OC14.01: Is there a role for magnetic resonance in addition to ultrasound in the prenatal diagnosis of fetal anomalies?

Abstract

To evaluate the accuracy of MRI compared to 2D-3D ultrasound in the diagnosis of fetal malformations. We retrospectively reviewed the prenatal and postnatal records for all the cases of prenatal diagnosis of fetal anomaly that underwent ultrasound and MRI in the period 2001–2009. Mean gestational age at ultrasound and MRI diagnosis were 28 ± 4 weeks 30 ± 4 weeks' gestation respectively. Postnatal follow-up was always recorded. 274 consecutive cases were registered including 126 central nervous system anomalies (46%); 42 thoracic defects (15%); 20 genitourinary malformations (7%); 15 gastrointestinal anomalies (6%) and 71 miscellaneous (26%). In 244 (89%) both ultrasound and MRI findings were in agreement with postnatal diagnoses. MRI changed the US diagnosis in 16 (5,8%) cases. Relevant additional information were provided in 7 (2,5%) cases: 3 central nervous system anomalies; 3 thoracic defects; 1 abdominal malformations. Ultrasound was more accurate than MRI in 4 (1,4%) cases: 1 case of placenta previa; 1 exomphalos; 1 CCAM in a twin pregnancy; 1 hypoplasia of corpus callosum. In 9 (3,2%) cases, the diagnoses at both US and MR imaging were not correlated with postnatal outcome. Prenatal US remains the primary fetal imaging modality. Prenatal diagnosis of even complex malformations was accurate in over 90% of cases. In a few selected patients in our experience, particularly in late pregnancy, MRI may however add relevant information.