S940 Endoscopic Ultrasound for Diagnosis and Management of Inflammatory Bowel Disease

Abstract

Introduction: Distinguishing Crohn’s disease (CD) from ulcerative colitis (UC) may be difficult when the disease is limited to the colon. The aim of this study was to examine the role of endoscopic ultrasound (EUS) in diagnosing CD versus UC and in monitoring disease activity. Methods: Adults with CD with colonic involvement, with UC, and controls who were undergoing colonoscopy to evaluate gastrointestinal symptoms or screen for colon cancer from 2019-2021 at a tertiary care center were prospectively recruited. Patients with active colorectal cancer, infectious colitis, diverticulitis, or microscopic colitis were excluded. Measurements of wall layer thickness from the cecum and rectum were obtained using the through-the-scope miniprobe ultrasound device (Olympus UM-3R-3). Active disease was defined as Mayo Clinic endoscopic subscore ≥1 for UC and SES-CD score >3 for CD. Statistical analyses included the ANOVA test, sensitivity (Se), and specificity (Sp) with 95% confidence interval. Results: Sixty patients were included in the study: 20 with CD, 20 with UC, and 20 controls. 60% of patients were females with an average age of 43 years. CD and UC patients with active rectal inflammation had a thicker rectal total colon wall compared to controls (4.1 and 3.2 vs. 2.1 mm respectively, P < 0.01). Patients with active CD had a thicker rectal submucosa compared to active UC (1.8 vs. 0.6 mm, P < 0.01). Those with active UC had a thicker rectal mucosa compared to active CD (1.4 vs. 0.9 mm, P = 0.01) (Table 1). Patients with active CD had thicker rectal submucosa and total colon wall compared to those with inactive CD (submucosa: 1.8 vs. 0.8, total wall: 4.1 vs. 2.4 mm, P < 0.01). Similar findings were also observed in the cecum. Patients with active UC had thicker rectal mucosa and total colon wall compared to those with inactive UC (mucosa: 1.4 vs. 0.7, total wall: 3.2 vs. 2.3 mm, P < 0.01). A cut-off value of 1 mm submucosal thickness for CD and 1 mm mucosal thickness for UC could accurately differentiate between active and inactive disease for both conditions (Se 100% [66, 100], Sp 91% [59, 100] and Se 90% [56, 100], Sp 80% [44, 97], respectively) (Figure 1). Conclusion: EUS measurements of colon wall layers can help distinguish CD versus UC when the inflammation is limited to the colon. In addition, patients with active CD and UC have a significantly thicker submucosa and mucosa, respectively, compared to those with inactive disease. EUS is a potentially useful tool to diagnose and manage IBD.Table 1.: Rectal Wall Thickness (in mm) for Active CD, UC, and ControlFigure 1.: Rectal Mucosa and Submucosa Thickness in Crohn's Disease, Ulcerative Colitis, and Controls.