Winning Abstracts from the 2010 Medical Student Abstract Competition: Ultrasound And MRI In Fetuses With Ventriculomegaly: Can Cortical Development Be Used To Predict Postnatal Outcome?
Author: Yi Li, Harvard Medical School, Class of 2011
Fetal ventriculomegaly (VM) is a condition where the fetal cerebral ventricles are dilated to greater than or equal to 10mm at the level of the atrium of the lateral ventricles. Our study aimed to assess the visualization of cortical maturation by ultrasound (US) and fetal MRI in fetuses referred for VM, and to investigate whether sulcal visualization can be used to predict postnatal developmental outcomes in fetuses with VM. We hypothesized that delays in ultrasound and MR visualization of sulci with respect to gestational age will correlate with cognitive and motor developmental delays in fetuses with VM.
318 fetuses referred for VM, with gestational age (GA) ranging from 15.7 to 42 weeks (average 26.3±5.9 weeks), were scanned by US and MRI. Four to six radiologists rated the visualization of the interhemispheric, sylvian, calcarine, parieto-occipital, cingulate, central, superior temporal, precentral, postcentral, inferior temporal, inferior frontal, insular, parietal, secondary temporal, secondary frontal, secondary parietal, superior occipital, inferior occipital, and tertiary frontal sulci by US and MR imaging. Majority opinion on sulcal visualization was compared amongst fetuses categorize by central nervous system (CNS) abnormality: normal, isolated VM, and VM with additional CNS abnormalities. Infants received postnatal neurodevelopmental testing at 6 months, 1 year, and 2 years of age and were categorized into normal development, mild developmental delays, and severe developmental delays. ANOVA was used to assess for correlations amongst gestational age, ventricular size, delays in sulcal visualization, and postnatal developmental outcome.
Sulci were visualized more frequently and at an earlier gestational ages by MR than by US. Sulcal visualization in fetuses with isolated VM lagged slightly behind visualization in normal fetuses; however, this difference was not statistically significant for most of the sulci. Sulcal visualization in fetuses with both VM and other CNS anomalies lagged significantly behind visualization in normal fetuses and fetuses with mild VM for virtually all sulci. In fetuses with isolated VM, delays in sulcal visualization did not correlate with live birth or with developmental outcome after adjusting for ventricular size.
Visualization of sulci is dependent on the imaging modality and the GA at which the fetus is imaged. There are minor lags in sulcal visualization for fetuses with isolated VM, but these do not correlate with postnatal neurodevelopmental outcome.