Diagnosi prenatale delle malformazioni fetali: ecografia e risonanza magnetica a confronto in 11 anni di esperienza

Objective: To evaluate the accuracy of fetal magnetic resonance (MRI) compared to 2D-3D ultrasound in the prenatal diagnosis of congenital anomalies. Materials and methods: We retrospectively evaluated all cases of fetal malformations underwent "expert" ultrasound and MRI in our Hospital from October 2001 to October 2012. The gestational age at ultrasound and magnetic resonance were respectively 28 and 30 weeks. The ultrasound diagnosis was compared with the MRI and then with the postnatal diagnosis. Results: 383 cases were selected, with a sonographic diagnosis or suspected fetal "complex" malformation or obstetric history of positive prenatal infections, evaluated with 2D-3D ultrasound, MRI and complete of follow-up. The study population included: 196 anomalies of the central nervous system (CNS) (51.2%), 73 thoracic defects (19.1%), 20 abnormalities of the face and the neck (5.2%), 29 malformations of the gastrointestinal tract (7.6%), 37 genitourinary defects (9.7%) and 28 cases with other indications (7.3%). An agreement between ultrasound, MRI and postnatal diagnosis was observed in 289 cases (75.5%) and was greater for the CNS anomalies, 156/196 cases (79.6%), compared with the others congenital defects, 133/187 cases (71.1%). The MRI has added important diagnostic information in 42 cases (11%): 21 CNS abnormalities, 2 facial and neck defects, 7 thoracic malformations, 6 gastrointestinal anomalies, 5 genitourinary defects and 1 case of suspected lumbar emivertebra. The ultrasound was more accurate than MRI in 15 cases (3.9%). In 37 cases (9.7%) both techniques were not correlated with postnatal findings. Conclusions: Prenatal ultrasound is still the primary fetal imaging modality. In some complex CNS and extra-CNS anomalies, particularly in late pregnancy, MRI can add relevant information.