Abstract
OBJECTIVES: Small bowel stenosis constitutes a frequent complication of Crohn's disease (CD). Early diagnosis of small bowel stenosis can guide individualized treatment, help avoid intestinal obstruction, and improve prognosis. This study aims to investigate the clinical value of small intestinal contrast ultrasound (SICUS) for diagnosing small bowel stenosis in CD patients, and to provide additional evidence for determining the insertion route of double-balloon endoscopy (DBE). METHODS: The results of SICUS, DBE, and computed tomographic enterography (CTE) from 80 patients with clinical suspicion of CD-associated small bowel stenosis treated at the Third Xiangya Hospital between March 2023 and December 2024 were retrospectively enrolled. The diagnostic accuracy of different examination modalities for small bowel stricture was analyzed. Correlations between the international bowel ultrasound segmental activity score (IBUS-SAS) measured by SICUS, characteristic ultrasound features of small bowel stricture, and DBE-confirmed stricture segments were assessed. RESULTS: Using DBE as the reference standard, SICUS showed better diagnostic performance for small bowel stricture than CTE [sensitivity 96.6% vs 91.5%, specificity 76.2% vs 70.0%, area under the curve (AUC) 0.864 vs 0.807]. With DBE as the comparator, SICUS demonstrated excellent agreement in localizing strictured jejunal and ileal segments (Kappa=0.867, P<0.001), while CTE showed moderate agreement in stricture segment localization (Kappa=0.558, P<0.001). The IBUS-SAS score in the SICUS-defined stricture group was significantly higher than that in the non-stricture group (77.26±21.74 vs 34.04±21.58, P<0.001). Bowel wall thickness (BWT) was significantly greater in the stricture group than in the non-stricture group [(7.28±3.18) mm vs (4.79±1.73) mm, P<0.001]. Small bowel loops with poor peristalsis had significantly greater BWT than loops with preserved peristalsis [(8.17±3.73) mm vs (5.48±1.71) mm, P<0.001]. SICUS imaging features including proximal dilation (OR=14.78, P=0.008), bowel angulation (OR=8.92, P=0.030), and poor peristalsis (OR=17.38, P=0.017) were all significantly associated with small bowel stricture. Ultrasound features of bowel angulation and poor peristalsis showed high specificity (90.0% and 85.7%) and high positive predictive value (87.5% and 91.4%) for diagnosing small bowel stricture. CONCLUSIONS: SICUS has high sensitivity and specificity for diagnosing active small bowel-stricturing CD, shows strong agreement with DBE results, and performs better than CTE. SICUS enables accurate localization of strictured small bowel segments, and its use as a reference for planning the DBE insertion route is feasible. SICUS ultrasound features including proximal bowel dilation, segmental angulation, and poor peristalsis are independent risk factors for detecting small bowel stricture under DBE.