CONGENITAL LATERAL CEREBRAL VENTRICULOMEGALY

FETAL SONOGRAM ASSESMENT

FREE LANCE RADIOLOGYCONTINUATION 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 THE VENTRICLE MIDLINE TO IPSILATTERAL CALVARIUM

Case of fetal cerebral Lateral ventriculomegaly .

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 ( 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

MILD 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 ) .

OVERT LATERAL CEREBRAL VENTRICULOMEGALY

UNILATERAL FETAL VENTRICULOMEGALYUSUALLY BENIGN

CONSIDER

FETAL MRI

FETAL ECG

KARYOTYPING

ASSESS FETAL CORPUS CALLOSUM

UNILATERAL FETAL CEREBRAL VENTRICULOMEGALY.

MEASURES THE AXIAL IMAGE OF THE VENTRICLE AWAY FROM THE TRANSDUCER AT THE LEVEL OF GLOMUS OF CHOROID.

AVOID MEASUREMENT OF THE VENTRICLE NEAR TO THE TRANSDUCER DUE TO NRA : NEAR CALVARIUM REVERBATION ARTEFACT

NORMAL CORPUS CALLOSUM IN CASE OF UNILATERAL VENTRICULOMEGALY ( USUALLY BENIGN)

ASSESEMENT OF CORPUS CALLOSUM SHOULD BE DONE

3D / 4D IMAGING IS OF HELP .

DANGLING CHOROID SIGN IN CASE OF BILATERAL FETAL VENTRICULOMEGALY

DANGLING CHOROID SIGN

CHOROID PLEXUS OF THE VENTRICLE AWAY FROM THE TRANSDUCER ABUTS THE LATERAL VENTRICULAR WALL AND OTHER CHOROID PLEXUS ABUTS THE SEPTUM.

CNS ANOMALIES ASSOCIATED WITH VENTRICULOMEGALY

SMALL POSTERIOR FOSSA

DILATED CENTRAL CANAL

POSSIBLE ARNOLD CHIARI MALFORMATION IN CASE OF VENTRICULOMEGALY.

FETAL MR CAN BE OF HELP.