Neurocysticercosis Axial FLAIR MR shows cystic lesions in the right frontal and left parietal lobes. An eccentric nodule (scolex) seen in the right frontal lesion on this image helps make the diagnosis of neurocysticercosis.

Axial FLAIR MR shows cystic lesions  in the right frontal and left parietal lobes. An eccentric nodule (scolex)    seen in the right frontal lesion on this image helps make the diagnosis of neurocysticercosis. Neurocysticercosis Axial FLAIR MR shows cystic lesions in the right frontal and left parietal lobes. An eccentric nodule (scolex) seen in the right frontal lesion on this image helps make the diagnosis of neurocysticercosis.

Axial FLAIR MR shows cystic lesions  in the right frontal and left parietal lobes. An eccentric nodule (scolex)    seen in the right frontal lesion on this image helps make the diagnosis of neurocysticercosis. Neurocysticercosis Axial FLAIR MR shows cystic lesions in the right frontal and left parietal lobes. An eccentric nodule (scolex) seen in the right frontal lesion on this image helps make the diagnosis of neurocysticercosis.

Axial T2 MR reveals multiple cystic lesions in the right inferior frontal region  and the left sylvian fissure  due to racemose neurocysticercosis. Neurocysticercosis Axial T2 MR reveals multiple cystic lesions in the right inferior frontal region and the left sylvian fissure due to racemose neurocysticercosis.

Axial FLAIR MR shows a porencephalic cyst  in the right frontal lobe communicating with the right frontal horn. Porencephalic Cyst Axial FLAIR MR shows a porencephalic cyst in the right frontal lobe communicating with the right frontal horn.

Axial FLAIR MR shows a porencephalic cyst  in the right frontal lobe communicating with the right frontal horn. Porencephalic Cyst Axial FLAIR MR shows a porencephalic cyst in the right frontal lobe communicating with the right frontal horn.

Axial FLAIR MR shows a porencephalic cyst  in the right frontal lobe communicating with the right frontal horn. Porencephalic Cyst Axial FLAIR MR shows a porencephalic cyst in the right frontal lobe communicating with the right frontal horn.

Axial T2 MR demonstrates a classic porencephalic cyst  in the right parietal lobe communicating with the posterior horn of the right lateral ventricle. Porencephalic cysts have CSF signal on all sequences and communicate with the ventricle &/or the pial surface. Porencephalic Cyst Axial T2 MR demonstrates a classic porencephalic cyst in the right parietal lobe communicating with the posterior horn of the right lateral ventricle. Porencephalic cysts have CSF signal on all sequences and communicate with the ventricle &/or the pial surface.

Axial T1 MR in a 34-year-old patient with longstanding, severe multiple sclerosis reveals multiple hypointense foci that are low signal and almost, but not quite, CSF-like. Note the faint, hyperintense rims  that surround some of the MS plaques. The T1 hypointensity correlates with axonal destruction. Multiple Sclerosis Axial T1 MR in a 34-year-old patient with longstanding, severe multiple sclerosis reveals multiple hypointense foci that are low signal and almost, but not quite, CSF-like. Note the faint, hyperintense rims that surround some of the MS plaques. The T1 hypointensity correlates with axonal destruction.

Axial T1 MR in a 34-year-old patient with longstanding, severe multiple sclerosis reveals multiple hypointense foci that are low signal and almost, but not quite, CSF-like. Note the faint, hyperintense rims  that surround some of the MS plaques. The T1 hypointensity correlates with axonal destruction. Multiple Sclerosis Axial T1 MR in a 34-year-old patient with longstanding, severe multiple sclerosis reveals multiple hypointense foci that are low signal and almost, but not quite, CSF-like. Note the faint, hyperintense rims that surround some of the MS plaques. The T1 hypointensity correlates with axonal destruction.

Axial T1 MR in a 34-year-old patient with longstanding, severe multiple sclerosis reveals multiple hypointense foci that are low signal and almost, but not quite, CSF-like. Note the faint, hyperintense rims  that surround some of the MS plaques. The T1 hypointensity correlates with axonal destruction. Multiple Sclerosis Axial T1 MR in a 34-year-old patient with longstanding, severe multiple sclerosis reveals multiple hypointense foci that are low signal and almost, but not quite, CSF-like. Note the faint, hyperintense rims that surround some of the MS plaques. The T1 hypointensity correlates with axonal destruction.

Axial T2 MR in the same patient shows that some lesions have CSF signal intensity . Several others are hyperintense to brain parenchyma   but clearly do not resemble CSF in the lateral ventricles. Multiple Sclerosis Axial T2 MR in the same patient shows that some lesions have CSF signal intensity . Several others are hyperintense to brain parenchyma but clearly do not resemble CSF in the lateral ventricles.

Axial T2 MR shows multiple CSF-like cysts in both hippocampi   just medial to the temporal horns of the lateral ventricles. Hippocampal Sulcus Remnants Axial T2 MR shows multiple CSF-like cysts in both hippocampi just medial to the temporal horns of the lateral ventricles.

Axial T2 MR shows multiple CSF-like cysts in both hippocampi   just medial to the temporal horns of the lateral ventricles. Hippocampal Sulcus Remnants Axial T2 MR shows multiple CSF-like cysts in both hippocampi just medial to the temporal horns of the lateral ventricles.

Axial T2 MR shows multiple CSF-like cysts in both hippocampi   just medial to the temporal horns of the lateral ventricles. Hippocampal Sulcus Remnants Axial T2 MR shows multiple CSF-like cysts in both hippocampi just medial to the temporal horns of the lateral ventricles.

Coronal T2 MR reveals tiny cysts  in the hippocampi bilaterally, classic for hippocampal sulcus remnant cysts, which are incidental findings. Hippocampal Sulcus Remnants Coronal T2 MR reveals tiny cysts in the hippocampi bilaterally, classic for hippocampal sulcus remnant cysts, which are incidental findings.

Coronal ultrasound in a 1-day-old premature infant shows a CSF-like intra- or periventricular cyst  with a tiny strand of tissue    that connects the walls of anterior horn. Connatal Cysts Coronal ultrasound in a 1-day-old premature infant shows a CSF-like intra- or periventricular cyst with a tiny strand of tissue that connects the walls of anterior horn.

Coronal ultrasound in a 1-day-old premature infant shows a CSF-like intra- or periventricular cyst  with a tiny strand of tissue    that connects the walls of anterior horn. Connatal Cysts Coronal ultrasound in a 1-day-old premature infant shows a CSF-like intra- or periventricular cyst with a tiny strand of tissue that connects the walls of anterior horn.

Coronal ultrasound in a 1-day-old premature infant shows a CSF-like intra- or periventricular cyst  with a tiny strand of tissue    that connects the walls of anterior horn. Connatal Cysts Coronal ultrasound in a 1-day-old premature infant shows a CSF-like intra- or periventricular cyst with a tiny strand of tissue that connects the walls of anterior horn.

Axial T2 MR demonstrates connatal cysts surrounded by mild hyperintensity . Whether these are connatal/germinolytic cysts persisting into adulthood or neuroglial cyst is uncertain. Regardless of etiology, such asymptomatic cysts are benign and typically nonprogressive. Connatal Cysts Axial T2 MR demonstrates connatal cysts surrounded by mild hyperintensity . Whether these are connatal/germinolytic cysts persisting into adulthood or neuroglial cyst is uncertain. Regardless of etiology, such asymptomatic cysts are benign and typically nonprogressive.

Axial T2 MR shows a large, well-defined cyst  in the left posterior frontal region. The cyst showed CSF signal on all sequences, which is typical for a neuroglial cyst. Neuroglial Cyst Axial T2 MR shows a large, well-defined cyst in the left posterior frontal region. The cyst showed CSF signal on all sequences, which is typical for a neuroglial cyst.

Axial T2 MR shows a large, well-defined cyst  in the left posterior frontal region. The cyst showed CSF signal on all sequences, which is typical for a neuroglial cyst. Neuroglial Cyst Axial T2 MR shows a large, well-defined cyst in the left posterior frontal region. The cyst showed CSF signal on all sequences, which is typical for a neuroglial cyst.

Axial T1 MR demonstrates a well-defined cyst  in the left choroidal fissure, a typical location for a neuroglial cyst/choroidal fissure cyst. Neuroglial Cyst Axial T1 MR demonstrates a well-defined cyst in the left choroidal fissure, a typical location for a neuroglial cyst/choroidal fissure cyst.

Axial T2 MR in a patient with HIV/AIDS shows several hyperintense cystic areas representing dilated perivascular spaces  from cryptococcosis. Fungi and gelatinous material collect within the spaces. There is typically little to no enhancement following contrast administration. Cryptococcosis Axial T2 MR in a patient with HIV/AIDS shows several hyperintense cystic areas representing dilated perivascular spaces from cryptococcosis. Fungi and gelatinous material collect within the spaces. There is typically little to no enhancement following contrast administration.

Axial T2 MR in a patient with HIV/AIDS shows several hyperintense cystic areas representing dilated perivascular spaces  from cryptococcosis. Fungi and gelatinous material collect within the spaces. There is typically little to no enhancement following contrast administration. Cryptococcosis Axial T2 MR in a patient with HIV/AIDS shows several hyperintense cystic areas representing dilated perivascular spaces from cryptococcosis. Fungi and gelatinous material collect within the spaces. There is typically little to no enhancement following contrast administration.

Axial CECT reveals a unilocular cyst  in the right cerebral hemisphere with no surrounding edema or enhancement, typical of echinococcus (hydatid disease). Parasites, Miscellaneous Axial CECT reveals a unilocular cyst in the right cerebral hemisphere with no surrounding edema or enhancement, typical of echinococcus (hydatid disease).

Axial CECT reveals a unilocular cyst  in the right cerebral hemisphere with no surrounding edema or enhancement, typical of echinococcus (hydatid disease). Parasites, Miscellaneous Axial CECT reveals a unilocular cyst in the right cerebral hemisphere with no surrounding edema or enhancement, typical of echinococcus (hydatid disease).

Axial T1 MR shows multiple enlarged perivascular spaces  in this young child with mucopolysaccharidoses 1H and minimal neurological symptoms. Note severe peritrigonal, callosal involvement. Mucopolysaccharidoses Axial T1 MR shows multiple enlarged perivascular spaces in this young child with mucopolysaccharidoses 1H and minimal neurological symptoms. Note severe peritrigonal, callosal involvement.

Axial FLAIR MR demonstrates 3 findings typical of mucopolysaccharidosis: CSF-like dilated perivascular spaces filled with mucopolysaccharides , hyperintense white matter, and global atrophy. Mucopolysaccharidoses Axial FLAIR MR demonstrates 3 findings typical of mucopolysaccharidosis: CSF-like dilated perivascular spaces filled with mucopolysaccharides , hyperintense white matter, and global atrophy.

Axial T2 MR in an infant with congenital CMV infection shows multiple periventricular germinolytic cysts . Germinolytic Cysts Axial T2 MR in an infant with congenital CMV infection shows multiple periventricular germinolytic cysts .

Coronal FLAIR MR in a patient with infantile Refsum disease reveals bilateral periventricular germinolytic cysts  mimicking Zellweger syndrome. Germinolytic cysts are subependymal along a caudothalamic groove, probably resulting from germinolysis. Germinolytic Cysts Coronal FLAIR MR in a patient with infantile Refsum disease reveals bilateral periventricular germinolytic cysts mimicking Zellweger syndrome. Germinolytic cysts are subependymal along a caudothalamic groove, probably resulting from germinolysis.

Axial T2 MR in a child with congenital muscular dystrophy shows multiple small,  cystic lesions in the dysplastic cerebellum . The pons is hypoplastic with dorsal clefting . Hypomyelination of the temporal lobes  is present. Miscellaneous Congenital Malformations Axial T2 MR in a child with congenital muscular dystrophy shows multiple small, cystic lesions in the dysplastic cerebellum . The pons is hypoplastic with dorsal clefting . Hypomyelination of the temporal lobes is present.

Coronal FLAIR MR in an 18-month-old infant with van der Knaap leukoencephalopathy shows cystic changes in both temporal lobes , characteristic of this condition. Miscellaneous Congenital Malformations Coronal FLAIR MR in an 18-month-old infant with van der Knaap leukoencephalopathy shows cystic changes in both temporal lobes , characteristic of this condition.

Additional Images

Axial T2 MR shows a cluster of CSF-like cysts  in the right frontal subcortical white matter. Enlarged Perivascular Spaces Axial T2 MR shows a cluster of CSF-like cysts in the right frontal subcortical white matter.

Axial FLAIR MR in the same patient shows suppression of the signal  within the cysts. Note subtle FLAIR hyperintensity  surrounding the cysts. Large perivascular spaces can assume a bizarre configuration and mimic a cystic neoplasm. Enlarged Perivascular Spaces Axial FLAIR MR in the same patient shows suppression of the signal within the cysts. Note subtle FLAIR hyperintensity surrounding the cysts. Large perivascular spaces can assume a bizarre configuration and mimic a cystic neoplasm.

Coronal T2 MR shows a cluster of variable-sized CSF-like cysts in left parietal subcortical white matter . Lesions did not enhance. Follow-up scan 5 years later showed no change. Enlarged Perivascular Spaces Coronal T2 MR shows a cluster of variable-sized CSF-like cysts in left parietal subcortical white matter . Lesions did not enhance. Follow-up scan 5 years later showed no change.

Axial T1 MR in a patient with old left internal artery occlusion shows multicystic encephalomalacia. FLAIR, T2-weighted scans showed extensive hyperintensity in the residual parenchyma secondary to gliosis and spongiosis. Encephalomalacia Axial T1 MR in a patient with old left internal artery occlusion shows multicystic encephalomalacia. FLAIR, T2-weighted scans showed extensive hyperintensity in the residual parenchyma secondary to gliosis and spongiosis.

Axial FLAIR MR demonstrates cystic encephalomalacia  in the right frontal lobe due to an old infarct. Note associated volume loss with prominence of the adjacent sulcal spaces. Encephalomalacia Axial FLAIR MR demonstrates cystic encephalomalacia in the right frontal lobe due to an old infarct. Note associated volume loss with prominence of the adjacent sulcal spaces.

Axial T2 MR shows a cystic lesion  in the left caudate nucleus due to an old lacunar infarct. Lacunar infarcts are small, deep cerebral infarcts located in basal ganglia and thalamus, pons, or cerebral white matter, which are ≤ 15 mm in size. Lacunar Infarction Axial T2 MR shows a cystic lesion in the left caudate nucleus due to an old lacunar infarct. Lacunar infarcts are small, deep cerebral infarcts located in basal ganglia and thalamus, pons, or cerebral white matter, which are ≤ 15 mm in size.

Coronal T1 MR in an older adult patient with bilateral subacute subdural hematomas  shows multiple lacunar infarcts  in white matter and basal ganglia. Lacunar Infarction Coronal T1 MR in an older adult patient with bilateral subacute subdural hematomas shows multiple lacunar infarcts in white matter and basal ganglia.

Axial T1 C+ MR shows several nonenhancing CSF-like cysts  of variable sizes in a patient with neurocysticercosis. Several may be cisternal, invaginating into brain. (Courtesy E. Bravo, MD.) Neurocysticercosis Axial T1 C+ MR shows several nonenhancing CSF-like cysts of variable sizes in a patient with neurocysticercosis. Several may be cisternal, invaginating into brain. (Courtesy E. Bravo, MD.)

Axial FLAIR MR shows a cystic lesion  in the left parietal region with an eccentric nodule  and mild perilesional edema  typical of the colloid vesicular stage of neurocysticercosis. Neurocysticercosis Axial FLAIR MR shows a cystic lesion in the left parietal region with an eccentric nodule and mild perilesional edema typical of the colloid vesicular stage of neurocysticercosis.

Sagittal T1 MR shows a variant case of neurocysticercosis with multiple large, well-delineated parenchymal cysts. Neurocysticercosis Sagittal T1 MR shows a variant case of neurocysticercosis with multiple large, well-delineated parenchymal cysts.

Coronal FLAIR MR shows tiny cysts  in the hippocampi bilaterally, classic for hippocampal sulcus remnant cysts. Hippocampal Sulcus Remnants Coronal FLAIR MR shows tiny cysts in the hippocampi bilaterally, classic for hippocampal sulcus remnant cysts.

Axial FLAIR MR shows a classic porencephalic cyst  that suppresses completely on FLAIR. Some gliosis is present, seen here as a faint area of increased signal intensity . Porencephalic Cyst Axial FLAIR MR shows a classic porencephalic cyst that suppresses completely on FLAIR. Some gliosis is present, seen here as a faint area of increased signal intensity .

Axial T1 MR shows fluid replacing a portion of the anteromedial left temporal lobe . The cystic space communicates with the lateral ventricle  and the pial surface of the brain . Porencephalic Cyst Axial T1 MR shows fluid replacing a portion of the anteromedial left temporal lobe . The cystic space communicates with the lateral ventricle and the pial surface of the brain .

Axial T2 MR shows an array of several tiny round and ovoid CSF-like cysts in both hippocampi , just medial to the temporal horns of lateral ventricles. FLAIR scan (not shown) demonstrated that the cysts suppressed completely. Hippocampal Sulcus Remnants Axial T2 MR shows an array of several tiny round and ovoid CSF-like cysts in both hippocampi , just medial to the temporal horns of lateral ventricles. FLAIR scan (not shown) demonstrated that the cysts suppressed completely.

Coronal T2 MR shows a well-defined cyst  in the right choroidal fissure, a typical location for a neuroglial cyst. Neuroglial Cyst Coronal T2 MR shows a well-defined cyst in the right choroidal fissure, a typical location for a neuroglial cyst.

Axial T1 MR in an asymptomatic patient shows a CSF-like cyst  adjacent to, but separated from, the left frontal horn. A smaller cyst present posteriorly . Connatal Cysts Axial T1 MR in an asymptomatic patient shows a CSF-like cyst adjacent to, but separated from, the left frontal horn. A smaller cyst present posteriorly .

Sagittal T2 MR in the same infant shows that the cyst  is definitely CSF-like. Connatal Cysts Sagittal T2 MR in the same infant shows that the cyst is definitely CSF-like.

Sagittal T2 MR shows a variant case of neuroglial cyst  that appears to arise from the tectum, which appears stretched  around the cyst. Neuroglial Cyst Sagittal T2 MR shows a variant case of neuroglial cyst that appears to arise from the tectum, which appears stretched around the cyst.

Axial FLAIR MR shows a large, cystic mass  that suppresses completely but neither enhanced nor restricted. At surgery, the cyst wall was composed of benign glial cells. Neuroglial Cyst Axial FLAIR MR shows a large, cystic mass that suppresses completely but neither enhanced nor restricted. At surgery, the cyst wall was composed of benign glial cells.

Axial FLAIR MR shows a small, subcortical cyst  in the left frontal lobe. The cyst suppresses completely and shows no surrounding gliosis. Neuroglial Cyst Axial FLAIR MR shows a small, subcortical cyst in the left frontal lobe. The cyst suppresses completely and shows no surrounding gliosis.

Coronal T2 MR in a child with infantile Refsum disease shows patchy hyperintensity in cerebellar  and periventricular white matter  as well as the dentate nuclei . Germinolytic Cysts Coronal T2 MR in a child with infantile Refsum disease shows patchy hyperintensity in cerebellar and periventricular white matter as well as the dentate nuclei .

Coronal T2 MR in an infant with Zellweger syndrome shows hypomyelination, multiple small germinolytic cysts , and polymicrogyria . Germinolytic Cysts Coronal T2 MR in an infant with Zellweger syndrome shows hypomyelination, multiple small germinolytic cysts , and polymicrogyria .

Axial T2 MR in an infant with congenital CMV shows hyperintense germinolytic cysts  and extensive perisylvian cortical dysplasia . Unexplained periventricular T2 hyperintensity , periventricular cysts, and neuronal migration and organization abnormalities should suggest congenital CMV infection. Germinolytic Cysts Axial T2 MR in an infant with congenital CMV shows hyperintense germinolytic cysts and extensive perisylvian cortical dysplasia . Unexplained periventricular T2 hyperintensity , periventricular cysts, and neuronal migration and organization abnormalities should suggest congenital CMV infection.

Axial T2 MR in the same patient shows that some lesions show CSF signal intensity . Several others are "bright"  but clearly do not resemble the other lesions or CSF in the lateral ventricles. Multiple Sclerosis Axial T2 MR in the same patient shows that some lesions show CSF signal intensity . Several others are "bright" but clearly do not resemble the other lesions or CSF in the lateral ventricles.

Axial T1 MR in a patient with longstanding multiple sclerosis reveals multiple hypointense foci that are almost (but not quite) CSF-like. Note the faint hyperintense rims  that surround plaques. Multiple Sclerosis Axial T1 MR in a patient with longstanding multiple sclerosis reveals multiple hypointense foci that are almost (but not quite) CSF-like. Note the faint hyperintense rims that surround plaques.