Artificial intelligence using a convolutional neural network for automatic detection of small-bowel angioectasia in capsule endoscopy images.

Tsuboi, Akiyoshi; Oka, Shiro; Aoyama, Kazuharu; Saito, Hiroaki; Aoki, Tomonori; Yamada, Atsuo; Matsuda, Tomoki; Fujishiro, Mitsuhiro; Ishihara, Soichiro; Nakahori, Masato; Koike, Kazuhiko; Tanaka, Shinji; Tada, Tomohiro

OBJECTIVES Although small-bowel angioectasia is reported as the most common cause of bleeding in patients and frequently diagnosed by capsule endoscopy (CE) in patients with obscure gastrointestinal bleeding, a computer-aided detection method has not been established. We developed an artificial intelligence system with deep learning that can automatically detect small-bowel angioectasia in CE images. METHODS We trained a deep convolutional neural network (CNN) system based on Single Shot Multibox Detector using 2,237 CE images of angioectasia. We assessed its diagnostic accuracy by calculating the area under the receiver operating characteristic curve (ROC-AUC), sensitivity, specificity, positive predictive value, and negative predictive value using an independent test set of 10,488 small-bowel images, including 488 images of small-bowel angioectasia. RESULTS The AUC to detect angioectasia was 0.998. The sensitivity, specificity, positive predictive value, and negative predictive value of CNN were 98.8%, 98.4%, 75.4%, and 99.9%, respectively, at a cut-off value of 0.36 for the probability score. CONCLUSIONS We developed and validated a new system based on CNN to automatically detect angioectasia in CE images. This may be well applicable to daily clinical practice to reduce the burden of physicians as well as to reduce oversight. This article is protected by copyright. All rights reserved.