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.

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.

Secure intravariceal sclerotherapy with red dichromatic imaging decreases the recurrence rate of esophageal varices: A propensity score matching analysis

BACKGROUND

Red dichromatic imaging (RDI) is next-generation image-enhanced endoscopy technique released in July 2020. We previously reported that RDI can predict esophageal varices (EV) depth and decrease their recurrence rate by accurate intravariceal injections during endoscopic injection sclerotherapy (EIS) using unreleased prototype RDI endoscope. In this study, we analyzed whether RDI improves the overall survival (OS) rate and whether it is more accurate independent predictor of EV recurrence than white light imaging (WLI), using propensity score matching.

METHODS

A total of 179 patients were enrolled. Patients were matched for age, platelet count, liver function, EV size, luminal diameter, and EV depth using propensity score matching, and 78 patients (RDI, 39; WLI, 39) were finally matched. Primary endpoints were OS and recurrence rates. Secondary endpoints were success rate of intravariceal injection, operating time, incidence of adverse events (AEs), and predictors associated with OS and recurrence rates.

RESULTS

There was no difference in OS (P = .193), but the cumulative recurrence rate in the RDI group was significantly lower than in the WLI group (P = .002). Success rates of intrainjection, operating time, and incidence of AEs were better in the RDI group (p = 0.035, .026, and .0019, respectively). Independent predictors associated with recurrence rate by Cox proportional regression were RDI function and luminal diameter (P < .001 and .017, respectively).

CONCLUSION

RDI did not improve OS but decreased the recurrence rate. Independent predictors of recurrence rate were RDI and luminal diameter, resulting from secure intravariceal injections in EIS.

Fundamentals, Diagnostic Capabilities and Perspective of Narrow Band Imaging for Early Gastric Cancer

The development of image-enhanced endoscopy has dramatically improved the qualitative and quantitative diagnosis of gastrointestinal tumors. In particular, narrow band imaging (NBI) has been widely accepted by endoscopists around the world in their daily practice. In 2009, Yao et al. proposed vessel plus surface (VS) classification, a diagnostic algorithm for early gastric cancer using magnifying endoscopy with NBI (ME-NBI), and in 2016, Muto et al. proposed a magnifying endoscopy simple diagnostic algorithm for early gastric cancer (MESDA-G) based on VS classification. In addition, the usefulness of ME-NBI in the differential diagnosis of gastric cancer from gastritis, diagnosis of lesion extent, inference of histopathological type, and diagnosis of depth has also been investigated. In this paper, we narrative review the basic principles, current status, and future prospects of NBI.

Recent advancements in image-enhanced endoscopy in the pancreatobiliary field

Image-enhanced endoscopy (IEE) has advanced gastrointestinal disease diagnosis and treatment. Traditional white-light imaging has limitations in detecting all gastrointestinal diseases, prompting the development of IEE. In this review, we explore the utility of IEE, including texture and color enhancement imaging and red dichromatic imaging, in pancreatobiliary (PB) diseases. IEE includes methods such as chromoendoscopy, optical-digital, and digital methods. Chromoendoscopy, using dyes such as indigo carmine, aids in delineating lesions and structures, including pancreato-/cholangio-jejunal anastomoses. Optical-digital methods such as narrow-band imaging enhance mucosal details and vessel patterns, aiding in ampullary tumor evaluation and peroral cholangioscopy. Moreover, red dichromatic imaging with its specific color allocation, improves the visibility of thick blood vessels in deeper tissues and enhances bleeding points with different colors and see-through effects, proving beneficial in managing bleeding complications post-endoscopic sphincterotomy. Color enhancement imaging, a novel digital method, enhances tissue texture, brightness, and color, improving visualization of PB structures, such as PB orifices, anastomotic sites, ampullary tumors, and intraductal PB lesions. Advancements in IEE hold substantial potential in improving the accuracy of PB disease diagnosis and treatment. These innovative techniques offer advantages paving the way for enhanced clinical management of PB diseases. Further research is warranted to establish their standard clinical utility and explore new frontiers in PB disease management.

Identification of bleeding points after bile duct biopsy using red dichromatic imaging during peroral cholangioscopy: A case report

Red dichromatic imaging is a new image-enhancement technology that clarifies the differences in blood concentrations and improves the visibility of the bleeding point. A 71-year-old man was presented with a common bile duct stone, which was completely removed using electrohydraulic shock wave lithotripsy with peroral cholangioscopy. During peroral cholangioscopy, a nodular lesion was found at the confluence of the cystic duct, and a forceps biopsy was performed. It was difficult to confirm the bleeding point using white-light imaging because of the pooling of blood. After switching to red dichromatic imaging mode 2 and washing the bile duct with saline solution, the bleeding point was observed in darker yellow than the surrounding blood, allowing the identification of the bleeding point. Red dichromatic imaging can be used in the future to maintain hemostasis during peroral cholangioscopy.

Direct peroral cholangioscopy with red dichromatic imaging 3 detected the perihilar margin of superficial papillary extension in a patient with intraductal papillary neoplasm of the bile duct

Intraductal papillary neoplasms of the bile duct (IPNB) are a tumor derived from bile duct epithelium that tends to spread laterally and non‐invasively. Surgery is the first‐choice treatment for IPNB. It is extremely important to accurately diagnose the extent of lateral tumor extension. Although peroral cholangioscopy (POCS) is a potentially useful modality for detecting tumor range with direct observation, poor image quality is a limitation of POCS. Recently, a new‐generation endoscopy system (EVIS X1) was equipped with functions such as red dichromatic imaging to improve image quality. A 75‐year‐old man with cholangitis was referred to our department. Various imaging studies showed a mass in the middle to lower bile duct and dilatation of the common bile duct and the intrahepatic bile duct. Endoscopic retrograde cholangiopancreatography was performed. A biopsy of the main tumor in the lower common bile duct revealed IPNB. It was difficult to determine the extent of superficial tumor extension with modalities such as contrast‐enhanced computed tomography, magnetic resonance imaging, and endoscopic ultrasonography but the detailed evaluation was possible using POCS with red dichromatic imaging 3. The patient underwent hepatopancreatoduodenectomy. This case suggests the usefulness of direct observation using POCS with red dichromatic imaging 3 to determine the range of IPNB.