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©The Author(s) 2019. Published by Baishideng Publishing Group Inc. All rights reserved.
Utility of linked color imaging for endoscopic diagnosis of early gastric cancer
Toshihisa Fujiyoshi, Ryoji Miyahara, Kohei Funasaka, Kazuhiro Furukawa, Tsunaki Sawada, Keiko Maeda, Takeshi Yamamura, Takuya Ishikawa, Eizaburo Ohno, Masanao Nakamura, Hiroki Kawashima, Masato Nakaguro, Masahiro Nakatochi, Yoshiki Hirooka
Toshihisa Fujiyoshi, Ryoji Miyahara, Kohei Funasaka, Kazuhiro Furukawa, Takuya Ishikawa, Eizaburo Ohno, Masanao Nakamura, Hiroki Kawashima, Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya 4668550, Japan
Tsunaki Sawada, Keiko Maeda, Takeshi Yamamura, Yoshiki Hirooka, Department of Endoscopy, Nagoya University Hospital, Nagoya 4668560, Japan
Masato Nakaguro, Department of Pathology and Laboratory Medicine, Nagoya University Hospital, Nagoya 4668560, Japan
Masahiro Nakatochi, Division of Data Science, Data Coordinating Center, Department of Advanced Medicine, Nagoya University Hospital, Nagoya 4668560, Japan
Author contributions: Fujiyoshi T and Miyahara R designed and performed the research; Fujiyoshi T, Nakaguro M and Nakatochi M analyzed the data. Fujiyoshi T and Miyahara R wrote the paper. Miyahara R, Funasaka K, Furukawa K, Sawada T, Maeda K, Yamamura T, Ishikawa T, Ohno E, Nakamura M and Kawashima H provided the critical review of the manuscript. Hirooka Y provided administrative support and supervised the study.
Institutional review board statement: The study was reviewed and approved by the Ethics Committee of Nagoya University Hospital.
Informed consent statement: All study participants provided informed written consent prior to study enrollment.
Conflict-of-interest statement: All authors declare no conflicts-of-interest related to this article.
Data sharing statement: No additional data are available.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Corresponding author: Ryoji Miyahara, MD, PhD, Associate Professor, Chief Doctor, Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 4668550, Japan. myhr@med.nagoya-u.ac.jp
Telephone: +81-52-7442172 Fax: +81-52-7442180
Received: December 31, 2018
Peer-review started: January 2, 2019
First decision: January 18, 2019
Revised: February 14, 2019
Accepted: February 15, 2019
Article in press: February 16, 2019
Published online: March 14, 2019
ARTICLE HIGHLIGHTS
Research background
Linked color imaging (LCI) emphasizes slight differences in the “red” color of the mucosa by image processing, including enhancement of differences in chroma and hue of the red mucosal color.
Research motivation
The utility of LCI for diagnosis of Helicobacter pylori gastritis has been well described, but there are few studies of LCI for diagnosis of gastrointestinal cancer and, to our knowledge, parallel analyses of LCI, white light imaging (WLI), and pathology samples have not been reported.
Research objectives
The objectives of this study are to evaluate the utility of LCI for endoscopic diagnosis of early gastric cancer and to examine if pathological findings can explain the changes in red shade in LCI.
Research methods
Three endoscopists evaluated lesion recognition with WLI and LCI. Color values in Commission Internationale de l'Eclairage (CIE) 1976 L*a*b* color space were used to calculate the color difference (ΔE) between cancer lesions and non-cancer areas. After endoscopic submucosal dissection, blood vessel density in the surface layer of the gastric epithelium was evaluated pathologically. The identical region of interest was selected for analyses of endoscopic images (WLI and LCI) and pathological analyses.
Research results
LCI gave better contrast than WLI for the color difference between cancer lesions and surrounding non-cancer tissue; an a* cutoff ≥ 24 for the value in CIE 1976 L*a*b* color space had good sensitivity and specificity for diagnosis of early gastric cancer; and surface blood vessel density in cancer lesions was significantly higher than that in non-cancer areas.
Research conclusions
LCI was useful for recognition of early gastric cancer lesions because this method provides good contrast in color differences between lesions and surrounding tissue. Blood vessel density from the surface to a depth of 350 μm was higher in cancer lesions than in non-cancer areas, and LCI clearly shows this feature as a change in redness.
Research perspectives
If these color values are evaluable in real time, artificial intelligence may permit automatic recognition and diagnosis of lesions.
