Utility of fetal MRI for workup of fetal central nervous system anomalies in an Australian maternal-fetal medicine cohort.

Abstract

To evaluate how fetal MRI is influencing current clinical practice and outcomes for central nervous system (CNS) anomalies in the Australian maternal-fetal medicine (MFM) setting. Retrospective audit of cases January 2008-August 2013 referred for MFM ultrasound and MRI for suspected fetal CNS anomaly. Demographics, referral information, initial MFM diagnoses and investigations, MRI diagnoses, subsequent pregnancy management and perinatal outcome were examined. Fifty-seven women (41 singleton, 16 twin pregnancies) were seen at mean gestation of 23.7 ± 6.5 weeks. Major referral indications included ventriculomegaly (VM, 39%) and posterior fossa anomaly (PFA, 18%). MRI was performed at mean 27.2 ± 5.3 weeks. Diagnosis was altered from ultrasound in 31/57 cases (54%); 14 improving and 17 worsening prognosis. MRI findings worsening prognosis were more significant VM and PFA, agenesis of the corpus callosum, neuronal migration disorders and intraventricular haemorrhage. TOP or selective reduction occurred in 11 of 57 cases after full clinical workup (six where MRI worsened prognosis, five where MRI confirmed US poor prognosis). Mean gestation at birth was 37.2 ± 4.1 weeks for continuing pregnancies. There were nine cases of additional postnatal diagnoses, including four CNS anomalies. After neonatal workup, physical and/or developmental delay was anticipated for at least 14 of 43 (33%) infants. MRI added significant diagnostic information in about half the cases referred for workup of suspected CNS anomaly. In six of 17 cases where MRI worsened prognosis, TOP was chosen. Both additional CNS and non-CNS anomalies were diagnosed postnatally in 20%, emphasising the uncertain prognosis for, and evolution of, suspected CNS anomaly in fetuses.