Intestinal Ultrasound Scan in Acute Severe Ulcerative Colitis in Children: A Multicenter Prospective Study on Behalf of the Porto Inflammatory Bowel Disease Working Group of European Society for Paediatric Gastroenterology Hepatology and Nutrition

Background & aims: The aim of this study was to evaluate the potential role of intestinal ultrasound scan (IUS) in predicting short-term treatment outcomes in pediatric acute severe ulcerative colitis (ASUC). Methods: This prospective longitudinal study was conducted across 10 European centers. Biologic-naïve children with ASUC were included. Each patient underwent 2 IUS, the first within 48 hours of initiating intravenous corticosteroids, and the second between day 5 and 7 of treatment. Key metrics assessed included colonic wall thickness (CWT), colonic wall stratification (CWS), and colonic wall blood flow via power Doppler. The Milan ultrasound score was also calculated for each colonic quadrant. Results: The study prospectively enrolled 60 patients (61.7% girls; median age at enrollment, 13.5 years). Escalation to infliximab was required in 39 patients (65%) who were corticosteroid nonresponders. Nonresponders had significantly higher CWT assessed in the left-lower quadrant (LLQ) (6 vs 4.2 mm, P < .001) and left upper quadrant (5 vs 4 mm, P = .003) and had more frequent hypervascularity (Limberg's score ≥3) assessed in the same sections. Receiver operator characteristic curve analysis identified LLQ CWT >5 mm (area under the curve [AUC] = 0.819) and Milan Ultrasound Criteria >7.8 (AUC = 0.834) as optimal cutoffs for predicting steroid resistance. Ten patients (16.7%) who did not respond to medical therapy underwent colectomy within the 8-week period of the study. At the second IUS, CWT >4.8 mm and Milan Ultrasound Criteria >8.7 in LLQ were associated with medical therapy failure (AUC = 0.844 and 0.878, respectively). Patients in steroid-free clinical remission at week 8 had lower CWT (3.5 vs 5 mm, P = .037) and Milan Ultrasound Criteria (5.3 vs 8.7, P < .001) at the second IUS. Conclusions: IUS is an effective noninvasive tool to predict first-line therapy failure and the need for colectomy in patients with ASUC.