Retrospective Study
Copyright ©The Author(s) 2019. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Mar 14, 2019; 25(10): 1248-1258
Published online Mar 14, 2019. doi: 10.3748/wjg.v25.i10.1248
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
Abstract
BACKGROUND

Linked color imaging (LCI) is a method of endoscopic imaging that emphasizes slight differences in red mucosal color.

AIM

To evaluate LCI in diagnostic endoscopy of early gastric cancer and to compare LCI and pathological findings.

METHODS

Endoscopic images were obtained for 39 patients (43 lesions) with early gastric cancer. Three endoscopists evaluated lesion recognition with white light imaging (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.

RESULTS

LCI was superior for lesion recognition (P < 0.0001), and ΔE between cancer and non-cancer areas was significantly greater with LCI than WLI (29.4 vs 18.6, P < 0.0001). Blood vessel density was significantly higher in cancer lesions (5.96% vs 4.15%, P = 0.0004). An a* cut-off of ≥ 24 in CIE 1976 L*a*b* color space identified a cancer lesion using LCI with sensitivity of 76.7%, specificity of 93.0%, and accuracy of 84.9%.

CONCLUSION

LCI is more effective for recognition of early gastric cancer compared to WLI as a result of improved visualization of changes in redness. Surface blood vessel density was significantly higher in cancer lesions, and this result is consistent with LCI image analysis.

Keywords: Linked color imaging, Early gastric cancer, Endoscopic submucosal dissection, Vessel density, Color difference

Core tip: This study showed the utility of linked color imaging (LCI) for screening endoscopy of early gastric cancer and the concordant change in blood vessel density with redness in LCI image. The key results of the study were as follows: LCI gave better contrast than white light imaging for the color difference between cancer lesions and surrounding non-cancer tissue; an a* cutoff ≥ 24 for the value in Commission Internationale de l'Eclairage 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.