Effectiveness of red dichromatic imaging for dissection of the submucosal layer when hematoma is encountered

Development and clinical usefulness of a unique red dichromatic imaging technology in gastrointestinal endoscopy: A narrative review

Image-enhanced endoscopy (IEE) allows real-time high-contrast imaging of a targeted lesion without any special equipment. Among various IEE technologies, narrow-band imaging, in which a light of shorter wavelength is used, emphasizes the surface and blood vessel patterns on the mucosal surface. This technology has been widely used in endoscopic diagnosis in the gastrointestinal tract. Red dichromatic imaging (RDI) was recently developed; it utilizes lights of longer wavelengths (520-550, 595-610, and 620-640 nm), which have weak light scattering characteristics in contrast to narrow-band imaging. RDI was designed to enhance the visibility of deep-lying blood vessels and areas of bleeding, and it has been installed in the latest Olympus endoscopy system, EVIS X1, as an advanced version of the optical-digital method that was originally developed. Improving the visibility of deep blood vessels allows more accurate evaluation of esophageal varices and the degree of inflammation in ulcerative colitis. Easier identification of a bleeding source makes hemostasis quicker and easier to accomplish during endoscopic resection procedures such as endoscopic submucosal dissection and peroral endoscopic myotomy as well as during treatment of gastrointestinal bleeding from a peptide ulcer or colon diverticulum. The authors herein review the technological development and principles, review the existing literature on RDI, and discuss the utility and effectiveness of this unique IEE technology in gastrointestinal endoscopy.

Red dichromatic imaging reduces endoscopic treatment time of esophageal varices by increasing bleeding point visibility (with video)

BACKGROUND

Red dichromatic imaging (RDI) is a novel image-enhanced endoscopy released in 2020, which increases the visibility of deeper vessels. In this study, we retrospectively investigated whether RDI can shorten treatment times of endoscopic injection sclerotherapy (EIS), and which operational procedure times are affected compared with white light imaging (WLI).

METHODS

A total of 155 patients (RDI, 70; WLI, 85) with risky esophageal varices (EV), who were treated with EIS were analyzed. Treatment times were compared, and predictors associated with treatment time were analyzed by multivariate analysis. For 24 cases (RDI, 12; WLI, 12) in which treatment videos were recorded, the procedure times of each step (observation of EV, needle flush, positioning, puncture, observation of bleeding, hemostasis, observation after hemostasis) were measured. Regarding the seven patients with EV bleeding, color differences were calculated between the bleeding point and the blood pool using the CIE (L*a*b*) color measurement method, and results were compared between using RDI and WLI.

RESULTS

Treatment times were shorter in the RDI group (RDI vs. WLI = 35.1 vs. 42.2 min; P < 0.01). 'RDI function' and 'amount of sclerosant' were extracted as independent predictors of treatment time. Times for 'observation of EV' and 'observation of bleeding' were shorter in the RDI group (P = 0.01 and <0.01, respectively). Regarding the color difference, RDI significantly increased bleeding point visibility (RDI vs. WLI = 31.4 ± 11.8 vs. 8.6 ± 6.2, P < 0.001).

CONCLUSION

Red dichromatic imaging can shorten the treatment time of EIS by increasing bleeding point visibility.

Clinical usefulness of red dichromatic imaging in hemostatic treatment during endoscopic submucosal dissection: First report from a multicenter, open-label, randomized controlled trial

OBJECTIVES

To verify the efficacy and safety of red dichromatic imaging (RDI) in hemostatic procedures during endoscopic submucosal dissection (ESD).

METHODS

This is a multicenter randomized controlled trial of 404 patients who underwent ESD of the esophagus, stomach, colorectum. Patients who received hemostatic treatments by RDI during ESD were defined as the RDI group (n = 204), and those who received hemostatic treatments by white light imaging (WLI) were defined as the WLI group (n = 200). The primary endpoint was a shortening of the hemostasis time. The secondary endpoints were a reduction of the psychological stress experienced by the endoscopist during the hemostatic treatment, a shortened treatment time, and a non-inferior perforation rate, in RDI versus WLI.

RESULTS

The mean hemostasis time in RDI (n = 860) was not significantly shorter than that in WLI (n = 1049) (62.3 ± 108.1 vs. 56.2 ± 74.6 s; P = 0.921). The median hemostasis time was significantly longer in RDI than in WLI (36.0 [18.0-71.0] vs. 28.0 [14.0-66.0] s; P = 0.001) in a sensitivity analysis. The psychological stress was significantly lower in RDI than in WLI (1.71 ± 0.935 vs. 2.03 ± 1.038; P < 0.001). There was no significant difference in the ESD treatment time between RDI (n = 161) and WLI (n = 168) (58.0 [35.0-86.0] vs. 60.0 [38.0-88.5] min; P = 0.855). Four perforations were observed, but none of them took place during the hemostatic treatment.

CONCLUSIONS

Hemostatic treatment using RDI does not shorten the hemostasis time. RDI, however, is safe to use for hemostatic procedures and reduces the psychological stress experienced by endoscopists when they perform hemostatic treatment during ESD. UMIN000025134.

Endoscopic submucosal dissection and tunneling procedures using novel image-enhanced technique

Background and Aims

Recent innovations in image-enhanced endoscopy allow early detection and management of GI lesions. In this study, we aim to analyze the utility of texture and color enhancement imaging (TXI) and red dichromatic imaging (RDI) during endoscopic submucosal dissection (ESD) and submucosal tunneling procedures.

Methods

Patients who underwent ESD, submucosal tunneling endoscopic resection, and peroral endoscopic myotomy (POEM) using the novel imaging technique including TXI and RDI were included in the study.

Results

Twenty-five patients (13 male; age 43 ± 15.69 years) underwent POEM for achalasia (n = 20), submucosal tunneling endoscopic resection for esophageal subepithelial lesions (n = 3), and ESD for gastric neuroendocrine tumors (n = 2). All of the procedures were successfully performed. Mean procedure duration was 55.52 ± 21.61 minutes. TXI mode was used in all the cases, whereas RDI mode was used on 15 occasions. While using RDI mode, hemostasis was achieved in 1 attempt on 12 (80%) occasions. The site of mucosal incision was revised in 3 cases during POEM based on TXI and RDI modes.

Conclusions

Submucosal tunneling and endoscopic dissection procedures can be conveniently performed using a new image-enhanced technique. RDI is useful in localizing the site of bleeding during endoscopic dissection.