Fetal MRI assessment of mediastinal shift angle in isolated left congenital diaphragmatic hernia: A new postnatal survival predictive tool?

Objective To quantify the mediastinal shift angle (MSA) in fetuses with isolated left congenital diaphragmatic hernia (CDH) by magnetic resonance imaging and evaluate survival. Method Fetuses from singleton pregnancies with isolated left CDH were matched for gestational age with controls without thoracic malformations. For all fetuses the MSA was determined by two operators and inter-operator variability and differences between cases and controls were investigated. For all cases total fetal lung volume (TFLV) was calculated and the correlation between MSA and TFLV was assessed, and its predictive value towards survival was determined. Results Thirty-four fetuses were included as cases and 42 as controls. The mean gestational age for assessment of CDH fetuses was 32 weeks (range 27-38). Twenty-four fetuses survived until discharge and 10 did not. There was an excellent inter-operator reliability for measuring the MSA and a significant difference between MSA in cases and controls. There was an inverse correlation between MSA values and survival, a correlation between TFLV and survival and an inverse correlation between MSA and TFLV. The area under the ROC curve for MSA in predicting survival was 0.931 (95% CI 0.851-1.000). Conclusion The MSA measured late in gestation correlates with postnatal survival in patients with isolated left CDH.