Title: By: Nour-Eldin Mohammed
1ByNour-Eldin Mohammed
Neuroradiology Congenital Malformation of CNS
2Callosal Dysgenesis
- Definitions
- 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 ventricles
- Coronal "Trident" anterior horns resemble
"viking helmet" or "moose head - Location Midline anomaly
- Size CC remnants vary in size, shape , Remnant
may be paper thin or bulbous
4Callosal Dysgenesis
Radially arrayed gyri "point to" 3rd ventricle
Absent Cingulate Gyrus
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
- Callosum
- trident shaped lateral ventricles
- vertical hippocampi (open arrow),
- enlarged, "keyhole" shaped
- temporal horns and Probst
- bundles (curved arrow).
7Callosal Dysgenesis
Axial 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 Dysgenesis
- Coronal T2WI MR in fetus shows trident shaped
lateral - ventricles, agenesis of Cc
- "Probst bundle" (curved arrow)
- vertical hippocampus (arrow).
9 Differential Diagnosis of Callosal Dysgenesis
Partial Absence of Callosal Dysgenesis
10 Differential Diagnosis of Callosal Dysgenesis
Destruction of CC
Surgery (callosotomy),trauma
(Acquired interhemispheric disconnection
syndrome) Hypoxic ischemic encephalopathy
(HIE), infarcts Metabolic
11 Differential 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
true - neoplasm
13Lipoma
- General Features
- Best diagnostic clue Well-delineated lobulated
extra-axial mass with fat attenuation/intensity - Location Midline location common
- 80 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.
15Lipoma
Sagittal 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)
16Vielen Dank