O1108: Fetal Lung Volumes Measured by MRI Predict Pulmonary Morbidity Among Infants with Giant Omphaloceles

Background: Giant omphaloceles (GO) are rare congenital anomalies often diagnosed in utero. Like congenital diaphragmatic hernias (CDH), GO are associated with pulmonary hypoplasia and postnatal respiratory complications. While total lung volumes (TLV) measured by fetal MRI can prognosticate postnatal outcomes for CDH, little data exists to support its applicability to GO. We hypothesize that late gestation TLV, as well as the observed-to-expected TLV (O/E TLV) ratios, measured by prenatal MRI may correlate with postnatal pulmonary morbidity among fetuses with GO.

Methods: We performed a retrospective review of GO managed at our institution between January 1, 2012 and January 1, 2022. Patients with prenatally diagnosed chromosomal anomalies were excluded. To specifically address the prognostic benefit of fetal MRI TLV measurements, we limited our cohort to those who received at least one prenatal MRI at our fetal treatment center and were subsequently managed within our NICU. Fetal MRI TLV between 32-36 weeks’ gestation and O/E TLV throughout gestation were calculated and correlated with postnatal outcomes. For patients with multiple fetal MRIs, the highest O/E TLV was used for analysis.

Results: Twenty-six patients met our strict inclusion criteria. MRIs were obtained at different gestational ages varying from 18-36 weeks. We first analyzed those with an MRI between 32-36 weeks’ gestation (n=17) to determine if late gestation TLV predicts postnatal outcomes. Those requiring delivery room intubation had significantly lower fetal TLV (Table). Three fetuses had a TLV of less than 35 mL, one of whom died from respiratory failure and the other two required tracheostomy. Prenatal TLV did not correlate with length of hospitalization or need for supplemental oxygen after discharge. Next, all 26 fetuses were analyzed utilizing O/E TLV which adjusts for varying gestational age of attainment. In addition to correlating with need for delivery room intubation and need for tracheostomy, O/E TLV also predicted survival (Table). O/E TLV, like TLV, did not predict length of hospitalization or need for supplemental oxygen after discharge.

Conclusion: Fetal MRI TLV measured between 32-36 weeks’ gestation and O/E TLV measured within the second and third trimester predict the need for delivery room intubation. Furthermore, O/E TLV predicts need for tracheostomy and survival to discharge. As omphaloceles have a strong association with cardiac and chromosomal anomalies, additional variables likely influence length of hospitalization and discharge on supplemental oxygen. This data supports the use of fetal MRI to predict postnatal pulmonary morbidity associated with giant omphalocele. Additionally, it may be a useful tool to select patients who will better tolerate an amnioinversion or Shuster procedure versus those who should be managed with the “paint and wait” delayed repair strategy.