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.
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.
ECV-CAD had higher overall diagnostic accuracy than trainees (87.8 vs 63.4%; \(P=0.01\)), but similar to experts (87.8 vs 84.2%; \(P=0.76\)). With regard to high-confidence cases, the overall accuracy of ECV-CAD was also higher than trainees (93.5 vs 71.7%; \(P<0.001\)) and comparable to experts (93.5 vs 90.8%; \(P=0.38\)).
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.
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Sessile serrated adenoma/polyp
CAD system for endocytoscopic vascular pattern
Negative predictive value
Positive predictive value
Support vector machine
American Society for Gastrointestinal Endoscopy
Preservation and Incorporation of Valuable Endoscopic Innovations
Region of interest
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This study was funded by grants from JSPS KAKENHI (Grant Numbers 25860564 and 15K19351). We would like to express our gratitude to Mr. Takashi Wakisaka and Mr. Hideo Kahara (Cybernet Systems Co., Ltd.).
Conflict of interest
K Mori received research funding from Cybernet System Company and Olympus Company. H Inoue received a lecture fee from Olympus Company. The other authors declare no conflicts of interest.
Informed consent was obtained from all study participants, and the study was approved by the Ethical Committee of Showa University (No. 1507-08). All procedures performed in this study involving human participants were in accordance with the ethical standards of the Ethical Committee of Showa University and with the 1964 Helsinki Declaration and its later amendments.
Japan patent JP 2015-036771 (patent pending) and JP 2015-200803 (patent pending).
The results of this study were presented at JAMIT 2015, Kanazawa, and UEGweek 2016, Vienna.
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Misawa, M., Kudo, S., Mori, Y. et al. Accuracy of computer-aided diagnosis based on narrow-band imaging endocytoscopy for diagnosing colorectal lesions: comparison with experts. Int J CARS 12, 757–766 (2017) doi:10.1007/s11548-017-1542-4
- Narrow-band imaging
- Computer-aided diagnosis
- Magnifying endoscopy
- Colon polyp