Red dichromatic imaging improved the visibility of exposed blood vessels in gastric ulcer induced by endoscopic submucosal dissection– a pilot study

Abstract

Background One of the major complications of gastric endoscopic submucosal dissection (ESD) is delayed bleeding. The treatment of exposed vessels after completed dissection should be effective to avoid delayed bleeding. However, it’s sometimes difficult to detect the detection of exposed blood vessels on ulcers induced by ESD. A recent study reported that red dichromatic imaging (RDI) was useful for detecting exposed vessels. In this study, we aimed to measure the visibility of exposed vessels and the quantitative color difference between the exposed vessels and surrounding tissue on ulcers, as observed using RDI after completed dissection. Methods Sixty-four vessels (14 patients) in gastric ESD-induced ulcers were evaluated using both white light imaging (WLI) and RDI. The Commission Internationale de l’Eclairage 1976 (L*a*b*) color space was used to measure the color difference. The color difference was evaluated by comparing the color values of regions of interest for the point of an exposed vessel and three points surrounding an exposed vessel. The visibility of exposed vessels was evaluated using a visibility scoring system. The primary endpoint was color differences (ΔE) between the exposed vessels and surrounding tissue in each modality. Results The average ΔE values (± SEM) for WLI and RDI were 24.85 (± 1.19) and 31.83(± 1.31), respectively. The ΔE value for RDI was significantly higher than that for WLI (p < 0.01). The visibility score was improved in 54.7% (35/64) of cases. Conclusions The color differences between the exposed vessels and surrounding tissue on gastric ESD-induced ulcers were higher with RDI than with WLI, and RDI improved the visibility of exposed vessels.