title: Accuracy of computer-aided diagnosis based on narrow-band imaging endocytoscopy for diagnosing colorectal lesions: comparison with experts.
abstract: OBJECTIVE
  Real-time characterization of colorectal lesions during colonoscopy is important for reducing medical costs, given that the need for a pathological diagnosis can be omitted if the accuracy of the diagnostic modality is sufficiently high. However, it is sometimes difficult for community-based gastroenterologists to achieve the required level of diagnostic accuracy. In this regard, we developed a computer-aided diagnosis (CAD) system based on endocytoscopy (EC) to evaluate cellular, glandular, and vessel structure atypia in vivo. The purpose of this study was to compare the diagnostic ability and efficacy of this CAD system with the performances of human expert and trainee endoscopists.
  
  
  METHODS
  We developed a CAD system based on EC with narrow-band imaging that allowed microvascular evaluation without dye (ECV-CAD). The CAD algorithm was programmed based on texture analysis and provided a two-class diagnosis of neoplastic or non-neoplastic, with probabilities. We validated the diagnostic ability of the ECV-CAD system using 173 randomly selected EC images (49 non-neoplasms, 124 neoplasms). The images were evaluated by the CAD and by four expert endoscopists and three trainees. The diagnostic accuracies for distinguishing between neoplasms and non-neoplasms were calculated.
  
  
  RESULTS
  ECV-CAD had higher overall diagnostic accuracy than trainees (87.8 vs 63.4%; [Formula: see text]), but similar to experts (87.8 vs 84.2%; [Formula: see text]). With regard to high-confidence cases, the overall accuracy of ECV-CAD was also higher than trainees (93.5 vs 71.7%; [Formula: see text]) and comparable to experts (93.5 vs 90.8%; [Formula: see text]).
  
  
  CONCLUSIONS
  ECV-CAD showed better diagnostic accuracy than trainee endoscopists and was comparable to that of experts. ECV-CAD could thus be a powerful decision-making tool for less-experienced endoscopists.
authors.affiliation: Digestive Disease Center, Showa University, Northern Yokohama Hospital, 35-1 Chigasaki-chuo, Tsuzuki, Yokohama, 224-8503, Japan. mmisawa@med.showa-u.ac.jp.
authors.forename: Masashi
authors.identifier: http://orcid.org/0000-0002-8520-2036
authors.initials: M
authors.lastname: Misawa
authors.affiliation: Digestive Disease Center, Showa University, Northern Yokohama Hospital, 35-1 Chigasaki-chuo, Tsuzuki, Yokohama, 224-8503, Japan.
authors.forename: Shin-Ei
authors.initials: SE
authors.lastname: Kudo
authors.affiliation: Digestive Disease Center, Showa University, Northern Yokohama Hospital, 35-1 Chigasaki-chuo, Tsuzuki, Yokohama, 224-8503, Japan.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Mori
authors.affiliation: Digestive Disease Center, Showa University, Northern Yokohama Hospital, 35-1 Chigasaki-chuo, Tsuzuki, Yokohama, 224-8503, Japan.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Takeda
authors.affiliation: Digestive Disease Center, Showa University, Northern Yokohama Hospital, 35-1 Chigasaki-chuo, Tsuzuki, Yokohama, 224-8503, Japan.
authors.forename: Yasuharu
authors.initials: Y
authors.lastname: Maeda
authors.affiliation: Digestive Disease Center, Showa University, Northern Yokohama Hospital, 35-1 Chigasaki-chuo, Tsuzuki, Yokohama, 224-8503, Japan.
authors.forename: Shinichi
authors.initials: S
authors.lastname: Kataoka
authors.affiliation: Digestive Disease Center, Showa University, Northern Yokohama Hospital, 35-1 Chigasaki-chuo, Tsuzuki, Yokohama, 224-8503, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Nakamura
authors.affiliation: Digestive Disease Center, Showa University, Northern Yokohama Hospital, 35-1 Chigasaki-chuo, Tsuzuki, Yokohama, 224-8503, Japan.
authors.forename: Toyoki
authors.initials: T
authors.lastname: Kudo
authors.affiliation: Digestive Disease Center, Showa University, Northern Yokohama Hospital, 35-1 Chigasaki-chuo, Tsuzuki, Yokohama, 224-8503, Japan.
authors.forename: Kunihiko
authors.initials: K
authors.lastname: Wakamura
authors.affiliation: Digestive Disease Center, Showa University, Northern Yokohama Hospital, 35-1 Chigasaki-chuo, Tsuzuki, Yokohama, 224-8503, Japan.
authors.forename: Takemasa
authors.initials: T
authors.lastname: Hayashi
authors.affiliation: Digestive Disease Center, Showa University, Northern Yokohama Hospital, 35-1 Chigasaki-chuo, Tsuzuki, Yokohama, 224-8503, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Katagiri
authors.affiliation: Digestive Disease Center, Showa University, Northern Yokohama Hospital, 35-1 Chigasaki-chuo, Tsuzuki, Yokohama, 224-8503, Japan.
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Baba
authors.affiliation: Digestive Disease Center, Showa University, Northern Yokohama Hospital, 35-1 Chigasaki-chuo, Tsuzuki, Yokohama, 224-8503, Japan.
authors.forename: Fumio
authors.initials: F
authors.lastname: Ishida
authors.affiliation: Digestive Disease Center, Showa University, Koto-Toyosu Hospital, Tokyo, Japan.
authors.forename: Haruhiro
authors.initials: H
authors.lastname: Inoue
authors.affiliation: Locus Logic, Inc., Nagoya, Japan.
authors.forename: Yukitaka
authors.initials: Y
authors.lastname: Nimura
authors.affiliation: Graduate School of Information Science, Nagoya University, Nagoya, Japan.
authors.forename: Msahiro
authors.initials: M
authors.lastname: Oda
authors.affiliation: Information and Communications, Nagoya University, Nagoya, Japan.
authors.forename: Kensaku
authors.initials: K
authors.lastname: Mori
mesh_terms: D000368:Aged; D000465:Algorithms; D003111:Colonic Polyps / Q000000981:diagnostic imaging*; D003113:Colonoscopy / Q000379:methods*; D015179:Colorectal Neoplasms / Q000000981:diagnostic imaging*; D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D004724:Endoscopy / Q000379:methods*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D062048:Narrow Band Imaging; D010363:Pattern Recognition, Automated; D011336:Probability; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012984:Software; D016896:Treatment Outcome
keywords: Colon polyp; Colonoscopy; Computer-aided diagnosis; Endocytoscopy; Magnifying endoscopy; Narrow-band imaging