Abdominal Ultrasound Scanning for NEC in Babies at the Threshold of Viability: A Single Centre Experience

Neonatal units are caring for increasing numbers of babies born <24 weeks gestation. These babies are vulnerable to developing necrotising enterocolitis (NEC). Their presentation is often atypical, both clinically and radiologically. Optimal diagnostic strategies are not yet known. We report our experience of abdominal ultrasound scanning (AUSS) to clarify its role.

All babies in a single neonatal surgical centre born <24 weeks gestation undergoing AUSS for suspected NEC from January 2015 to January 2023 were included. We compared abdominal ultrasound findings with plain radiographs and correlated these to intraoperative findings.

Thirty-nine babies born <24 weeks gestation were diagnosed with NEC during the study period, and of these seventeen had an AUSS and formed the study cohort. Twelve underwent laparotomy at which NEC was confirmed, and the remaining five were managed non-operatively. Abdominal radiograph findings were: Paucity of gas (12), gaseous dilatation (2), paucity of gas with proximal dilatation (1), pneumatosis (1), and lucencies over the liver (1). In twelve cases who underwent surgery, AUSS findings were (more than one possible): Complex ascites (6), inflamed bowel (4), aperistaltic bowel (3), mass/collection (4), pneumatosis (1). All had NEC confirmed at laparotomy. In five cases who did not progress to surgery, findings were: Simple free fluid (2), pneumatosis (2), inflamed bowel (1), aperistaltic bowel (1). None of these cases subsequently underwent surgery or died of complications of NEC.

AUSS is a useful imaging modality for NEC in babies born <24 weeks gestation. It can reliably identify babies who would benefit from surgery.

Retrospective cohort study.