A comparative MR and pathological study on fetal CNS disorders

Object: We used MR after sonography to help us in prenatal counseling in 58 complicated pregnancies from 1998 to 2000. Methods: All fetal MR examinations were undertaken with a 1.5-T magnet using a body-phased-array coil and an ultrafast imaging technique, half-Fourier sin-le-shot turbo spin-echo (HASTE). Twelve fetuses were found to have major anomalies, and in each of these cases either delivery was induced or the pregnancy was terminated. In 6 of the fetuses, with anomalies of the central nervous system, postmortem examinations were then performed after they failed to survive, and these constitute the patient sample investigated in the current study. The fetal gestational ages in these 6 cases ranged from 24 to 32 weeks. MR imaging demonstrated morphological details of the anomalies. They were: alobar holoprosencephaly in 2, middle interhemispheric fusion in 1, alobar holoprosencephaly with Dandy-Walker malformations in 1, a Dandy-Walker variant in 1 and twin-twin transfusion syndrome with hypoxic-ischemic injury to the brain in 1. Conclusions: Postmortem examinations confirmed the MR diagnoses, and these observations support us in improving our understanding of the pathogenesis of fetal CNS anomalies.