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P142 Second-generation colon capsule endoscopy (C2) is highly accurate to detect mucosal lesions: a prospective study in over 100 patients with ulcerative colitis

H. Y. Shi*, F. K. Chan, J. Y. Ching, A. Higashimori, H. Chan, K. Lam, A. Chan, J. Chan, R. Tang, J. C. Wu, J. J. Sung, S. C. Ng

The Chinese University of Hong Kong, Hong Kong, China


Capsule colonoscopy is a non-invasive imaging procedure to detect mucosal inflammation and polyps. We measured the accuracy of second-generation colon capsule endoscopy (C2) in identifying mucosal lesions and performed a satisfaction survey in patients with ulcerative colitis (UC).


In a prospective study, consecutive UC subjects underwent C2 followed by conventional colonoscopy (the reference) on the same day after standard bowel preparation from October 2014 to October 2015. Each segment of colon (right colon, proximal to hepatic flexure; transverse colon; and left colon, distal to splenic flexure) was scored using Mayo endoscopic sub-score. The endoscopist was blinded to the C2 results, and vice versa. Mucosal inflammation was defined as Mayo endoscopic subcore > 1. Histologic inflammation was defined as a Geboes score of > 2.0. Patients’ acceptance for each procedure was assessed on a scale from 0 (not acceptable at all) to 10 (fully acceptable).


Included were 101 UC patients (47.5% male; median age 50 years; range 18–71 years). C2 was excreted within 7.5 hours in 68.4% of patients. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of C2 in identifying mucosal inflammation was 93.1%, 84.4%, 40.3%, and 99.1%, respectively. Amongst the segments that showed inflammation on C2 but no inflammation on colonoscopy, 35.3% had histologic inflammation. The sensitivity, specificity, PPV, and NPV of C2 for detecting pseudopolyps/ ≥ 5 mm polyps were 87.9%, 70.0%, 61.7%, and 91.3%, respectively. Patients’ acceptance for C2 (median score [interquartile range, {IQR}: 8 [6–9]) was better compared with colonoscopy (median score [IQR]: 7 [5–8]) (p = 0.041). Of patients, 66.3% preferred C2, and 82.6% would accept another C2 examination.


In the first large-scale prospective study of C2 in patients with UC, we showed that C2 had high sensitivity and specificity. Because it is accurate and user-friendly, C2 performance is adequate as an alternative to colonoscopy for monitoring mucosal lesions in patients with UC.