Magnetic resonance imaging in foetuses with bilateral moderate ventriculomegaly and suspected anomaly the corpus callosum on ultrasound scan

Objective: The diagnosis of anomalies of the corpus callosum (ACC) in foetuses with bilateral moderate ventriculomegaly (BMV) is difficult by means of ultrasound scan. The aim of this study was to examine the value of the additional investigation with magnetic resonance imaging (MRI) in foetuses with BMV and suspected ACC on ultrasound scan. Pathogenesis and clinical presentation of BMV and ACC are discussed. Methods: 41 foetuses with central nervous system (CNS) anomalies on ultrasound scan were assessed by ultrasonography and MRI from 1999 to 2001. Eight of these 41 foetuses presented with BMV and suspected ACC on ultrasound scan and were prospectively included in the study. Foetal investigations with sonography and MRI were analysed with regard to diagnostic confidence; results were correlated with post partum findings. Six of these 41 foetuses presented with BMV without suspected ACC on ultrasound scan and were retrospectively analysed. Results: Ultrasonography suspected ACC in 8 foetuses with BMV. MRI confirmed the presence of ACC in 4 of these 8 cases. MRI additionally showed ACC in two of the six retrospectively analysed foetuses with BMV without suspected ACC on ultrasound scan. Prenatal MRI diagnosis was confirmed after delivery in all cases. Conclusion: MRI is more sensitive than ultrasonography in the evaluation of ACC in foetuses with BMV. For prenatal screening ultrasound still remains the investigation of choice.