ABSTRACT
Background:
Fetal ultrasound has limitations, especially if the
patient is obese or in cases with
oligohydramnios.
Magnetic resonance imaging (MRI) can then be used as a
complement, but only few studies have focused on examinations in the
second trimester.
Purpose:
To validate MRI as a
complement to
diagnose fetal anomalies in the
second trimester. Material and
Methods:
This
retrospective study retrieved data from January 2008 to July 2012 from the
Fetal Medicine Unit and Department of
Radiology at Uppsala
University Hospital. Ultrasound and MRI findings were reviewed in 121
fetuses in relation to the final
diagnosis, including
postpartum follow-up and
autopsy results.
Results:
Of the 121
fetuses, 51 (42%) had a CNS anomaly and 70 (58%) a non-CNS anomaly diagnosed or suspected. MRI provided additional information in 21% of all cases without changing the management and revealed information that changed the management of the
pregnancy in 13%. When a CNS anomaly was detected or suspected, the MRI provided additional information in 22% and changed the management in 10%. The corresponding figures for non-CNS cases were 21% and 16%, respectively. The proportion of cases with additional information that changed the management was especially high in
patients with a BMI >30 kg/m2 (25%) and in
patients with
oligohydramnios (38%). In five cases in category III, false-positive ultrasound findings were identified.
Conclusions:
MRI in the
second trimester complements ultrasound and improves
diagnosis of fetal CNS- and non-CNS anomalies especially when
oligohydramnios or
maternal obesity is present.