Additional value of fetal magnetic resonance imaging for prenatal diagnosis: A retrospective study.

Objective: This study aimed to evaluate the utility of fetal MRI in prenatal diagnosis.

Methods: A retrospective study was conducted, including all pregnant women who underwent fetal MRI at a single French university center from 2018 to 2022. Fetal MRI findings were deemed "concordant" if they matched the ultrasound diagnosis. Fetal MRI provides "useful information" for perinatal management and prognosis when the postnatal prognosis or prenatal follow-up are modified, especially if it leads to the diagnosis of a "severe pathology," potentially warranting the termination of pregnancy under French law. Fetal MRI was considered "reassuring" if its results contradicted the ultrasound diagnosis.

Results: A total of 304 cases were analyzed. The primary indication for fetal MRI was central nervous system (CNS) pathology (170/304; 57%), followed by abdominal or thoracic pathology (51/304; 17% and 38/304; 13%, respectively). Overall, the concordance between fetal MRI and ultrasound was 83% (251/304). The MRI findings indicated a worse prognosis for 4% (12/304) of fetuses and were reassuring compared to ultrasound in 9% of fetuses (22/304). For CNS pathologies, the concordance was 80% (138/172), with MRI leading to the diagnosis of a severe condition in 6% (11/172) of fetuses and were reassuring compared to ultrasound in 9% (16/172) of fetuses.

Conclusions: Fetal MRI modified the fetal prognosis in 13% of fetuses, with 4% having greater severity and 9% having no malformation. The additional value of fetal MRI is primarily observed in CNS pathologies.