Presentation on theme: "By: Nour-Eldin Mohammed"— Presentation transcript:
1By: Nour-Eldin Mohammed NeuroradiologyCongenital Malformation of CNS
2Callosal DysgenesisDefinitions: One or all segments of CC absent (if partial, body remains)CC segments front to back:Lamina rostralis (unmyelinated)• Rostrum (myelinated)Genu• Body• Splenium
3Callosal Dysgenesis General Features: Axial: Parallel lateral ventriclesCoronal: "Trident" anterior horns resemble "viking helmet" or "moose head“Location: Midline anomalySize: CC remnants vary in size, shape , Remnant may be paper thin or bulbous
5Callosal Dysgenesis Lateral ventricles are key to diagnosis: • Parallel (non-converging)• Widely separated• Occipital horns often dilated (colpocephaly)• Pointed frontal horns
6Callosal Dysgenesis Coronal T2WI MR shows agenesis of the corpus Callosumtrident shaped lateral ventriclesvertical hippocampi (open arrow),enlarged, "keyhole" shapedtemporal horns and Probstbundles (curved arrow).
7Callosal DysgenesisAxial NECT with widened "windows" shows colpocephaly, calcified (arrow) midline lipoma that extends through choroid fissures into lateral ventricles (open arrows).Axial TlWI MR shows parallel ventricles, colpocephaly, and a midline lipoma. Note lipoma (arrow) protruding into the lateral ventricles.
8Callosal DysgenesisCoronal T2WI MR in fetus shows trident shaped lateralventricles, agenesis of Cc"Probst bundle" (curved arrow)vertical hippocampus (arrow).
9Differential Diagnosis of Callosal Dysgenesis Partial Absence of Callosal Dysgenesis
10Differential Diagnosis of Callosal Dysgenesis Destruction of CC• Surgery (callosotomy),trauma (Acquired interhemispheric disconnection syndrome)• Hypoxic ischemic encephalopathy (HIE), infarcts• Metabolic
11Differential Diagnosis of Callosal Dysgenesis Stretched Corpus Callosum (e.g.: Hydrocephalus)• Thinned CC but all parts present• Severe hydrocephalus often present
12Lipoma Definitions • Mass of mature non-neoplastic adipose tissue CNS lipomas are congenital malformations, not trueneoplasm
13Lipoma General Features • Best diagnostic clue: Well-delineated lobulated extra-axial mass with fat attenuation/intensity• Location : Midline location common80% supratentorial :40-50% interhemispheric fissure (over corpus callosum; may extend into lateral ventricles, choroid plexus)15-20% suprasellar (attached to infundibulum, hypothalamus)10-15% pineal region (usually attached to tectum)20% infratentorial• Cerebellopontine angle (may extend into lAC, vestibule)• Uncommon: Jugular foramen, foramen magnum
14Lipoma Sagittal Tl WI MR Sagittal Tl WI MR with fat-saturation (a small interhemispheric lipoma (arrows) above the corpus callosum, found incidentally at MR imaging in this patient with headache.
15LipomaSagittal TlWI MR shows a well-circumscribed high signal lesion in the pineal region (arrow).The patient was asymptomatic.Axial gross pathology shows a quadrigeminal lipoma (arrow)