Prenatal diagnosis of congenital brain malformation primarily relies upon prenatal sonography as method of choice for screening due to its low cost, wide availability and safety. However, it’s not without limitations such as poor visualization depending on fetal position and scull ossification, low tissue definition, and operator variability. Advances in technology resulting in rapid pulse sequences enabled fetal MRI to become a significant and complementary tool in prenatal diagnosis. After detection of a brain abnormality on routine sonography, fetal MRI is used to confirm or exclude it, also allowing more precise characterization and detection of associated malformations not seen on sonography.

In this paper we address fetal MR imaging of brain and spine malformations. Also, a series of 167 fetal MRI examinations, performed at our institution during a period of 6 years, is reviewed. Pregnant women between 20^th and 36^th week of gestation underwent MRI because of suspected fetal pathology, high risk or history of severe brain malformation in previous pregnancy. No pathology was detected in 54 cases (32, 3%) and in 113 cases (67, 7%) fetal MRI was abnormal. Most frequent anomalies found were hydrocephalus (37,1%) in five cases associated with other anomalies, corpus callosum anomalies (30,1%), Chiari II malformation (14,2%), cephaloceles (12,4%) and schizencephaly (8%). We also found two cases of anencephaly and one sacrococcygeal teratoma. Fetal MRI provided detailed visualization of fetal neuronal structures and confirmed malformations seen on ultrasound, and significantly influenced pregnancy outcome in 11% of cases.