Objectives: to evaluate the additional information of second trimester magnetic resonance imaging (MRI) compared to ultrasound in fetuses with identified or suspected central nervous system (CNS) anomalies and to study the clinical impact of the information on pregnancy management.
Design: prospective study during 2004-2007. The fetal MRI examination was planned to be performed within 3 days after the ultrasound. Setting. Uppsala University hospital.
Material: twenty-nine pregnant women in whom second trimester ultrasound identified or suspected fetal CNS anomalies.
Main outcome measures: evaluation of the additional information gained from MRI and the consequence it had on pregnancy management.
Results: the mean interval between ultrasound and MRI was 1.6 days (range 0-7). In 16 fetuses (55%), MRI verified the ultrasound diagnosis but provided no additional information, while in 10 (35%) MRI gave additional information without changing the management. In 3 (10%), MRI provided additional information that changed the management of the pregnancy. Two of these women were obese.
Conclusions: fetal MRI in the second trimester might be a clinically valuable adjunct to ultrasound for the evaluation of CNS anomalies, especially when ultrasound is inconclusive due to maternal obesity.