Callosal dysgenesis in fetuses with ventriculomegaly: levels of agreement between imaging modalities and postnatal outcome.

OBJECTIVE: To assess neurodevelopmental outcome of fetuses diagnosed with callosal abnormalities after referral for ventriculomegaly.
METHODS: This sub-analysis of a prospective study of 430 fetuses, which were referred for ventriculomegaly and underwent sonography and magnetic resonance imaging (MRI), included those fetuses with a diagnosis of corpus callosal abnormalities after recruitment into the main study. Between three and six radiologists independently reviewed ultrasound and MR images and recorded central nervous system (CNS) abnormalities, with final diagnoses being decided by consensus. Postnatal outcomes of fetuses with callosal abnormalities were compared between those with and those without other abnormalities.
RESULTS: Callosal abnormalities were detected in 13% (58/430) of the fetuses referred with ventriculomegaly. Callosal dysgenesis was isolated in 24% (14/58) of these cases, with the remainder complicated by CNS, karyotypic or other major abnormalities. Five fetuses diagnosed prenatally as having isolated callosal abnormalities had additional CNS findings on postnatal assessment. Preconference kappa for callosal abnormalities was 0.76 for ultrasound and 0.78 for MRI, indicating that these investigations had a similar level of operator dependence. Neurodevelopmental outcome was normal or showed only mild delay that resolved in 67% (8/12) children with isolated callosal abnormalities compared to 7% (2/27) in those with non-isolated callosal abnormalities (P = 0.003).
CONCLUSION: Callosal abnormalities are present in a significant proportion of fetuses with a diagnosis of ventriculomegaly. Isolated callosal abnormalities are associated with normal neurodevelopmental outcome in approximately two-thirds of fetuses.