Fetal MRI for CNS anomalies: an audit of 74 fetuses

Abstract

Although fetal MRI claimed to be superior to ultrasound in the investigation of fetal brain anomalies, this is based largely on comparison with routine ultrasound. We report our experience comparing fetal MRI and high-resolution ultrasound performed by fetal medicine specialists in the investigation of fetuses at high risk of, or after US detection of, cerebral anomalies. In 60 pregnancies, 66 ultra-fast MRI (0.5 Tesla Philips Apollo MR system) were performed on 74 fetuses following detailed high-resolution ultrasound (Acuson Sequoia TM 512). Forty-three fetuses had a CNS anomaly (25 cases of ventriculomegaly, 13 cases of posterior fossa pathology and five other) diagnosed on ultrasound and subsequently had a fetal MRI performed. In five cases (12%), the MRI provided additional information and in three of those five (7%) the management was revised. These cases involved agenesis of the corpus callosum, Dandy-Walker malformation and holoprosencephaly. No additional information on MRI was found in the fetuses with ventriculomegaly or in the monochorionic twin pregnancies complicated with an IUD of one twin, TOP or laser therapy. In the latter, no ischaemic brain lesions were seen.