P0347The comparative efficacy of diagnostic modalities- Intestinal Ultrasound compared with CT Enterography against Single Balloon Enteroscopy as gold standard in small bowel Crohn’s Disease

Abstract Background Crohn’s disease (CD) is a chronic, relapsing inflammatory condition of the gastrointestinal tract, often involving the small intestine with characteristic transmural inflammation. Diagnosis is complicated by its heterogeneous clinical presentation and the limitations of conventional diagnostic modalities in assessing both mucosal and transmural disease. While endoscopy remains the gold standard for mucosal evaluation, it is invasive and limited in reach, particularly for mid and proximal small bowel segments. CT enterography (CTE) offers excellent transmural and extramural detail but is limited by radiation exposure. Intestinal ultrasound (IUS), a non-invasive, bedside, and radiation-free modality, is increasingly recognized for its utility in the diagnosis and monitoring of CD.This study aimed to evaluate and compare the diagnostic performance of IUS and CTE in detecting small bowel lesions in patients with suspected or established Crohn’s disease, using single-balloon enteroscopy (SBE) as the reference standard. Methods In this prospective observational study conducted at a tertiary referral centre over 14 months, 50 patients with suspected or confirmed small bowel CD were enrolled. Each patient underwent clinical evaluation, laboratory testing, and sequential imaging with IUS, CTE, and SBE. Results IUS detected bowel wall thickening in 88%, increased Doppler vascularity in 54%, luminal narrowing in 36% and mesenteric lymphadenopathy was noted in 34% of cases. CTE identified bowel wall thickening in 88%, mural stratification in 78%, comb sign in 60%, strictures in 26%, and fistulae in 12% of patients. SBE confirmed mucosal ulcerations in 86% of cases and enabled histological diagnosis in 80%. IUS showed a sensitivity of 90.91% and a PPV of 92.11% for bowel wall thickening, with specificity at 33.33%. For vascularity, IUS had a sensitivity of 66.67%, specificity of 65%, and diagnostic accuracy of 66%. In comparison, CTE demonstrated 100% sensitivity for mucosal/submucosal involvement, higher specificity (89.47%) for strictures, and better agreement with SBE findings. Conclusion Both IUS and CTE demonstrated high diagnostic efficacy in evaluating small bowel Crohn’s disease, with CTE showing slightly higher overall accuracy, particularly for transmural pathology. However, IUS proved to be a reliable, non-invasive, and accessible tool, especially valuable for ileal disease and longitudinal monitoring. The findings reinforce the complementary roles of IUS, CTE, and SBE, and support the integration of IUS into routine clinical workflows to enhance early diagnosis, reduce radiation exposure, and enable tailored, patient-centric management of small bowel CD. References: 1. Yigit B, Sezgin O, Yorulmaz E, Erturk MS, Erdem U, Yanc U, et al. Effectiveness and Power of Abdominal Ultrasonography in the Assessment of Crohn’s Disease Activity: Comparison with Clinical, Endoscopic, and CT Enterography Findings. Turkish Journal of Gastroenterology. 2022 May 13;33(4):294–303. 2. Giuffrè M, et al. Contrast-enhanced ultrasound in the assessment of Crohn’s disease activity: comparison with computed tomography enterography. Ultrasound Med Biol. 2022;48(3):345– 353. 3. Novak KL, Tutein Nolthenius CJ, Samaan MA, et al. International Bowel Ultrasound Segmental Activity Score (IBUS-SAS): a multisite reliability study in Crohn’s disease. J Crohns Colitis. 2021;15(4):609–616. Conflict of interest: Tarannum, Neha: No conflict of interest Patel, Rajendra: None Kalapala, Rakesh: No conflict of interest Reddy, Harshini: No conflict of interest Shah, Sonam: NONE Banerjee, Rupa: RB has received grants/research support from Asian Healthcare Foundation, and the Leona M and Harry B Helmsley Charitable Trust Advisory board fees from Abbott, AstraZeneca, Abbvie, Cadila, Cipla,, Dr Reddy Labs, Eli Lilly, Emcure, Ferring Pharma, Hetero Drugs, Janssen, MSN Labs, Mankind Pharma, Menarini, Micro Labs, Pfizer,, Sun Pharmaceuticals, Takeda Pharmaceuticals, Torrent, Waterley, and Zydus.