P0483 Assessment of Disease Activity in Pediatric Inflammatory Bowel Disease Using Intestinal Ultrasound: A Comparative Diagnostic Analysis
Authors: Massironi S , Mulinacci G , Zuin G , Pirola L , Mancini F , Carzaniga V , Zucchini N , Dinelli M E , Maino M 
Published: January 2025

Abstract

Background
Intestinal ultrasound (IUS) is increasingly utilized as a point-of-care tool for patients with ulcerative colitis (UC). Non-invasive monitoring is vital for managing disease progression and guiding therapeutic interventions, particularly in pediatric UC patients. The Milan Ultrasound Criteria (MUC), Ulcerative Colitis Intestinal Ultrasound Score (UC-IUS), and Civitelli score are promising tools for real-time assessment of disease activity, potentially reducing reliance on invasive procedures like endoscopy.
Aim of the study is to evaluate the correlation and diagnostic efficacy of MUC, UC-IUS, and Civitelli scores in assessing disease activity in pediatric UC patients, with endoscopic findings as the comparative standard and histological evaluation using the Nancy Index.

Methods
A prospective cohort (from January to June 2024) of 34 pediatric UC patients underwent IUS and colonoscopy to assess disease activity using MUC, UC-IUS, and Civitelli scores. Assessments were conducted within a 7-day interval, with no therapeutic changes between procedures. Diagnostic accuracy was determined using receiver operating characteristic (ROC) curves, with endoscopy as the reference standard, and histological parameters assessed in a subset of patients using the Nancy Index.

Results
The study included 34 pediatric UC patients (median age: 14.7 years; 65% male) with varied disease severities and durations (median duration: 12.6 months; median PUCAI: 30; median fecal calprotectin: 1041 µg/g). Bowel wall thickness (BWT) correlated significantly with all IUS scores; however, no correlation was observed between BWT and baseline Mayo endoscopic disease activity. The area under the curve (AUC) was 0.528 (CI: 0.348–0.704) for MUC, 0.602 (CI: 0.418–0.768) for UC-IUS, and 0.572 (CI: 0.388–0.742) for the Civitelli score, indicating moderate diagnostic accuracy. While differences among scores were not statistically significant, UC-IUS demonstrated the highest accuracy.
In 16 patients with available Nancy Index data, the AUC values were 0.500 for MUC, 0.579 for Civitelli, and 0.563 for UC-IUS, further supporting moderate accuracy.

Conclusion
Both MUC, Civitelli, and UC-IUS scores provide moderate diagnostic accuracy in assessing pediatric UC, though potentially less effective than in adult populations.
UC-IUS, with its emphasis on vascularization, haustration and wall thickness, may offer enhanced sensitivity in pediatric patients. These features are particularly significant in pediatric cases where the disease is recent and the wall often is not very thickened, yet highly vascularized. Lowering the cut-off for bowel wall thickness may improve accuracy in children.

References
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2.Allocca M, Dell’Avalle C, Craviotto V, et al. Predictive value of Milan ultrasound criteria in ulcerative colitis: A prospective observational cohort study. United European Gastroenterol J. 2022;10:190-197.
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