Effect of Adding Bowel Ultrasound to Standard Radiography for Suspected Necrotizing Enterocolitis: A Randomized Clinical Trial

ABSTRACT Importance Bowel ultrasound (BUS) offers real-time assessment of bowel integrity and perfusion, but its clinical impact on diagnosis and management of necrotizing enterocolitis (NEC) remains unclear. Objective To evaluate whether adding BUS to standard abdominal radiography (AXR) improves diagnostic decision-making and clinical outcomes in infants evaluated for suspected NEC. Design Randomized clinical trial. Setting Level IV neonatal intensive care unit (NICU) of a freestanding children’s hospital (BUS-experienced) and a level III NICU of an adult hospital (BUS-naïve). Participants Infants undergoing imaging for suspected NEC. Interventions Infants randomized by calendar month to AXR alone or AXR + BUS. Clinical management followed standard NICU practice. Main Outcomes and Measures The primary outcome was time to full enteral feeds within 30 days of NEC concern. Secondary outcomes included duration of antibiotics and bowel rest. Analyses followed the intention-to-treat principle, with per-protocol sensitivity analyses. Post-imaging survey assessed the perceived impact of adding BUS on diagnostic and therapeutic decision-making. Results A total of 169 infants (199 NEC evaluations; 114 AXR, 85 AXR + BUS) were included; 84% were preterm, and 62% were from the level IV NICU. Among infants ultimately classified as extended NEC rule-out (NEC excluded after repeated imaging evaluations), BUS was associated with faster recovery to full feeds (median 4 vs 8 days; hazard ratio [HR], 1.89; 95% CI, 1.23–2.91). No differences were observed among infants with quick NEC rule-out (NEC excluded after single imaging evaluation) or confirmed NEC . BUS did not prolong antibiotic or bowel rest duration. Per-protocol analysis yielded similar results for all outcomes. Neonatologists reported greater diagnostic and therapeutic confidence with BUS. Conclusions and Relevance In this dual-site randomized trial, adding BUS to standard AXR accelerated feeding recovery among infants with prolonged diagnostic evaluations for suspected NEC, without increasing adverse events. BUS may enhance diagnostic confidence and streamline management in cases of diagnostic uncertainty. Larger multicenter studies are warranted to confirm these findings and guide implementation across NICU settings. Trial Registration ClinicalTrials.gov Identifier NCT05573113 Key Points Question Does adding bowel ultrasound to standard radiography improve outcomes among infants evaluated for suspected necrotizing enterocolitis? Findings In this randomized diagnostic trial of 169 infants, adding bowel ultrasound shortened time to full feeds among infants with prolonged diagnostic evaluations without increasing adverse events. Meaning Bowel ultrasound may enhance diagnostic confidence and expedite feeding recovery in infants with diagnostic uncertainty for NEC.