Differentiation of Active Ulcerative Colitis vs Noninflammatory Bowel Disease Proctitis by Transperineal Superb Microvascular Imaging

Abstract Background Transabdominal ultrasonography and transperineal ultrasonography (TPUS) appear correspond to colonoscopy (CS) for evaluating ulcerative colitis (UC) activity, but their utility in UC diagnosis remains unclear. This research compared the accuracy of TPUS and CS for assessing rectal activity and differentiating noninflammatory bowel disease proctitis from UC in pediatric cases. Methods The study is a blinded, prospective, and controlled trial. Prospectively, values of fecal calprotectin (FCP) and findings of the TPUS and CS were compared between child cases of UC and non-IBD proctitis. Findings of rectal wall thickening (RWT), rectal wall flow (RWF) on power Doppler, and microvascular signal at wall circumference (MSWC) on monochrome superb microvascular imaging assessed using TPUS were compared with the CS. Results Thirty patients with Mayo endoscopic subscore (MES) 0 to 1 UC, 57 with MES 2 to 3 UC, and 44 with proctitis were registered. Fecal calprotectin, RWF, and MSWC indicated significant differences among the groups (P < .05). Rectal wall thickening showed no significant difference between MES 0–1 and proctitis (P = .76). Rectal wall thickening and MSWC were independent predictors of endoscopic activity of UC, resulting in a sensitivity and specificity of 100% for RWT ≥4.5 mm and positive MSWC. Fecal calprotectin and RWF were independent predictors for differentiating MES 0 to 1 and proctitis, and FCP and RWT were independent predictors for differentiating MES 2 to 3 and proctitis. Sensitivity and specificity were 77.2% and 80.9%, respectively, for FCP >242.5 μg/g and RWF negative; and they were both 100% for RWT >4.1 mm and MSWC positive. Conclusions Transperineal ultrasonography with mSMI may enable the evaluation of rectal activity and differentiation of UC from non-IBD proctitis with accuracy comparable to endoscopy. Lay Summary Transperineal ultrasonography with superb microvascular imaging can differentiate ulcerative colitis from noninflammatory bowel disease proctitis and is therefore useful in distinguishing whether diarrhea and bloody stool during the treatments of ulcerative colitis are due to recurrence or infection.