Comparison of imaging findings of surgical necrotizing enterocolitis between extremely preterm and preterm infants

Background

Advances in neonatal care have improved survival of extremely premature infants (<28 weeks gestational age (GA)), especially with necrotizing enterocolitis (NEC).

Objective

To evaluate if imaging features of NEC differ between extreme premature and premature infants.

Materials and methods

We retrospectively reviewed the abdominal radiograph and/or ultrasound obtained immediately prior to surgically proven diagnosis of NEC in our neonatal intensive care unit infants January 2020-January 2025. Two blinded pediatric radiologists reviewed imaging, and a third acted as a tie-breaker in case of discordant review. Patients were stratified by GA (<28 weeks vs. ≥28 weeks) and birth weight (<1,500 g vs. ≥1,500 g). Chi-square test was used to assess differences in imaging findings.

Results

Ninety patients met inclusion criteria (median age 21.5 days); 43.3% (n=39) female. In total, 56% (50/90) had GA <28 weeks and 86% (77/90) had birth weight <1,500 g. All 90 patients had abdominal radiographs; only 19% (17/90) had bowel ultrasound. In unadjusted analyses, we found that infants with GA <28 weeks were more likely to demonstrate paucity of bowel gas (OR 4.64, 95%CI 1.41-15.2, P-value 0.01), and less likely to have fixed bowel loops (OR 0.16, 95%CI 0.04-0.62, P-value 0.01) or pneumatosis intestinalis (OR 0.38, 95%CI 0.15-0.96, P-value 0.04). After adjusting for birth weight, those with GA <28 weeks were less likely to show pneumatosis intestinalis on radiographs (OR 0.31 (95%CI 0.11, 0.87), P-value 0.03) as compared to infants ≥28 weeks GA. For ultrasound findings, no imaging features were significantly different based on stratification based on gestation age or birth weight (all P>0.05).

Conclusion

Extremely premature (<28 weeks) and very low birth weight (<1,500 g) infants tend to show fewer classic radiographic signs of NEC, i.e., pneumatosis intestinalis and fixed bowel loops, and more often exhibit a paucity of bowel gas.

Graphical abstract