Case Report
Copyright ©The Author(s) 2021. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastrointest Endosc. Jul 16, 2021; 13(7): 233-237
Published online Jul 16, 2021. doi: 10.4253/wjge.v13.i7.233
Visibility of the bleeding point in acute rectal hemorrhagic ulcer using red dichromatic imaging: A case report
Yuichiro Hirai, Atsuto Kayashima, Yoshihiro Nakazato, Ai Fujimoto
Yuichiro Hirai, Atsuto Kayashima, Yoshihiro Nakazato, Ai Fujimoto, Department of Gastroenterology, National Hospital Organization Tokyo Medical Center, Tokyo 1520021, Japan
Author contributions: Fujimoto A was involved in conceptualization, revision and final approval; Hirai Y carried out investigation, data curation, writing original draft and editing the figures; Kayashima A was involved in performing the endoscopic hemostasis with the patient's consent; all authors have read and approved the final manuscript.
Informed consent statement: Informed consent was obtained from the patient’s son.
Conflict-of-interest statement: All the authors declare no conflicts of interest associated with this manuscript. The prototype endoscope (GIF-Y0058) was provided free of charge by Olympus Corporation, Tokyo, Japan.
CARE Checklist (2016) statement: The authors have read the CARE Checklist (2016), and the manuscript was prepared and revised according to the CARE Checklist (2016).
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (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:
Corresponding author: Ai Fujimoto, MD, PhD, Staff Physician, Department of Gastroenterology, National Hospital Organization Tokyo Medical Center, 2-5-1 Higashigaoka, Meguro-ku, Tokyo 1528902, Japan.
Received: December 18, 2020
Peer-review started: December 18, 2020
First decision: December 31, 2020
Revised: January 14, 2021
Accepted: June 25, 2021
Article in press: June 25, 2021
Published online: July 16, 2021

Red dichromatic imaging (RDI) is a novel image-enhanced endoscopy expected to improve the visibility of the bleeding point. However, it has not been thoroughly investigated.


A 91-year-old man developed a sudden massive hematochezia and underwent emergent colonoscopy. An ulcer with pulsatile bleeding was found on the lower rectum. Due to massive bleeding, the exact location of the bleeding point was not easy to detect with white light imaging (WLI). Upon switching to RDI, the bleeding point appeared in deeper yellow compared to the surrounding blood. Thus, RDI enabled us for easier recognition of the bleeding point, and hemostasis was achieved successfully. Furthermore, we reviewed endoscopic images and evaluated the color difference between the bleeding point and surrounding blood for WLI and RDI. In our case, the color difference of RDI was greater than that of WLI (9. 75 vs 6. 61), and RDI showed a better distinguished bleeding point from the surrounding blood.


RDI may improve visualization of the bleeding point by providing better contrast in color difference relative to surrounding blood.

Keywords: Red dichromatic imaging, Image-enhanced endoscopy, Acute hemorrhagic rectal ulcer, Gastrointestinal hemorrhage, Endoscopic hemostasis, Case report

Core Tip: Red dichromatic imaging (RDI) is a novel image-enhanced endoscopy presumed to improve the visibility of the bleeding point but has not yet been fully explored. We present a case in which RDI effectively identified the bleeding point in an acute hemorrhagic rectal ulcer lesion with an analysis of color difference compared to white light imaging. RDI may enable easier recognition of the bleeding point by enhancing the color contrast of the bleeding point relative to the surrounding blood.