Fetal MR imaging of congenital diaphragmatic hernia.

Fetal magnetic resonance (MR) imaging plays a number of roles in the evaluation and management of congenital diaphragmatic hernia (CDH). Fetal MR imaging has proved valuable for anatomic assessment, determination of the specific type of CDH on the basis of which organs are involved and the effect of the hernia contents on adjacent structures, evaluation and exclusion of hernia-related complications and associated malformations (some of which may suggest an underlying syndrome), calculation of lung volume and liver herniation measurements, and calculation of the diameters of the pulmonary arteries and aorta. All of these parameters may aid the fetal care team in terms of prenatal counseling and perinatal planning. In addition, fetal MR imaging plays a role in guiding experimental fetal therapy (eg, tracheal balloon occlusion), with preliminary results showing an increase in observed-to-expected lung-to-head ratio and total fetal lung volume during the tracheal occlusion period, leading to improved neonatal survival.