(181) Fetal MRI Versus Ultrasound Ratios for Predicting Perinatal Outcomes in Prenatally Diagnosed Omphalocele

Complications associated with pulmonary hypoplasia are the primary cause of morbidity and mortality in neonates with omphalocele. Various prognostic indicators have been employed to identify neonates at greatest risk. Recently, fetal MRI lung volumetric analysis has become more commonplace, despite being costly and requiring access to specialized centers. This study compares fetal MRI-derived fetal lung volumes and ultrasound-derived ratios as prognostic tools in fetuses with prenatally detected omphalocele (PDO).


 

Study Design:

 This retrospective cohort study included all pregnancies with PDO who underwent evaluation at our fetal center from 2007-2023. Pregnancies with fetal aneuploidy or concurrent life-limiting fetal anomaly were excluded. MRI-derived fetal lung volume analysis calculated the observed-to-expected total fetal lung volume (O/E TLV) ratio. Omphalocele diameter (OD), abdominal circumference (AC), and head circumference (HC) were recorded, and OD/HC and OD/AC ratios were calculated. The primary outcome was neonatal death. Secondary outcomes included the need for intubation, prolonged intubation >30 days, pulmonary hypertension, and time to full feeds. Cutoffs for the prediction of neonatal outcomes were determined by receiver operating characteristic curve (ROC) analysis.

 
 

Results:

53 pregnancies met the inclusion criteria. Omphaloceles ranged in size from 0.9-20cm in diameter. 8 neonates (15%) experienced neonatal death (Table 1). The most frequent secondary outcome was the need for intubation, occurring in 22 (42%) neonates. Using an optimal cutoff of >0.58, MRI-based O/E TLV outperformed ultrasound-based ratios in predicting neonatal death (sensitivity 0.75; specificity 1.0; AUC 0.92), as well as most of the secondary outcomes (Table 2). Among ultrasound-based ratios, OD/AC consistently outperformed OD/HC.


 

Conclusion:

Fetal MRI O/E TLV outperforms ultrasound-based ratios in predicting perinatal severe morbidity and neonatal mortality in PDO. These findings underscore the need for more advanced ultrasound-based measures to increase accessibility to high-quality care.