Perinatal magnetic resonance fetal lung volumetry and fetal lung-to-liver signal intensity ratio for predicting short outcome in isolated congenital diaphragmatic hernia and cystic adenomatoid malformation of the lung

AIM: To evaluate the usefulness of magnetic resonance imaging (MRI) in predicting the risk of lethal pulmonary hypoplasia in fetuses. METHODS: The subjects consisted of 15 fetuses (29-40 weeks' gestation), including fetuses with major malformation diagnosed on prenatal ultrasonography. MRI using a 1.5 T magnet and half-Fourier acquisition single-shot fast spin-echo sequences were applied to all fetuses at 29-36 weeks. Fetal lung-to-liver signal intensity ratio (LLSIR) was calculated by medians of region-of-interest analysis; estimated fetal bodyweight (FBW), by ultrasonography; and estimated fetal lung volume (FLV), by planimetric measurement of total lung volume. FLV/FBW was also calculated. The presence of the pulmonary hypoplasia in neonates was identified based on clinical and anatomico-pathological findings. Differences in LLSIR and FLV/FBW were analyzed for surviving and non-surviving neonates. RESULTS: Ten surviving neonates had a median LLSIR of 3.00, range: 1.60-4.40, while that in seven non-surviving neonates was 2.21, range: 0.70-3.72; no significant difference was found between the groups. Surviving neonates had a median FLV/FBW of 11.4, range: 7.1-15.7, while that in non-surviving neonates was 4.4, range: 3.1-5.7. FLV/FBW in non-surviving neonates was significantly lower than that of the FLV/FBW for surviving fetuses (P<0.05). CONCLUSIONS: Low FLV/FBW may be useful in prenatally predicting mortality in fetuses with pulmonary hypoplasia.