statdx/docs_md/articles/irregular-lateral-ventricles_f42ce651-9877-480b-90d8-665be656b33f.md

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Irregular Lateral Ventricles	f42ce651-9877-480b-90d8-665be656b33f	key value 1fa14dfd-71ea-4960-908e-e720313bc63a Santhosh Gaddikeri, MD key value 30ce27b2-237f-4aff-a88f-65ead356335b Marinos Kontzialis, MD	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 Ventricles, Periventricular Regions ventricles-periventricular-regions 353c434a-a6fc-4ef1-8786-d30a1988a4dc name slug treeNodeId Generic Imaging Patterns generic-imaging-patterns 969c31a2-ef56-4fc3-9125-05857cf9aac3 name slug treeNodeId Irregular Lateral Ventricles irregular-lateral-ventricles null	Brain	2594bf27-49d6-4896-8859-f9eee7b4228c	42	02/15/23	Irregular Lateral Ventricles	Brain, Differential Diagnosis, Ventricles, Periventricular Regions, Generic Imaging Patterns, Irregular Lateral Ventricles	Irregular Lateral Ventricles | STATdx	Irregular Lateral Ventricles	DDX	true	Brain Differential Diagnosis Ventricles, Periventricular Regions Generic Imaging Patterns Irregular Lateral Ventricles

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title: "Irregular Lateral Ventricles" docid: "f42ce651-9877-480b-90d8-665be656b33f" authors:

• key: "1fa14dfd-71ea-4960-908e-e720313bc63a" value: "Santhosh Gaddikeri, MD"
• key: "30ce27b2-237f-4aff-a88f-65ead356335b" value: "Marinos Kontzialis, MD" breadcrumbs:
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• name: "Irregular Lateral Ventricles" slug: "irregular-lateral-ventricles" treeNodeId: null category: "Brain" documentVersionId: "2594bf27-49d6-4896-8859-f9eee7b4228c" imageCount: 42 lastUpdated: "02/15/23" pageDescription: "Irregular Lateral Ventricles" pageKeywords: "Brain, Differential Diagnosis, Ventricles, Periventricular Regions, Generic Imaging Patterns, Irregular Lateral Ventricles" pageTitle: "Irregular Lateral Ventricles | STATdx" enhancedTitle: "Irregular Lateral Ventricles" type: "DDX" references: true breadcrumbs:
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ESSENTIAL INFORMATION

• Key Differential Diagnosis Issues

  • Irregular ventricles may be result of obstruction, chronic volume loss, &/or congenital deformities - Obstruction: Mass effect, ballooned-appearing ventricles, and transependymal CSF migration - Volume loss: Ventricle irregularity with brain parenchymal loss - Congenital: Look for associated findings (colpocephaly, subependymal nodules)
  • Ventricular deformities may become permanent despite relief of obstruction due to parenchymal atrophy or acquired ventricular noncompliance
  • Enhancement may help differentiate etiologies

• Helpful Clues for Common Diagnoses

  • CSF Shunts and Complications - Common complications include shunt obstruction/breakage, infection, overdrainage - Acquired ventricular noncompliance may result in ventricle deformity - Small, "slit" ventricles → noncompliant ventricle syndrome, chronic overdrainage
  • Surgical Defects - Often evident from prior shunt tract or burr hole - Overlying skull or scalp may show defect - Deformity is chronic
  • Periventricular Leukomalacia - Selective vulnerability of periventricular white matter of preterm neonate - Injury in late 2nd or early 3rd trimester - Thinning of posterior body of corpus callosum, enlargement and irregularity of lateral ventricular walls - Colpocephaly: Atrium/occipital horns dilated - Related to spastic cerebral palsy
  • Cerebral Infarction, Chronic - Vascular territory wedge-shaped area of encephalomalacia - Results in compensatory or ex vacuo dilation of regional ventricle due to volume loss
  • Multiple Sclerosis - Multiple periventricular/perivenular and callososeptal T2 hyperintensities - Confluent lesions in severe disease lead to atrophy and irregular ventricular margins
  • Porencephalic Cyst - Congenital porencephalic cysts result from intrauterine vascular or infectious injury - Acquired cysts are secondary to injury later in life from trauma, surgery, ischemia, or infection - CSF intensity cysts with smooth walls and T2-hyperintense surrounding gliotic changes (no gray matter lining walls as in open-lip schizencephaly) - Usually communicate directly with ventricular system

• Helpful Clues for Less Common Diagnoses

  • Chiari 2 - Pointed anterior horns, colpocephaly - Small, crowded posterior fossa, widening of tentorial incisura, towering cerebellum, tectal beaking, downward herniation of cerebellar vermian tissue through foramen magnum - Associated with lumbar myelomeningocele - Hydrocephalus and other midline malformations
  • Heterotopic Gray Matter - Subependymal heterotopia: Subependymal nodules follow gray matter signal and protrude into ventricles; no enhancement - Focal/multifocal asymmetric gray matter indentation of ventricle
  • Tuberous Sclerosis Complex - Subependymal nodules lining ventricles characteristic - Mostly along striothalamic groove - Calcify with increasing age - < 1.3 cm - Cortical and subcortical tubers are usually multifocal ± mild mass effect - Tubers most easily seen on FLAIR - Rarely, tubers may calcify or enhance - White matter radial migration lines - Cyst-like white matter lesions (cystoid brain degeneration) - Enhancing mass with rapid growth at foramen of Monro = subependymal giant cell astrocytoma
  • Metastases, Intracranial, Other - CSF seeding of primary CNS tumors, lymphoma, or systemic malignancy may cause irregular ventricles - Intraventricular metastases = 0.9-4.6% of cerebral metastases - Adults: Renal, colon, lung - Children: Neuroblastoma, Wilms tumor, retinoblastoma - May result in ventricular nodules, which can deform ventricles - Lateral ventricles most common location - Avid enhancement ± vasogenic edema in adjacent parenchyma
  • Intraventricular Webs or Adhesions - May be congenital or acquired (prior hemorrhage, infection, or tumor) - Contours of ventricles may be rounded or balloon-like due to obstructive symptoms - Contrast ventriculography or cine CSF can be helpful to assess for evidence of physiological flow obstruction - Heavily weighted T2 sequences, such as FIESTA/CISS, helpful
  • CMV, Congenital - Microcephaly - Periventricular calcifications 40-70% - Migrational abnormalities: Lissencephaly, pachygyria, polymicrogyria, schizencephaly - Delayed myelination, dysmyelination - Cerebral + cerebellar volume loss - Periventricular cysts, ventriculomegaly, ventricular adhesions, lenticulostriate vasculopathy
  • Schizencephaly - Transmantle cleft lined by gray matter - Open lip (large defect), closed lip (small defect) - Dimple in wall of ventricle when defect small/closed - Up to 50% bilateral - When bilateral, 60% are open lipped on both sides

• Helpful Clues for Rare Diagnoses

  • Hemimegalencephaly - Hamartomatous overgrowth of part/all of hemisphere - Lateral ventricle ipsilateral to enlarged hemisphere is usually bizarre-shaped and typically enlarged - Involved hemisphere may eventually atrophy from chronic seizures
  • Holoprosencephaly - Congenital structural forebrain anomalies defined by degree of frontal lobe fusion - All types have absent septum pellucidum and frontal lobe fusion anomaly - Alobar - Single midline forebrain - Single primitive monoventricle, often incompletely covered posteriorly by brain (dorsal cyst) - Semilobar - Frontal lobes > 50% fused - Thalami and hypothalamus may be fused - Interhemispheric fissure and falx cerebri may be present posteriorly - Facial malformations mild or absent - Lobar: Anterior lateral ventricle may be deficient - Interhemispheric fissure present along most of midline - Only most inferior frontal lobes fused - Thalami almost/completely separated - Callosal dysgenesis (genu, rostrum)
  • Holoprosencephaly Variants - Middle interhemispheric variant of holoprosencephaly - Lack of separation in posterior frontal and parietal areas - Dorsal cyst in 40% - Callosal dysgenesis (body)

• Alternative Differential Approaches

  • Gadolinium studies can differentiate among causes of ependymal nodules
  • Nonenhancing subependymal nodules may represent gray matter heterotopia or tuberous sclerosis nodules - Gray matter heterotopias follow gray matter signal/density - Tuberous sclerosis nodules follow white matter signal or are calcified
  • Enhancing nodules suggest ependymal tumor seeding

References

Selected References

1. Balasubramaniam C: Shunt complications - staying out of trouble. Neurol India. 69(Supplement):S495-501, 2021
2. Society for Maternal-Fetal Medicine (SMFM) et al: Holoprosencephaly. Am J Obstet Gynecol. 223(6):B13-6, 2020
3. Gotardo JW et al: Impact of peri-intraventricular haemorrhage and periventricular leukomalacia in the neurodevelopment of preterms: a systematic review and meta-analysis. PLoS One. 14(10):e0223427, 2019
4. Winter TC et al: Holoprosencephaly: a survey of the entity, with embryology and fetal imaging. Radiographics. 35(1):275-90, 2015
5. Smith AB et al: From the radiologic pathology archives: intraventricular neoplasms: radiologic-pathologic correlation. Radiographics. 33(1):21-43, 2013
6. Osborn AG et al: Intracranial cysts: radiologic-pathologic correlation and imaging approach. Radiology. 239(3):650-64, 2006
7. Melhem ER et al: Periventricular leukomalacia: relationship between lateral ventricular volume on brain MR images and severity of cognitive and motor impairment. Radiology. 214(1):199-204, 2000

Images

Selected Images

CSF Shunts and Complications Axial T2 MR in a patient with chronic shunting demonstrates slit-like irregular lateral ventricles due to noncompliance from chronic drainage.

Surgical Defects Axial FLAIR MR demonstrates a large surgical defect in the left frontal lobe due to prior tumor resection communicating with the left lateral ventricle , which appears irregular.

Periventricular Leukomalacia Axial T2 MR in a 5-year-old boy with spastic cerebral palsy demonstrates irregular lateral ventricles with paucity of white matter and periventricular hyperintensities , consistent with periventricular leukomalacia.

Cerebral Infarction, Chronic Axial T2 MR demonstrates encephalomalacia in the left occipital lobe with ex vacuo dilation of left occipital horn due to PCA territory chronic infarct.

Multiple Sclerosis Axial T2 MR in a patient with primary progressive MS demonstrates extensive white matter hyperintensities with asymmetric parenchymal volume loss and ex vacuo dilation of lateral ventricles .

Porencephalic Cyst Axial T2 MR demonstrates a right occipital lobe, smooth-walled, cystic encephalomalacia lined by white matter and communicating with the lateral ventricle, consistent with porencephalic cyst.

Chiari 2 Axial NECT demonstrates irregular lateral ventricles with a right frontal lobe shunt catheter . Note diffuse calvarial thickening due to chronic shunting. Images of posterior fossa revealed small posterior fossa and other stigmata of Chiari 2 malformation (not shown).

Heterotopic Gray Matter Axial T2 MR demonstrates nodular gray matter heterotopia along the ependymal lining of bilateral occipital horns.

Tuberous Sclerosis Complex Axial 3D T1 MPRAGE in a patient with known tuberous sclerosis demonstrates multiple subependymal nodules . Also note tiny cysts in white matter . Cortical/ subcortical tubers and white matter radial migration lines were seen (not shown).

Metastases, Intracranial, Other Axial T1 C+ MR in a patient with metastatic lung cancer demonstrates multiple heterogeneously enhancing metastatic lesions in bilateral periventricular regions .

Intraventricular Webs or Adhesions Axial 3D T2 HASTE MR in a neonate demonstrates multiple septa/webs in both lateral ventricles . Also note asymmetrically dilated, irregular lateral ventricles . Encephalomalacia in the right parietooccipital region is due to antenatal insult.

CMV, Congenital Axial NECT in a 2-year-old with a known congenital CMV infection demonstrates moderately dilated irregular lateral ventricles as well as periventricular and deep white matter calcifications . Note lissencephalic gyral pattern .

Schizencephaly Axial 3D T1 MR demonstrates open-lip schizencephaly with a seam connecting ependymal to pial surface . Note gray matter lining the cystic area , differentiating it from a porencephalic cyst.

Holoprosencephaly Variants Axial T2 MR demonstrates absent septum with absent posterior body of corpus callosum. Also seen was abnormal bilateral sylvian fissure with ventricle orientation and midline fusion (not shown), consistent with syntelencephaly, a.k.a. middle interhemispheric variant holoprosencephaly.

Additional Images

CSF Shunts and Complications Axial NECT shows a right frontal ventricular drain that traverses the right ventricle but is not decompressing the left lateral ventricle, which remains irregularly enlarged .

Surgical Defects Axial T2 MR shows irregular enlargement of the left occipital horn due to left temporal and occipital surgical defect and encephalomalacia from tumor removal in this location.

Periventricular Leukomalacia Axial T2 MR shows classic "wavy" or undulating contours of the lateral ventricles in addition to colpocephaly (enlargement of the posterior portions of lateral ventricles). Colpocephaly reflects the predominantly posterior volume loss.

Cerebral Infarction, Chronic Axial NECT shows irregular enlargement of the left frontal horn due to focal regional parenchymal volume loss in this patient with remote MCA infarct.

Heterotopic Gray Matter Axial T1 FS MR shows multifocal nodularity along ependymal margins of both lateral ventricles . These nodules follow gray matter signal on all sequences and do not enhance or change over time.

Chiari 2 Axial NECT shows irregularly dilated occipital horns with interdigitation of parietal and occipital parenchyma across midline due to a falx deficiency.

Chiari 2 Coronal T2 MR shows dysgenetic corpus callosum, small posterior fossa, and interdigitation of gyri from deficient falx, best seen post shunting. Cerebellum "towers" through the tentorial notch.

Tuberous Sclerosis Complex Axial T2 MR shows multiple calcified subependymal nodules (SEN) lining ventricles. Note also subcortical tubers . SEN calcify much more commonly than cortical/subcortical tubers. ~ 50% of SEN are calcified by 10 years.

Tuberous Sclerosis Complex Axial T2 MR shows small, subependymal nodules , which indent lateral ventricle margins. Unlike gray matter heterotopia, these follow WM signal or are calcified.

Metastases, Intracranial, Other Axial T1 MR shows nodular ependymal thickening with an enhancing rind of tissue along the entire ventricular ependyma . While infection & primary malignant brain neoplasms such as GBM, germinoma, and lymphoma commonly spread along ventricular ependyma, this is a recognized but uncommon site for tumor deposits from extracranial primary tumors (melanoma in this case).

Schizencephaly Axial T2 MR shows a small dimple on the lateral ventricular wall, which "points" to the site of a fused pial-ependymal seam . The aperture of the cleft is lined by gray matter in this closed-lip schizencephaly.

Schizencephaly Axial T2 MR shows cortical dysplasia and open-lip schizencephaly . Schizencephaly is closed-lip with a fused, gray matter-lined pial-ependymal seam or open-lip with large, gray matter-lined and fluid-filled CSF clefts.

Schizencephaly Axial NECT shows focal outpouchings of CSF from both lateral ventricles with a CSF cleft extending from lateral ventricles to the subpial surface. The pial-ependymal seam is lined by gray matter.

Holoprosencephaly Axial NECT shows septum pellucidum and anterior falx absence. Frontal horns are hypoplastic. A band of parenchyma crosses midline . Mild frontal lobe fusion anomalies, as seen here, are typical of lobar holoprosencephaly.

Schizencephaly Axial T1 MR shows open-lip schizencephaly with large, gray matter-lined and a fluid-filled CSF cleft. In addition, there is ventricular wall irregularity due to subependymal gray matter heterotopia bilaterally .

Schizencephaly Coronal T2 MR demonstrates closed-lip schizencephaly. Abnormal, thick gray matter lines the cleft extending to a dimple in the wall of the right lateral ventricle .

Tuberous Sclerosis Complex Axial CT shows multiple calcified subependymal nodules lining the ventricles in a patient with tuberous sclerosis. The nodules calcify much more commonly than cortical/subcortical tubers. Note traumatic subarachnoid hemorrhage in the left Sylvian fissure.

Heterotopic Gray Matter Axial T2 MR shows multiple bilateral subependymal nodules of heterotopic gray matter along the lateral ventricular margins. These nodules follow gray matter signal on all sequences.

Chiari 2 Axial CT in a Chiari 2 patient shows typical irregular appearance of the ventricles. Note the left posterior shunt catheter .

Cerebral Infarction, Chronic Axial FLAIR MR demonstrates left posterior middle cerebral artery encephalomalacia with mild ex vacuo dilatation of the left occipital horn and atrium .

Periventricular Leukomalacia Axial T2 MR in periventricular leukomalacia shows asymmetric, posterior, periventricular white matter (WM) volume loss with irregular ventricular margins . Periventricular leukomalacia, a.k.a. WM injury of prematurity, is a result of brain injury occurring before 33 weeks gestation and resulting in loss of periventricular WM.

Surgical Defects Axial FIESTA MR in a patient following left temporal bone surgery shows skull defect , underlying encephalomalacia , and ex vacuo dilatation of the left lateral ventricle .

CSF Shunts and Complications Axial T1 MR demonstrates a right parietal shunt catheter with its tip in the right frontal horn in a patient with congenital aqueductal stenosis. The right lateral ventricle is collapsed, while the 3rd and left lateral ventricles are moderately dilated.

Porencephalic Cyst Axial CECT shows a low-density outpouching from the right lateral ventricle . While a thin rim of cortex seems intact, the cyst nearly reaches brain surface and can be considered a porencephalic dilation or porencephalic lateral ventricle cyst.

Metastases, Intracranial, Other Axial T2 MR shows near-complete coating of the ependymal lining of both lateral ventricles with tumor nodules due to metastatic seeding of an anaplastic oligodendroglioma.

CMV, Congenital Axial NECT shows periventricular calcification , particularly along the caudostriatal groove, in the context of microcephaly and developmental delay. This strongly suggests congenital CMV infection. Note smooth ventricular margins, unlike calcified nodules in tuberous sclerosis complex.

Hemimegalencephaly Axial T2 MR shows enlargement of left cerebral hemisphere accompanied by an irregular ipsilateral ventricle . The body of the left hemispheric WM is bulky. Note left fornix overgrowth.

Holoprosencephaly Axial T1 MR shows a large, horseshoe-shaped monoventricle with fused basal ganglia . There is no interhemispheric fissure and no identifiable lobulation or formation of ventricular horns in this alobar holoprosencephaly.