Recognition accuracy of tumor extent using a prototype 3D endoscope for superficial gastric tumor: an ex vivo crossover study

Background and study aims  Many studies have shown the utility of rigid three-dimensional (3 D) endoscopes in surgery, but few have reported the utility of flexible 3 D endoscopes. This ex vivo study was intended to investigate whether a newly developed 3 D endoscope (GIF-Y0083; Olympus) improves diagnostic accuracy for superficial gastric tumor. Methods  Twelve observers comprising experts, trainees, and novices (4 each) evaluated 2 D and 3 D images of 20 specimens resected by gastric ESD. Evaluation items were diagnostic accuracy of tumor extent and degree of confidence in assessing (a) tumor extent, (b) morphology, and (c) comprehensive recognition. The 2 D and 3 D endoscopy data were compared in a crossover analysis. Results  Overall, diagnostic accuracy was significantly higher with 3 D images (88.1 %) than with 2 D images (84.2 %) ( P Conclusion  Compared with 2 D images, 3 D images significantly improved both diagnostic accuracy of tumor extent and degree of confidence for diagnosing superficial gastric tumor. The utility of the 3 D endoscope was apparent among trainees and novices and for the diagnosis of type IIc lesions.