Raising the Bar in IBD Imaging: Multidimensional Intestinal Ultrasound Training Improves Accuracy and Competency

Accurate assessment of inflammatory bowel disease (IBD) is essential to guide management and improve outcomes. Intestinal ultrasound (IUS) has emerged as a valuable noninvasive, cost-effective, point-of-care technique for real-time evaluation of intestinal and extraintestinal features, supporting immediate clinical decision-making and monitoring. However, standardized training is required to ensure competency and reproducible assessments. While evidence shows that appropriate training reduces performance gaps between less experienced and expert operators, data on parameter-specific learning curves remain limited.

This prospective, multicenter, observational study characterized learning curves and competency thresholds for basic (bowel wall thickness [BWT], bowel wall stratification [BWS], vascularization, mesenteric hypertrophy, and lymph nodes) and advanced IUS parameters (dilation, fistulas, collections, free peritoneal fluid). Eight trainees were paired with 8 experts to complete a standardized 3-phase training program consisting of theory, 30 supervised practical examinations, and 99 independent assessments. Trainee-expert agreement served as a surrogate marker of clinical competence.

Most examinations were performed for IBD monitoring (73.3%), with a high prevalence of increased BWT and vascularization, whereas advanced findings were less common. Basic parameters exhibited excellent baseline agreement, with gradual and modest improvement over time (from κ=0.792 to κ=0.842). Conversely, advanced parameters showed lower initial agreement but steeper learning curves (from κ=0.728 to κ=0.854), particularly during later training phases.

Small-bowel dilation and free-fluid detection demonstrated the greatest improvements despite being advanced variables (from κ=0.674 to κ=0.921 and k=0.598 to κ=0.770, respectively), whereas BWS progressed minimally (from κ=0.717 to κ=0.736) despite its basic classification. Parameter complexity influenced overall performance, with 62.5%, 50%, and 37.5% of trainees achieving competence for common, intermediate, and complex findings, respectively, and reaching expert-level proficiency after 75 to 112 examinations.