Liver-to-thoracic volume ratio: use at MR imaging to predict postnatal survival in fetuses with isolated congenital diaphragmatic hernia with or without prenatal tracheal occlusion

Abstract

Objective: To evaluate the relationship of the liver-to-thoracic volume ratio (LiTR) by MRI with postnatal survival in foetuses with isolated congenital diaphragmatic hernia (CDH).

Methods: In 30 conservatively managed CDH foetuses and in 31 who underwent fetoscopic endoluminal tracheal occlusion (FETO), logistic regression analysis was used to investigate the effect on postnatal survival of the observed-to-expected (O/E) ratio of total foetal lung volume (TFLV), LiTR, gestational age at delivery, CDH side, intrathoracic position of the liver and, for those who underwent FETO, gestational age at FETO and occlusion period. For 19 foetuses undergoing FETO, a post-FETO MRI was available. The proportionate increase in O/E ratio of TFLV at 3-8 weeks after FETO was compared with the pre-FETO value and correlated with pre-FETO LiTR using linear regression analysis.

Results: For conservatively managed foetuses, only LiTR provided a significant prediction of postnatal survival. For foetuses undergoing FETO, LiTR and gestational age at delivery provided a significant independent prediction of postnatal survival. There was a significant inverse association between lung response and pre-FETO LiTR.

Conclusion: In foetuses with CDH with/without FETO treatment, the LiTR is predictive of postnatal survival at discharge. In foetuses treated with FETO, LiTR is predictive of post-FETO lung response.

Key points: • Congenital diaphragmatic hernia is usually managed conservatively before surgery soon after delivery • Fetoscopic endoluminal tracheal occlusion (FETO) has been introduced for severely affected foetuses • In conservatively managed CDH, the liver-to-thoracic volume ratio (LiTR) predicted postnatal survival best. • In severe CDH with prenatal FETO, LiTR also helped predict postnatal survival. • LiTR should be integrated into the prenatal decision-making for foetuses with CDH.