The use of motion-corrected 3D MRI can improve the visualization of congenital abnormalities in fetal hearts compared with either uncorrected 2D MRI or 2D echocardiography. This novel approach “offers the potential for a safe, reliable and highly complementary form of imaging of the fetal cardiovascular system”, conclude the researchers from London, UK.

Pregnant women are assessed using 2D echocardiography when a congenital cardiac abnormality is suspected, but if further diagnostic information is needed, the options for reliable secondary imaging are limited. Use of fetal MRI is well-established for other organs (such as the brain), but is susceptible to movement of the fetus, especially for 3D imaging. Therefore, the investigators aimed to test the use of MRI with novel, motion-corrected, 3D image-registration software in the diagnosis of congenital heart disease.

The study included 85 women carrying a fetus with known or suspected congenital heart disease on the basis of 2D echocardiography who attended the fetal cardiology unit at Evelina London Children’s Hospital, UK. Gestational age at the time of MRI was 24–36 weeks. MRI data were obtained as overlapping stacks of 2D images and processed using a bespoke, open-source reconstruction algorithm to generate a super-resolution 3D volume of the fetal thorax.

Vascular measurements obtained using 3D MRI showed good overall agreement with 2D echocardiography. Visualization of fetal vascular structures was more effective with 3D MRI (97%) than with 2D MRI (53%). Moreover, for 90% of the structures visualized, the diagnostic quality of the images was better with 3D MRI (or the same as with 2D MRI for the remaining 10%). The detailed 3D images obtained could be highly informative for counselling, planning surgery and coordinating postnatal care.