MR imaging of fetal central nervous system and ventriculomegaly

Objective. To evaluate MRI usefulness in diagnosis and management of fetuses with cerebral ventriculomegaly at US. Patients and methods. Sonography depicted cerebral ventriculomegaly in 61 fetuses. Management included MRI in all cases and infectious screening, and karyotype in 51 cases. Final diagnosis was supported by fetal autopsy (n = 24), postnatal follow-up > 6 months (n = 19), infectious screening or karyotype (n = 8), and MR imaging when diagnosis was obvious (n = 16). Results. MRI was more informative than ultrasonography in 32.8% of cases with identification of the etiology in 21.3% of cases. In 45% MRI and sonography were considered to be normal. In the remaining cases, MRI confirmed the ultrasound diagnosis of cerebral malformation. Ultrasonography never depicted more anomalies than MR imaging. The 2 false negatives were gyration disorders but MR imaging was performed too early. Conclusion. US is the imaging modality of choice in the evaluation of fetal anomalies but MRI has to be systematically performed in case of cerebral ventriculomegaly because MRI demonstrates its usefulness in patient counseling, even if there are a few false negative results.