Red Dichromatic Imaging Improves the Recognition of Bleeding Points During Endoscopic Submucosal Dissection

Background Previous studies have indicated that red dichromatic imaging (RDI) improved the visibility of gastrointestinal bleeding. Aims To investigate the recognition of bleeding points during endoscopic submucosal dissection (ESD) under RDI compared with that under white light imaging (WLI). Methods Consecutive patients scheduled to undergo esophageal or gastric ESD at a single center were enrolled. Paired videos of active bleeding during ESD under WLI and RDI were created. Six endoscopists identified the virtual hemostasis point on still images after random video viewing. The distance between virtual hemostasis and actual bleeding points was scored in four levels (0–3 points), and the association with the color value was analyzed in both WLI and RDI. Results We evaluated 116 videos for 58 bleeding points. The median visibility score and recognition rate were significantly higher for RDI than for WLI (2.17 vs. 1.42, p < 0.001 and 62.1% vs 27.6%, p < 0.001). Additionally, the recognition rate of trainees in RDI was higher than that of experts in WLI (60.3% vs. 43.1%, p = 0.067). The median color difference of RDI was significantly higher than that of WLI (8.97 vs. 3.69, p < 0.001). Furthermore, the correlation coefficient between the visibility score and color difference was 0.712 (strong correlation). Conclusion RDI can provide better recognition of bleeding points than WLI during ESD. Therefore, further studies are warranted to investigate whether RDI improves ESD outcomes. Graphical Abstract