KEY FACTS Imaging Transmantle gray matter (GM) lining clefts Look for dimple in wall of ventricle if cleft is narrow/closed Up to 1/2 of schizencephalies are bilateral When bilateral, 60% are open-lipped on both sides GM lining clefts may appear…
KEY FACTS Terminology Malformation due to abnormality in late neuronal migration and cortical organization Neurons reach cortex but distribute abnormally, forming multiple small, undulating gyri Result is cortex containing multiple small sulci that often appear fused on gross pathology and…
KEY FACTS Terminology Heterotopia (HTP) Arrested/disrupted migration of groups of neurons from periventricular germinal zone (GZ) to cortex Imaging Ectopic nodule or ribbon, isointense with gray matter on every MR sequence Periventricular, subcortical/transcerebral, molecular layer Periventricular HTP located next to…
KEY FACTS Terminology Septooptic dysplasia (SOD) De Morsier syndrome Imaging Absent septum pellucidum, small optic chiasm Optic nerves, pituitary gland, septum pellucidum Coronal imaging shows Flat-roofed ventricles Downward-pointing anterior horns 3 orthogonal planes crucial to identify all findings Absent septum…
KEY FACTS Terminology Dandy-Walker spectrum (DWS) represents broad spectrum of cystic posterior fossa (PF) malformations DWS/complex “Classic” DW malformation (DWM) Hypoplastic vermis with rotation (HVR) Persistent embryonic Blake pouch cyst (BPC) Mega cisterna magna (MCM) Imaging “Classic” DWM Cystic dilatation…
KEY FACTS Terminology Intracranial lipoma (ICL) Mass of mature adipose tissue (congenital malformation, not true neoplasm) Imaging Well-delineated lobulated extraaxial mass with fat attenuation/intensity CT: -50 to -100 Hounsfield units (HU) (fat density); Ca++ varies from none to extensive MR:…
KEY FACTS Terminology Partial or complete absence of corpus callosum (CC), hippocampal commissure, or anterior commissure (AC); can be isolated or associated with additional cerebral malformations Spectrum of congenital CC structural abnormalities Total agenesis (absence from birth of all anatomically…
KEY FACTS Terminology Complex hindbrain malformation Virtually 100% associated with neural tube closure defect, usually lumbar myelomeningocele (MMC) Imaging Crowded posterior fossa, widened tentorial incisura, tectal beaking, inferior vermian displacement Cascade or waterfall of cerebellum/brainstem downward Uvula/nodulus/pyramid of vermis →…
KEY FACTS Terminology Chiari 1 malformation (CM1): Constellation of findings (not disease, not simply measurement) No clear consensus definition of what constitutes CM1 Traditional: Elongated, peg-shaped cerebellar tonsils extend below foramen magnum (FM) into upper cervical spinal canal 5-mm criterion…
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