CONGENITAL LATERAL CEREBRAL VENTRICULOMEGALY FETAL SONOGRAM ASSESMENT FREE LANCE RADIOLOGY CONTINUATION OF EDUCATION IN BASIC DIAGNOSTIC RADIOLOGY
FETAL CEREBRAL LATERAL VENTRICULOMEGALY AN OVERVIEW• Ventriculomegaly : 0.3 to 0.5/ 1000 births .• Frank hydrocephalus is synonymous to overt lateral ventriculomegaly• Ventricles have three dimensional architecture &Variable degree of enlargement is appreciated in different trimesters• Initially assessment was done with – RATIO OF – MIDLINE to LATERAL WALL OF Case of fetal cerebral Lateral THE VENTRICLE MIDLINE TO IPSILATTERAL ventriculomegaly . CALVARIUM Both the lateral ventricles show significant and near symmetrical dilatation.
MILD LATERAL CEREBRAL VENTRICULOMEGALY• Mild lateral cerebral ventriculomegaly ( 10 to 15 mm )• Isolated ventriculomegaly ( No consequence) . It could be earliest manifestation of brain damage .• CNS and NON CNS anomalies may be associated with it . – Primary cerebral maldevelopment ( obstructive hydrocephalus ) – Agyria – Destructive lesions – Periventricular leukomalacia – Hypoxia
MILD LATERAL CEREBRAL VENTRICULOMEGALY• NRA : NEAR CALVARIUM REVERBATION ARTEFACT LIMITS THE SONIC WINDOW HENCE – Transverse diameter of the ventricular atrium is taken at level of glomus of choroid . – Measurement is taken in the axial plane along the atrium distal to transducer . Inside echoes are measured• Values are – Mid trimester ( 6 to 7mm +_ 1mm) . – 14 to 40 wks ( 7mm +_ 1mm) .• Some degree of asymmetry in either side ventricles is noted .• Male fetus have larger measurements than the female ones.
MILD LATERAL CEREBRAL VENTRICULOMEGALY• Mild lateral cerebral ventriculomegaly ( 10 to 15mm inclusive).• If unilateral - benign.• Consider – Fetal MRI – Fetal ECG . – Fetal corpus callosum assessment – Fetal karyotyping. – First trimester screening.• To note : – X linked variety of hydrocephalus develops in lateral gestation.• Caesarean section may have to be opted due to associated macrocrania.• Cephalocentesis /Ventriculoamniotic shunting are also options
OVERT LATERAL CEREBRAL VENTRICULOMEGALY• Overt cerebral lateral ventriculomegaly or hydrocephalus . – Atrial width >15mm – ( 2 to third trimester) . – Associations • Neural tube defects . • Mid line anomalies . • Either aqueductal stenosis / communicating hydrocephalus .• Dangling choroid sign ( choroid away from transducer touches the ventricular wall and one near to the choroid abuts the interventricular septum ) .
MEASURES THEAXIAL IMAGE OF THEVENTRICLE AWAYFROM THETRANSDUCER AT THELEVEL OF GLOMUS OFCHOROID.AVOIDMEASUREMENT OFTHE VENTRICLENEAR TO THETRANSDUCER DUE TONRA : NEARCALVARIUMREVERBATIONARTEFACT UNILATERAL FETAL CEREBRAL VENTRICULOMEGALY.
ASSESEMENT OFCORPUS CALLOSUMSHOULD BE DONE3D / 4D IMAGING ISOF HELP . NORMAL CORPUS CALLOSUM IN CASE OF UNILATERAL VENTRICULOMEGALY ( USUALLY BENIGN)
DANGLING CHOROIDSIGNCHOROID PLEXUS OFTHE VENTRICLEAWAY FROM THETRANSDUCER ABUTSTHE LATERALVENTRICULAR WALLAND OTHER CHOROIDPLEXUS ABUTS THESEPTUM. DANGLING CHOROID SIGN IN CASE OF BILATERAL FETAL VENTRICULOMEGALY
SMALL POSTERIORFOSSADILATED CENTRALCANALPOSSIBLE ARNOLDCHIARIMALFORMATION INCASE OFVENTRICULOMEGALY.FETAL MR CAN BE OFHELP. CNS ANOMALIES ASSOCIATED WITH VENTRICULOMEGALY