Blue Laser Imaging, Blue Light Imaging, and Linked Color Imaging for the Detection and Characterization of Colorectal Tumors

The Interpretation of Magnifying Endoscopy for the Diagnosis of Colorectal Lesions

BACKGROUND

Accurate endoscopic diagnosis is crucial for determining the appropriate treatment strategy for colorectal lesions, which may include cold snare polypectomy, endoscopic mucosal resection, or endoscopic submucosal dissection.

SUMMARY

While white light imaging (WLI) serves as the basic and initial method for endoscopic diagnosis, additional techniques such as narrow band imaging (NBI), blue laser/light imaging (BLI), and magnified observation of pit patterns are necessary when WLI results are inconclusive. These advanced diagnostic methods enable precise differentiation of lesions such as adenoma, T1 cancer, and sessile serrated lesion. Furthermore, recent advancements in endoscopic systems have enhanced image clarity and detail, thereby improving diagnostic accuracy.

KEY MESSAGES

This review provides an in-depth discussion on how magnified endoscopy, utilizing the Japan NBI Expert Team (JNET) classification with NBI/BLI and pit pattern classification with chromoendoscopy, aids in the accurate diagnosis of colorectal lesions.

Linked Color Imaging with Light-Emitting Diode Light Enhances the Visibility of Gastric Neoplasm: A Prospective, Multicenter, Comparative Trial

BACKGROUND

Early detection of gastric cancer can play a key role in improving prognosis. Recently, light-emitting diodes (LED) have been developed as novel endoscopic systems. However, the differences in the visibility of gastric neoplastic lesions between LED and laser endoscopy remains unclear. We conducted a prospective multicenter trial to evaluate the non-inferiority of LED endoscopy in the visibility of gastric neoplastic lesions undergoing endoscopic submucosal dissection (ESD) in comparison to laser endoscopy.

METHODS

A multicenter, prospective, cross-sectional study was conducted in patients undergoing ESD for gastric neoplastic lesions at five hospitals throughout Japan. Seventy patients with 74 lesions were included in this study. The primary endpoint was the non-inferiority of the difference in the individual scores of linked color imaging (LCI) and white-light imaging (WLI) for LED and laser endoscopy for gastric neoplastic lesions.

RESULTS

The mean individual score was 2.66 ± 1.02, 3.17 ± 0.83, 2.75 ± 1.05, and 3.21 ± 0.84 in LED-WLI, LED-LCI, laser-WLI, and laser-LCI, respectively. The difference in individual scores of LCI and WLI was 0.51 ± 0.77 and 0.46 ± 0.80 in LED and laser endoscopy, respectively. The mean difference between LED and laser endoscopy was 0.04 (95% confidence interval [CI]: - 0.05 to 0.13, P < 0.001).

CONCLUSIONS

This study revealed the non-inferiority of the differences in individual scores between LCI and WLI in the comparison of LED and laser endoscopy for gastric neoplastic lesions.

Linked color imaging and upper gastrointestinal neoplasia

White light imaging (WLI) can sometimes miss early upper gastrointestinal (UGI) neoplasms, particularly minimal changes and flat lesions. Moreover, endoscopic diagnosis of UGI neoplasia is strongly influenced by the condition of the surrounding mucosa. Recently, image-enhanced endoscopy techniques have been developed and used in clinical practice; one of which is linked color imaging (LCI), which has an expanded color range for better recognition of slight differences in mucosal color and enables easy diagnosis and differentiation of noncancerous mucosa from carcinoma. LCI does not require magnified observation and can clearly visualize structures using an ultrathin scope; therefore, it is useful for screening and surveillance endoscopy. LCI is particularly useful for detecting gastric cancer after Helicobacter pylori eradication, which accounts for most gastric cancers currently discovered, and displays malignant areas in orange or orange-red surrounded by intestinal metaplasia in lavender. Data on the use of convolutional neural network and computer-aided diagnosis with LCI for UGI neoplasm detection are currently being collected. Further studies are needed to determine the clinical role of LCI and whether it can replace WLI.

The Comparison of Diagnostic Ability between Blue Laser/Light Imaging and Narrowband Imaging for Sessile Serrated Lesions with or without Dysplasia

Objectives

Diagnostic ability of sessile serrated lesions (SSL) and SSL with dysplasia (SSLD) using blue laser/light imaging (BLI) has not been well examined. We analyzed the diagnostic accuracy of BLI for SSL and SSLD using several endoscopic findings compared to those of narrow band imaging (NBI).

Materials and Methods

This was a subgroup analysis of prospective studies. 476 suspiciously serrated lesions of ≥2 mm on the proximal colon showing serrated change with magnified NBI or BLI in our institution between 2014 and 2021 were examined histopathologically. After propensity score matching, we evaluated the diagnostic ability of SSL and SSLD of the NBI and BLI groups regarding various endoscopic findings. For WLI findings, granule, depression, and reddish were examined for diagnosing SSLD. For NBI/BLI findings, expanded crypt opening (ECO) or thick and branched vessels (TBV) were examined for diagnosing SSL. Network vessels (NV) and white dendritic change (WDC) defined originally were examined for diagnosing SSLD.

Results

Among matched 176 lesions, the sensitivity of lesions with either ECO or TBV for SSL in the NBI/BLI group was 97.5%/98.5% (p = 0.668). Those with either WDC or NV for diagnosing SSLD in the groups were 81.0%/88.9% (p = 0.667). Regarding the rates of endoscopic findings among 30 SSLD and 290 SSL, there were significant differences in WDC (66.4% vs. 8.6%, p < 0.001), NV (55.3% vs. 1.4%, p < 0.001), and either WDC or NV (86.8% vs. 9.0%, p < 0.001).

Conclusions

The diagnostic ability of BLI for SSL and SSLD was not different from NBI. NV and WDC were useful for diagnosing SSLD.

Detailed Superiority of the CAD EYE Artificial Intelligence System over Endoscopists for Lesion Detection and Characterization Using Unique Movie Sets

Objectives

Detailed superiority of CAD EYE (Fujifilm, Tokyo, Japan), an artificial intelligence for polyp detection/diagnosis, compared to endoscopists is not well examined. We examined endoscopist's ability using movie sets of colorectal lesions which were detected and diagnosed by CAD EYE accurately.

Methods

Consecutive lesions of ≤10 mm were examined live by CAD EYE from March-June 2022 in our institution. Short unique movie sets of each lesion with and without CAD EYE were recorded simultaneously using two recorders for detection under white light imaging (WLI) and linked color imaging (LCI) and diagnosis under blue laser/light imaging (BLI). Excluding inappropriate movies, 100 lesions detected and diagnosed with CAD EYE accurately were evaluated. Movies without CAD EYE were evaluated first by three trainees and three experts. Subsequently, movies with CAD EYE were examined. The rates of accurate detection and diagnosis were evaluated for both movie sets.

Results

Among 100 lesions (mean size: 4.7±2.6 mm; 67 neoplastic/33 hyperplastic), mean accurate detection rates of movies without or with CAD EYE were 78.7%/96.7% under WLI (p<0.01) and 91.3%/97.3% under LCI (p<0.01) for trainees and 85.3%/99.0% under WLI (p<0.01) and 92.6%/99.3% under LCI (p<0.01) for experts. Mean accurate diagnosis rates of movies without or with CAD EYE for BLI were 85.3%/100% for trainees (p<0.01) and 92.3%/100% for experts (p<0.01), respectively. The significant risk factors of not-detected lesions for trainees were right-sided, hyperplastic, not-reddish, in the corner, halation, and inadequate bowel preparation.

Conclusions

Unique movie sets with and without CAD EYE could suggest it's efficacy for lesion detection/diagnosis.

Comparison of blue laser imaging and light-emitting diode-blue light imaging for the characterization of colorectal polyps using the Japan narrow-band imaging expert team classification: The LASEREO and ELUXEO COLonoscopic study

Objectives

Although the laser light is optically ideal for producing narrow-band light, it has not been used in some areas of the world. Endoscopic light sources using light-emitting diodes (LEDs) are used worldwide. The purpose of this study was to compare blue laser imaging (laser-BLI) and LED-blue light imaging (LED-BLI) for the characterization of colorectal polyps using the Japan narrow band imaging expert team (JNET) classification.

Methods

Colorectal lesions were prospectively examined using magnifying narrow-band light generated by a laser (laser-BLI) or LEDs (LED-BLI). Twelve endoscopists (six non-experts and six experts from three institutions) evaluated each still-magnified image of lesions using the JNET classification.

Results

Seven hundred and fifty-six images from 63 lesions were reviewed. The mean polyp size was 24.5 ± 13.4 mm. Histopathology included 13 serrated lesions and 50 neoplasms. The rate of agreement between laser-BLI and LED-BLI using the JNET classification was 92.5% (699/756). The weighted κ-statistic was 0.99. The percentages of "almost similar" comparing scores of surface patterns, vessel patterns, and brightness among all endoscopists were 95.4%, 95.9%, and 95.0%, respectively.

Conclusions

This multicenter study demonstrates that the rate of agreement between laser-BLI and LED-BLI using the JNET Classification is very high. The surface patterns, vessel patterns, and brightness are almost similar.

Artificial intelligence for characterization of colorectal polyps: Prospective multicenter study

Background and study aims Optical diagnosis poses challenges to implementation of "resect and discard" strategies. This study aimed to assess the feasibility and performance of a new commercially available system for colorectal polyps. Patients and methods Nine expert endoscopists in three centers performed colonoscopies using artificial intelligence-equipped colonoscopes (CAD EYE, Fujifilm). Histology and predictions were compared, with hyperplastic polyps and sessile serrated lesions grouped for analysis. Results Overall, 253 polyps in 119 patients were documented (n=152 adenomas, n=78 hyperplastic polyps, n=23 sessile serrated lesions). CAD EYE detected polyps before endoscopists in 81 of 253 cases (32%). The mean polyp size was 5.5 mm (SD 0.6 mm). Polyp morphology was Paris Ip (4 %), Is (28 %), IIa (60 %), and IIb (8 %). CAD EYE achieved a sensitivity of 80%, specificity of 83%, positive predictive value (PPV) of 96%, and negative predictive value (NPV) of 72%. Expert endoscopists had a sensitivity of 88%, specificity of 83%, PPV of 96%, and NPV of 72%. Diagnostic accuracy was similar between CAD EYE (81%) and endoscopists (86%). However, sensitivity was greater with endoscopists as compared with CAD EYE ( P <0.05). CAD EYE classified sessile serrated lesions as hyperplasia in 22 of 23 cases, and endoscopists correctly classified 16 of 23 cases. Conclusions The CAD EYE system shows promise for detecting and characterizing colorectal polyps. Larger studies are needed, however, to confirm these findings.

A novel endoscopy image fusion system: combine white light imaging and compound band imaging

PURPOSE

White light imaging (WLI) is a commonly seen examination mode in endoscopy. The particular light in compound band imaging (CBI) can highlight delicate structures, such as capillaries and tiny structures on the mucosal surface. These two modes complement each other, and doctors switch between them manually to complete the examination. This paper proposes an endoscopy image fusion system to combine WLI and CBI.

METHODS

We add a real-time rotatable color wheel in the light source device of the AQ-200 endoscopy system to achieve rapid imaging of two modes at the same position of living tissue. The two images corresponding to the pixel level can avoid registration and lay the foundation for image fusion. We propose a multi-scale image fusion framework, which involves Laplacian pyramid (LP) and convolutional sparse representation (CSR) and strengthens the details in the fusion rule.

RESULTS

Volunteer experiments and ex vivo pig stomach trials are conducted to verify the feasibility of our proposed system. We also conduct comparative experiments with other image fusion methods, evaluate the quality of the fused images, and verify the effectiveness of our fusion framework. The results show that our fused image has rich details, high color contrast, apparent structures, and clear lesion boundaries.

CONCLUSION

An endoscopy image fusion system is proposed, which does not change the doctor's operation and makes the fusion of WLI and CBI optical staining technology a reality. We change the light source device of the endoscope, propose an image fusion framework, and verify the feasibility and effectiveness of our scheme. Our method fully integrates the advantages of WLI and CBI, which can help doctors make more accurate judgments than before. The endoscopy image fusion system is of great significance for improving the detection rate of early lesions and has broad application prospects.

Comprehensive advancement in endoscopy: optical design, algorithm enhancement, and clinical validation for merged WLI and CBI imaging

As endoscopic imaging technology advances, there is a growing clinical demand for enhanced imaging capabilities. Although conventional white light imaging (WLI) endoscopy offers realistic images, it often cannot reveal detailed characteristics of the mucosa. On the other hand, optical staining endoscopy, such as Compound Band Imaging (CBI), can discern subtle structures, serving to some extent as an optical biopsy. However, its image brightness is low, and the colors can be abrupt. These two techniques, commonly used in clinical settings, have complementary advantages. Nonetheless, they require different lighting conditions, which makes it challenging to combine their imaging strengths on living tissues. In this study, we introduce a novel endoscopic imaging technique that effectively combines the advantages of both WLI and CBI. Doctors don't need to manually switch between these two observation modes, as they can obtain the image information of both modes in one image. We calibrated an appropriate proportion for simultaneous illumination with the light required for WLI and CBI. We designed a new illumination spectrum tailored for gastrointestinal examination, achieving their fusion at the optical level. Using a new algorithm that focuses on enhancing specific hemoglobin tissue features, we restored narrow-band image characteristics lost due to the introduction of white light. Our hardware and software innovations not only boost the illumination brightness of the endoscope but also ensure the narrow-band feature details of the image. To evaluate the reliability and safety of the new endoscopic system, we conducted a series of tests in line with relevant international standards and validated the design parameters. For clinical trials, we collected a total of 256 sets of images, each set comprising images of the same lesion location captured using WLI, CBI, and our proposed method. We recruited four experienced clinicians to conduct subjective evaluations of the collected images. The results affirmed the significant advantages of our method. We believe that the novel endoscopic system we introduced has vast potential for clinical application in the future.

An Analysis of Delayed Bleeding in Cases of Colorectal Endoscopic Submucosal Dissection Due to Types of Direct Oral Anticoagulants in Japan

BACKGROUND & AIMS

Reported rates of delayed bleeding (DB) after endoscopic resection using direct oral anticoagulants (DOACs) are high and heterogeneous. This large-scale multicenter study analyzed cases of DB after colorectal endoscopic submucosal dissection related to various types of DOACs in Japan (the ABCD-J study) with those associated with warfarin.

METHODS

We retrospectively reviewed 1019 lesions in patients treated with DOACs and 459 lesions in patients treated with warfarin among 34,455 endoscopic submucosal dissection cases from 47 Japanese institutions between 2012 and 2021. The DB rate (DBR) with each DOAC was compared with that with warfarin. Risk factors for DB in patients treated with DOACs or warfarin were also investigated.

RESULTS

The mean tumor sizes in the DOAC and warfarin groups were 29.6 ± 14.0 and 30.3 ± 16.4 mm, respectively. In the DOAC group, the DBR with dabigatran (18.26%) was significantly higher than that with apixaban (10.08%, P = .029), edoxaban (7.73%, P = .001), and rivaroxaban (7.21%, P < .001). Only rivaroxaban showed a significantly lower DBR than warfarin (11.76%, P = .033). In the multivariate analysis, heparin bridging therapy (odds ratio [OR], 2.18; 95% confidence interval [CI], 1.27-3.73, P = .005), rectal location (2.01, 1.28-3.16, P = .002), and procedure time ≥55 minutes (2.43, 1.49-3.95, P < .001) were significant risk factors for DB in the DOAC group. The DB risk in the DOAC group (OR, (95% CI)) was 2.13 (1.30-3.50) and 4.53 (2.52-8.15) for 1 and 2 significant risk factors, respectively.

CONCLUSIONS

Dabigatran was associated with a higher DBR than other DOACs, and only rivaroxaban was associated with a significantly lower DBR than warfarin.

Detecting colorectal lesions with image-enhanced endoscopy: an updated review from clinical trials

Colonoscopy plays an important role in reducing the incidence and mortality of colorectal cancer by detecting adenomas and other precancerous lesions. Image-enhanced endoscopy (IEE) increases lesion visibility by enhancing the microstructure, blood vessels, and mucosal surface color, resulting in the detection of colorectal lesions. In recent years, various IEE techniques have been used in clinical practice, each with its unique characteristics. Numerous studies have reported the effectiveness of IEE in the detection of colorectal lesions. IEEs can be divided into two broad categories according to the nature of the image: images constructed using narrowband wavelength light, such as narrowband imaging and blue laser imaging/blue light imaging, or color images based on white light, such as linked color imaging, texture and color enhancement imaging, and i-scan. Conversely, artificial intelligence (AI) systems, such as computer-aided diagnosis systems, have recently been developed to assist endoscopists in detecting colorectal lesions during colonoscopy. To better understand the features of each IEE, this review presents the effectiveness of each type of IEE and their combination with AI for colorectal lesion detection by referencing the latest research data.

Standard Endoscopic Mucosal Resection vs Precutting Endoscopic Mucosal Resection Using Novel Disk-Tip Snare for Colorectal Lesions

INTRODUCTION

SOUTEN (KANEKA Co., Tokyo, Japan) is a unique snare with a disk tip. We analyzed the efficacy of precutting endoscopic mucosal resection with SOUTEN (PEMR-S) for colorectal lesions.

METHODS

We retrospectively reviewed 57 lesions of 10-30 mm treated with PEMR-S at our institution from 2017 to 2022. The indications were lesions that were difficult for standard EMR due to size, morphology, and poor elevation by injection. Various therapeutic results of PEMR-S such as en bloc resection, procedure time, and perioperative hemorrhage were analyzed, and the results of 20 lesions of 20-30 mm with PEMR-S were compared to those of lesions with standard EMR (2012-2014) using propensity score matching. Additionally, the stability of the SOUTEN disk tip was analyzed in a laboratory experiment.

RESULTS

The polyp size was 16.5 ± 4.2 mm and the non-polypoid morphology rate was 80.7%. Histopathological diagnosis included 10 sessile-serrated lesions, 43 low-grade and high-grade dysplasias, and 4 T1 cancers. After matching, the en bloc resection and histopathological complete resection rates of lesions of 20-30 mm between PEMR-S and standard EMR (90.0% vs. 58.1%, p = 0.03 and 70.0% vs. 45.0%, p = 0.11). The procedure time (min) was 14.8 ± 9.7 and 9.7 ± 8.3 (p < 0.01). The en bloc resection (%) and procedure time of expert/non-expert were 89.7/85.7 (p = 0.96) and 6.1 ± 2.2/18.5 ± 7.2 (p < 0.01). The perioperative bleeding and hemostasis success rates with SOUTEN were 43.9% and 96.0%. In the experiment, the SOUTEN disk tip was fixed stably compared to other EMR snares.

CONCLUSIONS

PEMR-S achieved high en bloc resection of colorectal lesions of 20-30 mm though it leaded to long procedure time.

Colorectal Sessile Serrated Lesion Detection Using Linked Color Imaging: A Multicenter, Parallel Randomized Controlled Trial

BACKGROUND & AIMS

Linked color imaging (LCI) is a novel technology that improves the color differences between colorectal lesions and the surrounding mucosa. The present study aims to compare the detection of colorectal sessile serrated lesions (SSL) using LCI with white light imaging (WLI).

METHOD

A large-scale, multicenter, parallel prospective randomized controlled trial was conducted in 4 hospitals in China. The participants were randomly assigned to the LCI group and WLI group. The primary endpoint was the SSL detection rate (SDR).

RESULTS

A total of 884 patients were involved in the intention-to-treat analysis, with 441 patients in the LCI group and 443 patients in the WLI group. The total polyp detection rate, adenoma detection rate, and SDR were 51.8%, 35.7%, and 8.6%, respectively. The SDR was significantly higher in the LCI group than in the WLI group (11.3% vs 5.9%, P = .004). Furthermore, LCI significantly increased the number of polyps and adenomas detected per patient, when compared with WLI (P < .05). In addition, there was higher detection rate of diminutive and flat lesions in the LCI group (P < .05). Multivariate analysis revealed that LCI is an independent factor associated with SDR (hazard ratio, 1.990; 95% confidence interval, 1.203-3.293; P = .007), along with withdrawal time (hazard ratio, 1.157; 95% confidence interval, 1.060-1.263; P = .001) and operator experience (hazard ratio, 1.850; 95% confidence interval, 1.045-3.273; P = .035).

CONCLUSIONS

LCI is significantly superior to WLI for SSL detection, and may improve polyp and adenoma detection. LCI can be recommended as an appropriate method for routine inspection during colonoscopy (http://www.chictr.org.cn number, ChiCTR2000035705).

Endoscopic Diagnosis of Eosinophilic Esophagitis: Basics and Recent Advances

Eosinophilic esophagitis (EoE) is a chronic, immune-mediated inflammatory disease, characterized by esophageal dysfunction and intense eosinophil infiltration localized in the esophagus. In recent decades, EoE has become a growing concern as a major cause of dysphagia and food impaction in adolescents and adults. EoE is a clinicopathological disease for which the histological demonstration of esophageal eosinophilia is essential for diagnosis. Therefore, the recognition of the characteristic endoscopic features with subsequent biopsy are critical for early definitive diagnosis and treatment, in order to prevent complications. Accumulating reports have revealed that EoE has several non-specific characteristic endoscopic findings, such as rings, furrows, white exudates, stricture/narrowing, edema, and crepe-paper esophagus. These findings were recently unified under the EoE endoscopic reference score (EREFS), which has been widely used as an objective, standard measurement for endoscopic EoE assessment. However, the diagnostic consistency of those findings among endoscopists is still inadequate, leading to underdiagnosis or misdiagnosis. Some endoscopic findings suggestive of EoE, such as multiple polypoid lesions, caterpillar sign, ankylosaurus back sign, and tug sign/pull sign, will aid the diagnosis. In addition, image-enhanced endoscopy represented by narrow band imaging, endocytoscopy, and artificial intelligence are expected to render endoscopic diagnosis more efficient and less invasive. This review focuses on suggestions for endoscopic assessment and biopsy, including recent advances in optical technology which may improve the diagnosis of EoE.

Repeat Cold Snare Polypectomy Can Be Performed for Recurrent Benign Lesions After Cold Snare Polypectomy

BACKGROUND AND AIMS

Recurrence after cold snare polypectomy (CSP) sometimes occurs. We assessed the feasibility of repeat CSP for recurrence after CSP.

METHODS

We retrospectively reviewed recurrent lesions after CSP which were resected by repeat CSP from 2016 to 2021 in our institution and analyzed clinical outcomes of repeat CSP, comparing those of non-recurrent 454 lesions receiving standard CSP in 2016 and follow-up colonoscopy. We also analyzed the recurrent rate among cases receiving follow-up in both groups. Indication of repeat CSP was lesions diagnosed as benign tumors of ≤ 10 mm.

RESULTS

We analyzed 80 lesions receiving repeat CSP. The polyp size (mean ± standard deviation: SD) was 4.1 ± 2.3 mm (range 2-10 mm). The right-sided colon and non-polypoid morphology rates were 66.3% and 43.8%, respectively. Histopathological diagnosis was 66 adenomas, 12 sessile serrated lesions (SSLs), 1 SSL with dysplasia, and 1 high-grade dysplasia. The procedure time (min, mean ± SD) of repeat CSP was 0.9 ± 0.8. Regarding the comparison of repeat CSP/ standard CSP group, the en bloc resection and histopathological complete resection rates were 78.8%/ 98.0% (p < 0.001) and 43.8%/59.6% (p = 0.007) and the rates of perioperative hemorrhage requiring endoscopic clipping were 1.3%/ 1.0% (p = 0.646). There were no postoperative hemorrhage and perforation in both groups (p = 1.0). Among lesions receiving follow-up colonoscopy, the mean recurrence rates (number, median follow-up period: interquartile) of repeat CSP and standard CSP group were 2.0% (1/50, 12 months: 12-24) versus 0.7% (3/454, 12 months: 12-24) (p = 0.862).

CONCLUSIONS

Repeat CSP for benign recurrent lesions after CSP was safe and feasible.

Enhanced Visibility in Evaluating Gastric Cancer and Helicobacter pylori-Associated Gastritis Using Linked Color Imaging with a Light-Emitting Diode Light Source

BACKGROUND

In Japan, laser light source (Laser) endoscopy is widely available, and the characteristics of light-emitting diode light source (LED) endoscopy have not been clarified.

AIMS

We assessed the visibility of early gastric cancers (EGCs) and Helicobacter pylori (H. pylori)-associated gastritis for LED endoscopy compared with laser endoscopy using white-light imaging (WLI) and linked color imaging (LCI).

METHODS

We assessed 99 lesions between February 2019 and March 2020. The visibility was scored from four (excellent visibility) to one (poor visibility) by evaluating videos including EGCs and gastric mucosa captured using WLI and LCI with LED endoscopy (LED-WLI and LED-LCI, respectively) and laser endoscopy (Laser-WLI and Laser-LCI, respectively). The primary end point was the non-inferiority of the visibility of EGCs and H. pylori-associated gastritis between LED-/Laser-WLI and LED-/Laser-LCI.

RESULTS

The visibility scores of EGCs for LED-/Laser-WLI and LED-/Laser-LCI were 3.14/2.97 and 3.39/3.35, respectively. The visibility scores of H. pylori-associated gastritis [intestinal metaplasia (IM), diffuse redness (DR), regular arrangement of collecting venules (RAC) and map-like redness (MR)] for LED-/Laser-WLI and LED-/Laser-LCI were 3.05/2.85 and 3.60/3.50 (IM), 2.76/2.50 and 2.96/2.86 (DR), 2.69/2.44 and 2.77/2.62 (RAC) and 2.97/2.75 and 3.39/3.27 (MR). Non-inferiority was demonstrated for visualizing EGCs and H. pylori-associated gastritis.

CONCLUSIONS

LED-WLI and LED-LCI can be used to visualize EGCs and H. pylori-associated gastritis with non-inferiority to Laser-WLI and Laser-LCI. Furthermore, even with LED, LCI was more effective than WLI for evaluating EGCs and H. pylori-associated gastritis. Therefore, LED endoscopy can be used to detect EGCs and evaluate H. pylori-associated gastritis accurately.

The Efficacy of Tumor Characterization for Colorectal Lesions with Blue Light Imaging of a Compact Light-Emitting Diode Endoscopic System Compared to a Laser Endoscopic System: A Pilot Study

Background: A compact and cost-effective light source-processor combined 3-color light-emitting diode (LED) endoscopic system (ELUXEO-Lite: EP-6000, Fujifilm Co., Tokyo) with a magnified colonoscope (EC-6600ZP, Fujifilm Co.) has been released. Aims: In this study, we analyzed the efficacy of this system for colorectal tumor characterization with magnified blue light imaging (BLI-LED) and image's subjective and objective evaluations, compared to a magnified blue laser imaging (BLI-LASER) using a standard LASER endoscopic system. Methods: We retrospectively reviewed 37 lesions observed with both BLI-LED and BLI-LASER systems from 2019 using the Japanese narrow band imaging classification. Two representative magnified images, one BLI-LED and one BLI-LASER, of the same area of a lesion were evaluated for diagnostic accuracy and visualization quality by three experts and three non-experts. Their color difference values (CDVs) and brightness values (BVs) were also calculated as objective indicators. Results: Among 37 lesions, mean tumor size was 18.9 ± 13.1 mm, and 21 lesions were nonpolypoid. Histopathology revealed 14 sessile serrated lesions, 7 adenomas, 12 high-grade dysplasias and T1a cancers, and 4 T1b cancers. The diagnostic accuracy rates of BLI-LED/BLI-LASER of experts and non-experts were 90.1% and 87.4% (p = 0.52) and 89.2% and 89.2% (p = 0.99). The percentages of instances where BLI-LED images were better, the two imaging types were equivalent, or BLI-LASER images were better were 16%/83%/1% for experts and 19%/58%/23% for non-experts (p < 0.001). CDVs and BVs between BLI-LED and BLI-LASER were not significantly different (CDVs: p = 0.653, BVs: p = 0.518). Conclusions: BLI-LED using the compact system was noninferior to BLI-LASER for colorectal tumor characterization and image quality.

Comparison of the diagnostic performance of NBI, Laser-BLI and LED-BLI: a randomized controlled noninferiority trial

BACKGROUND AND AIMS

New image-enhanced endoscopy (IEE), blue Light Imaging (LED-BLI) is launched in USA and Europe, whereas Blue Laser Imaging (Laser-BLI) is available only Asian and some countries. No studies have directly compared the diagnostic accuracy of narrow band imaging (NBI), Laser-BLI and LED-BLI for colorectal tumors. The present study aimed to compare the diagnostic accuracy of the three methods for colorectal tumor using the NBI international colorectal endoscopic (NICE) classification and the Japanese NBI Expert Team (JNET) classifications.

METHODS

This was a multi-center evaluator-blinded, randomized control trial of patients who underwent endoscopic colorectal tumor resection. The patients were randomly assigned to NBI, Laser-BLI or LED-BLI. Cropped images were sent to blinded external evaluators and diagnosed according to NICE and JNET classifications. The diagnostic accuracy of each endoscopy system was compared with non-inferiority test.

RESULTS

A total of 619 colonic tumors were resected from 230 patients and evaluated by external four evaluators. The diagnostic accuracy of NBI for NICE 1, NICE 2, NICE 3 was 90.6%, 90.3% and 99.5%, respectively and for JNET 1, JNET 2A, JNET 2B and JNET 3, it was 94.6%, 72.0%, 79.2% and 99.1%, respectively. In non-inferiority test, Laser-BLI and LED-BLI revealed non-inferiority to NBI in all NICE and JNET categories (p<0.001).

CONCLUSIONS

Laser-BLI and LED-BLI had high diagnostic accuracy and non-inferiority of NBI, especially for hyperplastic polyp/sessile serrated lesion and low-grade dysplasia. This is first trial to compare the diagnostic accuracy with NBI, Laser-BLI and LED-BLI and useful to understand the position of each IEE. This trial was registered as UMIN000032107.

The usefulness of combining the pocket-creation method with a traction device using a scissor-type knife for colorectal endoscopic submucosal dissection

INTRODUCTION

Technical issues and long procedure time still remain a concern in colorectal endoscopic submucosal dissection (ESD). We examined the usefulness of combining the pocket-creation method (PCM) with a traction device (S-O clip; SO) using a scissor-type knife (Clutch Cutter 3.5 mm; CC) for decreasing ESD procedure time.

METHODS

We retrospectively analyzed 95 ESD cases of PCM + SO + CC managed from August 2017 to April 2020 and 103 cases of PCM + CC treated from July 2016 to July 2017. We compared these two groups through propensity score matching. The main outcome was the analysis of the ESD procedure times under various conditions in each group.

RESULTS

After matching, 52 cases in the PCM + SO + CC and PCM + CC groups were analyzed. The PCM + SO + CC group showed a significantly shorter ESD procedure time than the PCM + CC group (57.8 ± 31.4 vs. 81.7 ± 33.5 min, p < 0.01). Additionally, the ESD procedure time was significantly shorter in the PCM + SO + CC group than in the PCM + CC group: tumor size (tumor size < 40 mm: 45.6 ± 15.8 vs. 72.7 ± 22.9 min, p < 0.01; tumor size ≥ 40 mm: 83.1 ± 40.1 vs. 111.8 ± 45.3 min, p = 0.04), tumor location (right side: 64.7 ± 33.3 vs. 81.0 ± 29.7 min, p = 0.03; left side: 50.5 ± 28.0 vs. 82.3 ± 36.9 min, p < 0.01), tumor morphology (polypoid: 39.2 ± 18.6 vs. 74.7 ± 28.6 min, p < 0.01; nonpolypoid: 62.3 ± 32.3 vs. 84.5 ± 35.2 min, p < 0.01), endoscopist (expert: 67.3 ± 41.2 vs. 91.9 ± 40.2 min, p = 0.02; nonexpert: 50.4 ± 18.3 vs. 73.6 ± 24.9 min, p < 0.01), and fibrosis (severe fibrosis: 82.0 ± 20.5 vs. 99.8 ± 40.4 min, p = 0.169; non-severe fibrosis: 52.1 ± 23.8 vs. 75.6 ± 29.0 min, p < 0.01).

CONCLUSIONS

The combination of the PCM and SO using CC achieved a reduction in the colorectal ESD procedure time.

Comparison of blue laser imaging and narrow band imaging for the differentiation of diminutive colorectal polyps: A randomized controlled trial

BACKGROUND

To compare the diagnostic efficacy of blue laser imaging (BLI)- bright and narrow band imaging (NBI) modes of image enhanced endoscopy (IEE) in differentiating neoplastic and non-neoplastic lesions of diminutive colorectal polyps.

METHODS

We conducted a prospective randomized controlled trial from September 2015 to July 2016. The participants were randomly assigned (1:1) for colonoscopy with polyp classification under NBI or BLI-bright mode without magnification. Histopathologic diagnosis was used as the gold standard.

RESULTS

Three hundred and twenty-four diminutive polyps in 164 patients were included for analysis (BLI: 162 polyps in 73 patients, NBI: 162 polyps in 91 patients). These polyps were located at colon proximal to sigmoid (61.1 and 58.0%) and rectosigmoid colon (38.9 and 42.0%) in the BLI and NBI groups, respectively. Most polyps (71.9%) were adenomatous with one malignant polyp (0.3%). BLI achieved 86.4% accuracy, 98.3% sensitivity, 55.6% specificity, 85.2% positive predictive value (PPV), and 92.6% negative predictive value (NPV), similar to NBI which exhibited 90.1% accuracy, 99.1% sensitivity, 67.4% specificity, 88.5% PPV, and 96.9% NPV in the diagnosis of adenomatous polyps. Based on the location of the polyp, both modes of IEE provided ≥ 95% NPV for diagnosis of adenomatous polyps at the rectosigmoid colon.

CONCLUSIONS

BLI-bright and NBI modes of IEE have similar accuracy in differentiation between neoplastic and non-neoplastic lesions of diminutive polyps. Both modes provided ≥ 90% NPV which allows for the adaptation of the American Society of Gastrointestinal Endoscopy "diagnose-and-leave" recommended strategy for diminutive polyps at the rectosigmoid colon.

Electronic chromo-endoscopy: technical details and a clinical perspective

Precise endoscopic assessment is necessary to detect neoplastic changes in an early stage. Electronic or virtual chromo-endoscopy (ECE) is an alternative to conventional dye-based chromo-endoscopy which markedly improves capillary pattern and hence can detect micro-vessel morphological changes of early neoplasia to target biopsies and aid in diagnosis. The clinical significance increased after the advent of endoscopic treatment modalities like ESD/EMR which requires precise delineation of extent and depth of lesion. Most of the studies have used narrow-band imaging (NBI) (Olympus Medical Systems Tokyo, Japan), although data from i-SCAN (PENTAX Endoscopy, Tokyo, Japan) and flexible spectral imaging color enhancement (FICE) (Fujinon, Fujifilm Medical Co, Saitama, Japan) are emerging. Electronic chromo-endoscopy is convenient compared to dye-based chromo-endoscopy in the sense that it is available at the push of a button in endoscope and reduces procedure time substantially with comparable efficacy. Scope of this review is to discuss available electronic chromo-endoscopy modalities and their role in the diagnosis, surveillance, and management of early GI neoplasia.

Colorectal Cancer Surveillance in Patients with Inflammatory Bowel Diseases: Chromoendoscopy or Non-Chromoendoscopy, That Is the Question

Subjects affected by ulcerative colitis and Crohn’s disease with colonic localization have an increased risk of colorectal cancer (CRC). Surveillance colonoscopy is recommended by international guidelines as it can detect early-stage CRC. Based on previous evidence, in 2015 the Surveillance for Colorectal Endoscopic Neoplasia Detection and Management in Inflammatory Bowel Disease Patients International Consensus indicated dye chromoendoscopy (DCE) as the most effective technique for detecting dysplasia. However, advances in endoscopic technology such as high-definition colonoscopes and dye-less virtual chromoendoscopy (VCE) may change future practice. In this review, we summarize the available evidence on CRC surveillance in IBD, focusing on the emerging role of high-definition white light endoscopy (HD-WLE) and VCE over the standard DCE, and the current role of random biopsies.

Recurrence rate and lesions characteristics after cold snare polypectomy of high-grade dysplasia and T1 lesions: A multicenter analysis

BACKGROUND AND AIM

High-grade dysplasia (HGD) and T1 lesions are accidentally resected by cold snare polypectomy (CSP) and the characteristics, and follow-up of them has not been reported. In this study, we analyzed the histopathological findings and recurrence of them.

METHODS

This was a multicenter retrospective-cohort study. We collected HGD and T1 lesions of ≤ 10 mm resected by CSP among 15 520 patients receiving CSP from 2014 to 2019 at nine related institutions, and we extracted only cases receiving definite follow-up colonoscopy after CSP of HGD and T1 lesions. We analyzed these tumor's characteristics and therapeutic results such as R0 resection and local recurrence and risk factors of recurrence.

RESULTS

We collected 103 patients (0.63%) and extracted 80 lesions in 74 patients receiving follow-up colonoscopy for CSP scar. Mean age was 68.4 ± 12.0, and male rate was 68.9% (51/80). The mean tumor size (mm) was 6.6 ± 2.5, and the rate of polypoid morphology and rectum location was 77.5% and 25.0%. The rate of magnified observation was 53.8%. The rates of en bloc resection and R0 resection were 92.5% and 37.5%. The local recurrence rate was 6.3% (5/80, median follow-up period: 24.0 months). The recurrence developed within 3 months after CSP for four out of five recurrent cases. Comparing five recurrent lesions to 75 non-recurrent lesions, a positive horizontal margin was a significant risk factor (60.0% vs 10.7%, P < 0.001).

CONCLUSIONS

High-grade dysplasia and T1 resected by CSP were analyzed, and the local recurrence rate of them was substantially high.

Enhancing polyp detection: technological advances in colonoscopy imaging

The detection and removal of polyps at colonoscopy is core to the current colorectal cancer (CRC) prevention strategy. However, colonoscopy is flawed with a well described miss rate and variability in detection rates associated with incomplete protection from CRC. Consequently, there is significant interest in techniques and technologies which increase polyp detection with the aim to remedy colonoscopy's ills. Technologic advances in colonoscope imaging are numerous and include; increased definition of imaging, widening field of view, virtual technologies to supplant conventional chromocolonoscopy (CC) and now computer assisted detection. However, despite nearly two decades of technologic advances, data on gains in detection from individual technologies have been modest at best and heterogenous and conflicted as a rule. This state of detection technology science is exacerbated by use of relatively blunt metrics of improvement without consensus, the myopic search for gains over single generations of technology improvement and an unhealthy focus on adenomatous lesions. Yet there remains cause for optimism as detection gains from new technology, while small, may still improve CRC prevention. The technologies are also readily available in current generation colonoscopes and have roles beyond simply detection such as lesion characterization, further improving their worth. Coupled with the imminent expansion of computer assisted detection the detection future from colonoscope imaging advances looks bright. This review aims to cover the major imaging advances and evidence for improvement in polyp detection.

Automatic image and text-based description for colorectal polyps using BASIC classification

Colorectal polyps (CRP) are precursor lesions of colorectal cancer (CRC). Correct identification of CRPs during in-vivo colonoscopy is supported by the endoscopist's expertise and medical classification models. A recent developed classification model is the Blue light imaging Adenoma Serrated International Classification (BASIC) which describes the differences between non-neoplastic and neoplastic lesions acquired with blue light imaging (BLI). Computer-aided detection (CADe) and diagnosis (CADx) systems are efficient at visually assisting with medical decisions but fall short at translating decisions into relevant clinical information. The communication between machine and medical expert is of crucial importance to improve diagnosis of CRP during in-vivo procedures. In this work, the combination of a polyp image classification model and a language model is proposed to develop a CADx system that automatically generates text comparable to the human language employed by endoscopists. The developed system generates equivalent sentences as the human-reference and describes CRP images acquired with white light (WL), blue light imaging (BLI) and linked color imaging (LCI). An image feature encoder and a BERT module are employed to build the AI model and an external test set is used to evaluate the results and compute the linguistic metrics. The experimental results show the construction of complete sentences with an established metric scores of BLEU-1 = 0.67, ROUGE-L = 0.83 and METEOR = 0.50. The developed CADx system for automatic CRP image captioning facilitates future advances towards automatic reporting and may help reduce time-consuming histology assessment.

Clinical Applications of Linked Color Imaging and Blue Laser/Light Imaging in the Screening, Diagnosis, and Treatment of Superficial Colorectal Tumors

Considering its contribution to reducing colorectal cancer morbidity and mortality, the most important task of colonoscopy is to find all existing polyps. Moreover, the accurate detection of existing polyps determines the risk of colorectal cancer morbidity and is an important factor in deciding the appropriate surveillance program for patients. Image-enhanced endoscopy is an easy-to-use modality with improved lesion detection. Linked color imaging (LCI) and blue laser/light imaging (BLI) are useful modalities for improving colonoscopy quality. Each mode has unique optical features; therefore, their intended use differs. LCI contributes to improved polyp detection due to its brightness and high color contrast between the lesion and normal mucosa, while BLI contributes to the characterization of detected polyps by evaluating the vessel and surface patterns of detected lesions. The proper use of these observation modes allows for more efficient endoscopic diagnosis. Moreover, recent developments in artificial intelligence will soon change the clinical practice of colonoscopy and this system will provide an efficient education modality for novice endoscopists.

Blue laser-induced selective vasorelaxation by the activation of NOSs

Phototherapy has been tried for treating cardiovascular diseases. In particular, ultraviolet and blue visible lights were suggested to be useful due to their nitric oxide (NO)-production ability in the skin. However, the effects of blue light on the arterial contractility are controversial. Here, we hypothesized that appropriate protocol of blue laser can induce selective vasorelaxation by activating vasodilating signaling molecules in arteries. Using organ chamber arterial mechanics, NO assay, Matrigel assay, and microarray, we showed that a 200-Hz, 300-μs, 445-nm pulsed-laser (total energy of 600 mJ; spot size 4 mm) induced selective vasorelaxation, without vasocontraction in rat mesenteric arteries. The laser stimulation increased NO production in the cord blood-endothelial progenitor cells (CB-EPCs). Both the laser-induced vasorelaxation and NO production were inhibited by a non-selective, pan-NO synthase inhibitor, L-NG-Nitro arginine methyl ester. Microarray study in CB-EPCs suggested up-regulation of cryptochrome (CRY)2 as well as NO synthase (NOS)1 and NOSTRIN (NOS trafficking) by the laser. In conclusion, this study suggests that the 445-nm blue puled-laser can induce vasorelaxation possibly via the CRY photoreceptors and NOSs activation. The blue laser-therapy would be useful for treating systemic hypertension as well as improving local blood flow depending on the area of irradiation.

Usefulness of simultaneous type image-enhanced endoscope system in photodynamic therapy for centrally located lung cancer

BACKGROUND

Photodynamic therapy (PDT) is established as one of the standard treatment options for centrally located early lung cancer. In order to improve the effectiveness of PDT, it is very important to accurately diagnose the extent of the tumor and focus the laser irradiation accurately. With the use of the conventional video-endoscope system, which adopts the frame-sequential (RGB-based) display method, mainly used in Japan, for PDT laser irradiation, the system only recognizes the strong white light, and color information is lost. Therefore, it is difficult to irradiate the lesion while simultaneously observing the lesion. In this study, we investigated the usefulness of a new type of video-endoscope system during PDT.

METHODS

We used ELUXEO 7000® (FUJIFILM, Japan), which is a simultaneous-type video-endoscope system that has been in use at Nippon Medical School Hospital since October 2018. We analyzed the clinical usefulness of the ELUXEO® system for PDT as compared to other endoscope systems, such as EVIS LUCERA ELITE® (Olympus, Japan), an autofluorescence imaging (AFI) system.

RESULTS

After the administration of talaporfin sodium for PDT, the tumor lesion was not visualized in magenta color with AFI, yielding false-negative results. On the other hand, no false-negative results after the administration of talaporfin sodium were obtained with the use of ELUXEO®. Using the ELUXEO® system in the blue light imaging (BLI) mode, we were able to deliver a red laser light while observing the extent of the tumor. Missed laser exposure was avoided and the accuracy of PDT was improved with the use of this system.

CONCLUSIONS

ELUXEO® is useful for accurate evaluation of the extent of centrally located lung cancer and therefore, for accurate laser irradiation of the tumor lesion.

Diagnostic performance of magnifying blue laser imaging versus magnifying narrow-band imaging for identifying the depth of invasion of superficial esophageal squamous cell carcinoma

Identifying the depth of invasion (DOI) of superficial esophageal squamous cell carcinoma (SESCC) is crucial to determine the indication for endoscopic resection. This retrospective, single-center study aimed to evaluate the diagnostic efficacy of magnifying blue laser imaging (M-BLI) compared with white-light imaging (WLI) or magnifying narrow-band imaging (M-NBI) for identifying the DOI of SESCC. A total of 160 consecutive patients with SESCCs who underwent endoscopic submucosal dissection were enrolled in this study. Still images of the lesion were obtained using WLI, M-BLI and M-NBI prior to endoscopic submucosal dissection. Three endoscopists retrospectively evaluated the DOI using WLI according to non-magnifying findings and using M-BLI and M-NBI images according to the magnifying endoscopic classification of the Japan Esophageal Society. The diagnostic accuracy of each modality was compared using the chi-square test. The DOIs in 160 SESCCs evaluated pathologically were as follows: invasion to the epithelium or lamina propria mucosa in 130, invasion to the lamina muscularis mucosa or submucosa to a depth ≤ 200 μm in 18, and invasion to the submucosa to a depth > 200 μm in 12. The overall diagnostic accuracy rates of WLI, M-BLI, M-NBI, WLI with M-BLI (WLI + M-BLI), and WLI with M-NBI (WLI + M-NBI) were 86.9, 91.2, 90.6, 95.6 and 94.4%, respectively. Significant differences were found between WLI and WLI + M-BLI or WLI + M-NBI (P = 0.006 and P = 0.021, respectively). The concordance of intrapapillary capillary loops between M-BLI and M-NBI was 91.2%. The kappa coefficients for interobserver variability of the three endoscopists for M-BLI and M-NBI were 0.728/0.649/0.792 and 0.729/0.666/0.791, respectively, while those for intraobserver variability were 0.919/0.746/0.778 and 0.736/0.720/0.745, respectively. Similar to M-NBI, M-BLI was useful in predicting the DOI of SESCCs.

Cold snare polypectomy for large sessile serrated lesions is safe but follow-up is needed: a single-centre retrospective study

Background and Aim

Cold snare polypectomy (CSP) is growing in popularity due to its safety and convenience. Its indication is benign tumours such as adenoma and sessile serrated lesions (SSLs) <10 mm in size. CSP for SSLs ≥10 mm in size has not been well examined. In this study, we aimed the feasibility of this treatment regarding therapeutic results and local recurrence.

Methods

This was a single‐centre retrospective cohort study. We reviewed SSLs with or without dysplasia of 10–20 mm that were resected by CSP from 2014 to 2020. All tumours were diagnosed endoscopically as SSLs without dysplasia before CSP with the help of magnifying narrow band imaging or blue laser imaging. We analysed the lesion characteristics, en bloc resection, histopathological diagnosis, adverse events and local recurrence. We analysed risk factors for recurrence, comparing recurrent lesions to non‐recurrent lesions. We also compared risk factors for lesions 10–14 mm in size to those for lesions 15–20 mm in size.

Results

We analysed 160 lesions in 100 patients (M_age ± SD = 67.7 ± 10.1 years). The polyp size (M ± SD) was 11.8 ± 2.8 mm, and the en bloc resection rate was 60.0% (96 cases). The rates of massive perioperative haemorrhage, postoperative haemorrhage and perforation were 1.3%, 0% and 0%, respectively. Regarding histopathological diagnosis, two (1.2%) cases showed SSLs with high‐grade dysplasia. The recurrence rate in 101 lesions with a median follow‐up period of 18 months (interquartile range 12–24 months) was 5.0%. There were no significant risk factors such as tumour size, location, morphology and so on in terms of recurrence. All recurrent cases could be resected by repeat CSP. The recurrence rates of lesions 10–14 mm in size and 15–20 mm in size were 4.7% and 6.3%, respectively (p = 0.713).

Conclusion

CSP of SSLs ≥10 mm in size according to magnifying endoscopic diagnosis was safe and promising, but the rate of recurrence was slightly high, meaning that close follow‐up is required.

Diagnostic ability of Japan Narrow-Band Imaging Expert Team classification for colorectal lesions by magnifying endoscopy with blue laser imaging versus narrow-band imaging

Background and study aims  The Japan Narrow-band imaging (NBI) Expert Team (JNET) classification was proposed for evaluating colorectal lesions. However, it remains unknown whether the JNET classification can be applied to magnifying endoscopy with image-enhanced endoscopies other than NBI. This study aimed to compare the diagnostic ability of JNET classification by magnifying endoscopy with blue laser imaging (ME-BLI) and with ME-NBI. Patients and methods  We retrospectively assessed consecutive patients diagnosed per the JNET classification by ME-BLI (BLI group) or ME-NBI (NBI group) between March 2014 and June 2017. We compared the diagnostic value of JNET classification between the groups with one-to-one propensity score matching. Results  Four hundred and seventy-one propensity score-matched pairs of lesions were analyzed. In the BLI and NBI groups, the overall diagnostic accuracies were 92.1 % and 91.7 %, respectively, and those for differentiating between neoplastic and non-neoplastic polyps were 96.6 % and 96.8 %, respectively. The positive predictive value by each JNET classification in BLI vs. NBI group was 90.6 % vs. 96.2 % in Type 1, 94.3 % vs. 94.6 % in Type 2A, 57.7 % vs. 42.3 % in Type 2B, and 100 % vs. 91.7 % in Type 3. The negative predictive value was 97.0 % vs. 96.9 % in Type 1, 88.1 % vs. 82.8 % in Type 2A, 98.0 % vs. 98.2 % in Type 2B, and 98.5 % vs. 98.7 % in Type 3. No statistical difference in the diagnostic results was found between the groups. Conclusions  The diagnostic ability of the JNET classification by ME-BLI and ME-NBI was comparable, with the former also applicable for diagnosis of colorectal lesions.

A CNN CADx System for Multimodal Classification of Colorectal Polyps Combining WL, BLI, and LCI Modalities

Colorectal polyps are critical indicators of colorectal cancer (CRC). Blue Laser Imaging and Linked Color Imaging are two modalities that allow improved visualization of the colon. In conjunction with the Blue Laser Imaging (BLI) Adenoma Serrated International Classification (BASIC) classification, endoscopists are capable of distinguishing benign and pre-malignant polyps. Despite these advancements, this classification still prevails a high misclassification rate for pre-malignant colorectal polyps. This work proposes a computer aided diagnosis (CADx) system that exploits the additional information contained in two novel imaging modalities, enabling more informative decision-making during colonoscopy. We train and benchmark six commonly used CNN architectures and compare the results with 19 endoscopists that employed the standard clinical classification model (BASIC). The proposed CADx system for classifying colorectal polyps achieves an area under the curve (AUC) of 0.97. Furthermore, we incorporate visual explanatory information together with a probability score, jointly computed from White Light, Blue Laser Imaging, and Linked Color Imaging. Our CADx system for automatic polyp malignancy classification facilitates future advances towards patient safety and may reduce time-consuming and costly histology assessment.

The efficacy of tumor characterization and tumor detectability of linked color imaging and blue laser imaging with an LED endoscope compared to a LASER endoscope

OBJECTIVES

An endoscope with a light-emitting diode (LED) light source which has a 2-mm close-distance observation function without magnification, has been marketed, enabling linked color imaging (LCI) and blue laser imaging (BLI) for tumor detection and characterization. We analyzed the efficacy of a LED endoscope compared to a LASER endoscope.

METHODS

We retrospectively reviewed 272 lesions observed using the LED endoscopic system (Fujifilm Co., Tokyo, Japan) from May 2018 to September 2019. The Japanese NBI Classification was used for tumor characterization. We analyzed the diagnostic accuracy and confidence level. Sixty-one lesions observed with both the LED and magnified LASER endoscopes were also analyzed to compare the diagnostic accuracy. Regarding the tumor detectability, we calculated color difference values (CDVs) and brightness values (BVs) of white-light imaging, BLI, and LCI modes between the two endoscopes for each tumor.

RESULTS

The mean polyp size was 9.2 ± 11.3 mm. Histology showed 71 sessile serrated lesions, 193 adenoma and high-grade dysplasias, and 8 T1 cancers. The diagnostic accuracy of tumors ≥ 10 and < 10 mm was 72.0% and 92.9% (p < 0.001), respectively and the high confidence rate was 93.8%. The diagnostic accuracy of LED (77.0%) was a little higher than that of LASER without magnification (65.6%, p = 0.16) but was not inferior to that of LASER with magnification (82.0%, p = 0.50). The respective CDVs of LED and LASER endoscopes were 20.6 ± 11.2 and 21.6 ± 11.2 for LCI (p = 0.30), and the respective BVs were 210.0 ± 24.2 and 175.9 ± 21.1 (p < 0.001).

CONCLUSIONS

A LED endoscope with close-distance observation improved tumor detection and characterization due to high brightness.

Impact of new techniques on adenoma detection rate based on meta-analysis data

The high incidence of colorectal cancer and the occurrence of interval cancers after screening colonoscopy support the need to develop methods to increase adenoma detection rate (ADR). This review focuses on the importance of ADR and the impact of new techniques on ADR based on meta-analysis data. The low-cost interventions (such as water-aided colonoscopy, second observation, and dynamic position change) were effective in increasing ADR. So were enhanced imaging techniques and add-on devices. Increase with higher cost interventions such as newer scopes is uncertain. Water exchange (WE) has the highest ADR compared with water immersion, air insufflation, and carbon dioxide insufflation. Second observation with forward or retroflexed views improved the right colon ADR. Add-on devices result in only modest improvement in ADR, of particular help in low performing endoscopists. The second-generation narrow-band imaging (NBI) provided a two-fold brighter image than the previous system. The improvement in ADR with NBI required the "best" quality bowel preparation. New endoscopic techniques incur various additional costs, nil for WE, small for tip attachments but large for the newer scopes. In conclusion, one or more of the above methods to improve ADR may be applicable in Taiwan. A comparison of these approaches to determine which is the most cost-effective is warranted.

Can image-enhanced endoscopy improve the diagnosis of Kyoto classification of gastritis in the clinical setting?

Endoscopic diagnosis of Helicobacter pylori (H. pylori) infection, the most common cause of gastric cancer, is very important to clarify high-risk patients of gastric cancer for reducing morbidity and mortality of gastric cancer. Recently, the Kyoto classification of gastritis was developed based on the endoscopic characteristics of H. pylori infection-associated gastritis for clarifying H. pylori infection status and evaluating risk factors of gastric cancer. Recently, magnifying endoscopy with narrow-band imaging (NBI) has reported benefits of the accuracy and reproducibility of endoscopic diagnosis for H. pylori-related premalignant lesions. In addition to NBI, various types of image-enhanced endoscopies (IEEs) are available including autofluorescence imaging, blue laser imaging, and linked color imaging. This review focuses on understanding the clinical applications and the corresponding evidences shown to improve the diagnosis of gastritis based on Kyoto classification using currently available advanced technologies of IEEs.

Efficacy of scissor-type knives for endoscopic mucosal dissection of superficial gastrointestinal neoplasms

Endoscopic submucosal dissection (ESD) for superficial gastrointestinal neoplasms has become widespread. However, certain aspects of the procedure remain difficult to manage, such as intraoperative bleeding and perforation. There are two kinds of scissor-type knife: the Clutch Cutter (Fujifilm Co., Tokyo, Japan) and the SB knife (Sumitomo Bakelite Co., Tokyo, Japan). These knives have different features from other types of ESD knives and enable the performance of all ESD procedures, including mucosal incision, submucosal dissection, and hemostasis. The standard approach with scissor-type knives involves first grabbing the tissue and then incising or dissecting it. Theoretically, perforation as a result of unintentional movement should never happen with scissor-type knives compared to needle- or blade-type knives, which may induce perforation through unintentional movement. Moreover, the rates of severe bleeding and self-completion of ESD with scissor-type knives by non-experts were reported to be significantly better than for other knives. Thus, scissor-type knives can resolve these problems and help to further standardize ESD globally. In this review, we summarize reports on the efficacy of such scissor-type knives for ESD of gastrointestinal tumors. We also present the pocket-creation method and the application of traction devices, such as dental floss and S-O clips (Zeon Medical Co., Tokyo, Japan) for improving the performance of ESD with a Clutch Cutter.

Blue laser magnifying endoscopy in the diagnosis of chronic gastritis

The current study aimed to evaluate the clinical value of using blue laser imaging combined with magnifying endoscopy in the diagnosis of chronic gastritis (CG). The groups used were as follows: The white light group (WLI, control group), linked color imaging group (LCI, observation group 1), blue laser imaging (BLI)-bright (brt) group (BLI-brt; observation group 2), BLI + magnified imaging (ME) group (observation group 3). WLI mode initially allowed the observation of mucosal suspicious lesions on the gastric mucosa. These lesions were photographed and the mode was changed to LCI, BLI-brt and BLI + ME. Different observational patterns were compared between modes to diagnose various grades of chronic gastritis. No significant differences were observed in the baseline information of enrolled patients. The LCI mode diagnosis rate was higher for Helicobacter pylori (HP) infection than in any other mode. LCI exhibited a high diagnostic rate for HP, BLI-brt exhibited a high diagnostic rate for atrophy and BLI/BLI + ME exhibited a high diagnostic rate for intestinal metaplasia and intraepithelial neoplasia. All modes exhibited higher diagnostic rates compared with the WLI mode. The pathological HP diagnosis rate (consistency) of HP infection was the greatest in the LCI group (endoscopic findings and pathological consistency). The BLI-BRT mode exhibited the highest pathological diagnosis rate for atrophic gastritis and the BLI/BLI + ME mode exhibited the highest diagnostic rate for intestinal metaplasia and low-grade intraepithelial neoplasia.