Symposium: OB/GY US (Room B) CNS Anomalies

Transcription

1 82 Symposium: OB/GY US (Room B) 11 : : 10 CNS Anomalies Brain area Midline structure S u p r a t e n t o r i a l ventricular system Cerebral hemisphere Posterior fossa Head size and shape Image plane Tr a n s t h a l a m i c Tr a n s c e r e b e l l a r Tr a n s t h a l a m i c Tr a n s ve n t r i c u l a r Tr a n s t h a l a m i c Tr a n s ve n t r i c u l a r Tr a n s c e r e b e l l a r Transthalamic Landmarks to check for normality C avum septum pellucidum Third ve n t r i c l e Paired thalami Sylvian fissure Anomalies to detect, or exc l u d e, on this view Midline development abnormalities Agenesis of the corpus callosum H o l o p r o s e n c e p h a l y Midline cystic abnormalities(arachnoid cysts, vein of Galen aneurysm)

2 83 Ventricular enlargement involving the third ve n t r i c l e Gross abnormality of the cerebral hemispheres Focal abnormality of the cerebral hemispheres Landmarks to check for normality Ventricular atrium Symmetry of the cerebral hemispheres Anomalies to detect, or exc l u d e, on this view All those associated with ve n t r i c u l o m e g a l y Neural tube defects H o l o p r o s e n c e p h a l y Agenesis of the corpus callosum H ydrocephalus of all etiology Po r e n c e p h a l y Tumors Landmarks to check for normality Cisterna magna Cerebellar ve r m i s Cerebellar hemispheres Fourth ve n t r i c l e Anomalies to detect, or exc l u d e, on this view Arnold-Chiari type 2 malformation Cerebellar vermian dysgenesis D a n d y - Wa l ker complex Mega cisterna magna Aneurysm of the vein of Galen Midline arachnoid cysts

3 84 (1) look at the whole of the brain structure (2) search for any associated abnormalities in other body system (3) consider offering a ka r yo t y p e (4) establish the exact diagnosis either following delivery or termination (1) Abnormalities of the midline structure(transthalamic, transcerebellar view ) - Agenesis of the corpus callosum - Holoprosencephaly - Arachnoid cyst - Aneurysm of the vein of Galen - Inferior vermian dysgenesis (2) Supratentorial ventricular system(transthalamic, transventricular view ) - Isolated ve n t r i c u l o m e g a l y - Holoprosencephaly, agenesis of the corpus callosum - Neural tube defects including anencephaly (3) Cerebral mentle(transthalamic, transventricular view ) - Anencephaly and acrania - Holoprosencephaly - Infection - Bleed and porencephaly - Lissencephaly and schizencephaly - Tu m o r (4) Posterior fossa (transcerebellar view ) - Arnold-Chiari malformation - Mega cisterna magna - Inferior vermian dysgenesis - Cerebellar hy p o p l a s i a (5) Head size and shape (transthalamic, transve n t r i c u l a r, transcerebellar view ) - Micro-, and macrocephaly

4 85 - Brachyc e p h a l y - Dolicocephaly - Clover-leaf and strawberry-shaped skull - Colpocephaly(focal dilatation of the posterior horns of the lateral ve n t r i c l e s ) - absent cavum septum pellucidum Associated anomalies - Holoprosencephaly - midline arachnoid cyst - neuronal migration disorders- lissencephaly - Dandy-Wa l ker complex - Arnold-Chiari 2 malformation - encephalocele - Absence of the skull vault and skin cove r i n g - frog eye appearance of fetal face - failure of normal development of the cerebral h e m i s p h e r e - disorganizing of brain tissue that is present - widening of the upper cervical spine - 4:1 female to male predominance - raised maternal serum alphafetoprotein

5 86 - Cyst at the supratentorially in the midline - turbulent blood flow within the enlarged venous side - cardiomegaly (high output cardiac failure) - hepatic venous congestion - hyd r o p s Characteristic finding - avascular cyst - mc posterior end of the third ve n t r i c l e - supratentorial within the interhemispheric fissure - posterior to the cerebellar vermis in the posterior fossa Differential diagnosis - aneurysm of the vein of Galen P r o g n o s i s - dependent on size, rate of growth, location - chromosomal anomalies (T. 18 ) - associated anomalies (ACC, hyd r o c e p h a l u s ) Clinical significant - if isolated : physiologic process (resolve within 26 wks) - chromosomal anomalies : T.18, T.21, triploidy

6 87 Symptoms found in survivo r s - separation of the cerebellar hemisphere - developmental delay (absent ve r m i s ) - motor delay - large cyst in posterior fossa - seizure - variable degree of ve n t r i c u l o m e g a l y - hyd r o c e p h a l u s Associated CNS anomalies - holoprosencephaly - agenesis of the corpus callosum - occipital encephalocele - neuronal migration disorders Differential diagnosis - defect in the skull and dura - cystic hygroma - mc in the midline, occipital(85%) - parietal(12%) Associated anomalies - frontal - microcephaly - agenesis of corpus callosum - Arnold-Chiari malformation - Lemon-shaped skull - microcephaly and brachyc e p h a l y - absent cavum septum pellucidum - fused thalami

7 88 - monove n t r i c l e - incomplete cerebral mentle - facial abnormalities(cleft lip and palate, proboscis, hypotelorism, cebocephaly) Type: alobar, semilobar, lobar Chromosomal anomalies: T. 13 Risk factors - family history - diet : deficiency of folate supplements - teratogens : carbamazepine, sodium va l p r o a t e, warfarin, lithium - DM mother - lemon sign(scalloped frontal bone) - banana sign(descent cerebellar hemisphere, effaced cisterna magna) - microcephaly - spina bifida - skin disruption with protruding sac - club feet - elevated serum alphafetoprotein - Infection - Hemorrhage - Tu m o r - Po r e n c e p h a l y, schizencephaly - Lissencephaly - Iniencephaly - Cerebellar hy p o p l a s i a - Mega cisterna magna