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Real-time visualization of red blood cell flow inside subepithelial microvessels is performed with magnifying endoscopy. However, microvascular blood flow velocity in the colorectum has not been investigated. Here, we aimed to evaluate the blood flow velocity of microvessels of colonic polyps and to compare it with that of surrounding mucosa. We examined 50 lesions, including 30 adenomas (ADs) and 20 hyperplastic polyps (HPs). Blood flow velocities of lesions and their surrounding mucosa were evaluated using magnifying blue laser imaging (BLI) prior to endoscopic resection. Calculation of mean blood flow velocities was based on mean movement distance of one tagged red blood cell using split video images of magnifying BLI. Mean microvascular blood flow velocity was significantly lower in ADs (1.65±0.66 mm/sec; range 0.46–2.90) than in HPs (2.83±1.10 mm/sec; 1.07–4.50) or the surrounding mucosa (3.73±1.11 mm/sec; 1.80–6.20; P

Optimizing the adenoma detection rate (ADR) is a major goal in colorectal cancer (CCR) screening, as it has long been established that ADR is inversely proportional to the risk of post-colonoscopy CRC occurrence. To achieve this goal, many optimization devices have been developed, and numerous randomized controlled trials have been conducted to evaluate the benefits of these devices compared with a "standard arm," which corresponds to date to high-definition white light (HD-WLI) colonoscopy. Numerous studies have confirmed the positive impact of various optimization devices, such as caps, computer-aided detection, and contrast-enhanced technologies. Moreover, the different ways in which the devices can impact ADR make them complementary. However, despite substantial and consistent data, practices remain unchanged, and HD-WLI colonoscopy, considered the "standard," is still routinely performed without any optimization devices. The objective of this viewpoint is to understand the barriers to change and to show why standard screening colonoscopy without the use of any optimization devices should no longer be considered relevant in 2024.

Background and study aims Artificial intelligence (AI) has great potential to improve endoscopic recognition of early stage colorectal carcinoma (CRC). This scoping review aimed to summarize current evidence on this topic, provide an overview of the methodologies currently used, and guide future research. Methods A systematic search was performed following the PRISMA-Scr guideline. PubMed (including Medline), Scopus, Embase, IEEE Xplore, and ACM Digital Library were searched up to January 2024. Studies were eligible for inclusion when using AI for distinguishing CRC from colorectal polyps on endoscopic imaging, using histopathology as gold standard, reporting sensitivity, specificity, or accuracy as outcomes. Results Of 5024 screened articles, 26 were included. Computer-aided diagnosis (CADx) system classification categories ranged from two categories, such as lesions suitable or unsuitable for endoscopic resection, to five categories, such as hyperplastic polyp, sessile serrated lesion, adenoma, cancer, and other. The number of images used in testing databases varied from 69 to 84,585. Diagnostic performances were divergent, with sensitivities varying from 55.0% to 99.2%, specificities from 67.5% to 100% and accuracies from 74.4% to 94.4%. Conclusions This review highlights that using AI to improve endoscopic recognition of early stage CRC is an upcoming research field. We introduced a suggestions list of essential subjects to report in research regarding the development of endoscopy CADx systems, aiming to facilitate more complete reporting and better comparability between studies. There is a knowledge gap regarding real-time CADx system performance during multicenter external validation. Future research should focus on development of CADx systems that can differentiate CRC from premalignant lesions, while providing an indication of invasion depth., Competing Interests: Conflict of Interest Author FvdS received research support from Olympus, outside the submitted work. Author JB is a consultant for Boston Scientific. Author LM is a consultant for Boston Scientific. Author ES received research support and speakers’ fees from Fujifilm, outside the submitted work. Authors AT, RMS, ND, MS, and PdW declare no conflict of interests for this article., (The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution License, permitting unrestricted use, distribution, and reproduction so long as the original work is properly cited. (https://creativecommons.org/licenses/by/4.0/).)

Background and study aims We previously demonstrated the efficacy of an additional-30-seconds (Add-30s) observation with linked color imaging (LCI) or narrow band imaging (NBI) of the cecum and ascending colon (right-sided colon) after white light imaging (WLI) observation for improving adenoma detection rate (ADR) by 3% to 10%. We herein compared Add-30s LCI with Add-30s NBI in a large number of cases. Patients and methods We retrospectively collected 1023 and 1011 cases with Add-30s LCI and NBI observation for right-sided colon in 11 affiliated institutions from 2018 to 2022 and propensity score matching was performed. Add-30s observation was as follows. First observation: WLI observation of the right-sided colon as first observation. Second observation: Reobservation of right-sided colon by Add-30s LCI or NBI. The comparison of the mean numbers of adenoma+sessile serrated lesions (SSLs) and adenomas per patient (MASP and MUTYH-associated polyposis) were analyzed in the Add-30s LCI/NBI groups. The increase in right-sided ADR was also analyzed in the groups. Results Among 748 matched cases in the Add-30s LCI/NBI groups, the MASP and MAP were 0.18/0.19 ( P = 0.54) and 0.14/0.15 ( P = 0.70). Among experts, they were 0.17/0.22 ( P = 0.16) and 0.15/0.21 ( P = 0.08). Among non-experts, they were 0.13/0.12 ( P = 0.71) and 0.12/0.07 ( P = 0.04). The right-sided ADRs of the first+second observations in the LCI and NBI groups were 32.2% and 28.9% ( P = 0.16) and the increase of ADRs were 7.5% and 7.2% ( P = 0.84). Conclusions In right-sided colon, the detection of adenoma/SSL did not differ between Add-30s LCI and NBI. Both of them significantly increased ADR., Competing Interests: Conflict of Interest Yoshida N and Dohi O have received a research grant from Fujifilm. Yoshida N have received payment for lectures from Fujifilm. The other author declares no conflict of interest for this article., (The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial-License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/).)

Background and study aims The safety of endoscopic submucosal dissection (ESD) has been reported, and the risk of lymph node metastasis is low for colorectal cancer if depth of invasion is the only non-curative factor on histological evaluation. ESD is increasingly performed even if submucosal (SM) invasion is suspected. However, reports about endoscopic findings for the criteria to predict ESD resectability remain limited. Endoscopic ultrasound (EUS) can directly visualize the tomographic image of the gastrointestinal wall and may help predict ESD resectability. Therefore, we investigated the possibility of predicting ESD resectability using EUS. Patients and methods We compared the association between EUS findings and pathological results for gastric or colorectal lesions with suspected SM invasion using white light endoscopy between June 2020 and January 2023. EUS findings were grouped based on the status of the underlying the tumor, as follows: Type I, submucosal layer was observed with reproducibility; Type II, submucosal layer not fully visible; and Type III, submucosal layer disrupted and muscularis propria (MP) layer thickened. Results Forty-one gastric cancer and 22 colorectal cancer cases were analyzed. The proportions of pathological VM0 (no tumor exposed on any vertical margin) for ESD-resected specimens were 89% and 33% for Type I and II, respectively, ( P ≤ 0.01). The proportions of cancer involving MP or deeper were significantly higher for Type II/III than for Type I (41% vs 0%, P ≤ 0.01). Conclusions EUS may have an important role in predicting ESD resectability of gastric and colorectal cancers suspected of having SM invasion., Competing Interests: Conflict of Interest The authors declare that they have no conflict of interest., (The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial-License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/).)

Background and study aims Accurate endoscopic characterization of colorectal lesions is essential for predicting histology but is difficult even for experts. Simple criteria could help endoscopists to detect and predict malignancy. The aim of this study was to evaluate the value of the green sign and chicken skin aspects in detection of malignant colorectal neoplasia. Patients and methods We prospectively characterized and evaluated the histology of all consecutive colorectal lesions detected during screening or referred for endoscopic resection (Pro-CONECCT study). We evaluated the diagnostic accuracy of the green sign and chicken skin aspects for detection of superficial and deep invasive lesions. Results 461 patients with 803 colorectal lesions were included. The green sign had a negative predictive value of 89.6% (95% confidence interval [CI] 87.1%-91.8%) and 98.1% (95% CI 96.7%-99.0%) for superficial and deep invasive lesions, respectively. In contrast to chicken skin, the green sign showed additional value for detection of both lesion types compared with the CONECCT classification and chicken skin (adjusted odds ratio [OR] for superficial lesions 5.9; 95% CI 3.4-10.2; P <0.001), adjusted OR for deep lesions 9.0; 95% CI 3.9-21.1; P <0.001). Conclusions The green sign may be associated with malignant colorectal neoplasia. Targeting these areas before precise analysis of the lesion could be a way of improving detection of focal malignancies and prediction of the most severe histology., Competing Interests: Conflict of Interest The authors declare that they have no conflict of interest., (The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial-License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/).)

Background and study aims Sessile serrated lesions (SSLs) are precursor lesions in the serrated neoplasia pathway that lead to invasive carcinoma from dysplasia arising from SSLs. This study aimed to elucidate the clinicopathological and endoscopic features of SSLs with and without dysplasia or carcinoma. Patients and methods We reviewed the clinicopathological and endoscopic data from all colorectal lesions pathologically diagnosed as SSLs at Juntendo University Hospital, Tokyo, Japan, between 2011 and 2022. In addition to conventional endoscopic findings, we retrospectively evaluated magnifying endoscopic findings with narrow-band imaging (NBI) or blue laser imaging (BLI) using the Japan NBI Expert Team system and analyzed pit patterns using magnified chromoendoscopic images. Results Of the 2,132 SSLs, 92.5%, 4.7%, 1.8%, and 0.9% had no dysplasia, low-grade dysplasia, high-grade dysplasia, and submucosal invasive carcinoma, respectively. Older age, the proximal colon, and larger lesions were more frequently associated with SSLs with dysplasia or carcinoma. However, 41.3% of the SSLs with dysplasia or carcinoma were ≤ 10 mm in size. Endoscopic findings, such as (semi)pedunculated morphology, double elevation, central depression, and reddishness, were frequently found in SSLs with dysplasia or carcinoma. Furthermore, magnifying endoscopy using NBI or BLI and magnifying chromoendoscopy showed high sensitivity, specificity, and accuracy for diagnosing dysplasia or carcinoma within SSLs. Conclusions SSLs with and without dysplasia or carcinoma exhibit distinct clinicopathological and endoscopic features. In an SSL series, conventional endoscopic characteristics in addition to use of magnifying endoscopy may be useful for accurately diagnosing advanced histology within an SSL., Competing Interests: Conflict of Interest The authors declare that they have no conflict of interest., (The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial-License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/).)

Real-time visualization of red blood cell flow inside subepithelial microvessels is performed with magnifying endoscopy. However, microvascular blood flow velocity in the colorectum has not been investigated. Here, we aimed to evaluate the blood flow velocity of microvessels of colonic polyps and to compare it with that of surrounding mucosa. We examined 50 lesions, including 30 adenomas (ADs) and 20 hyperplastic polyps (HPs). Blood flow velocities of lesions and their surrounding mucosa were evaluated using magnifying blue laser imaging (BLI) prior to endoscopic resection. Calculation of mean blood flow velocities was based on mean movement distance of one tagged red blood cell using split video images of magnifying BLI. Mean microvascular blood flow velocity was significantly lower in ADs (1.65±0.66 mm/sec; range 0.46-2.90) than in HPs (2.83±1.10 mm/sec; 1.07-4.50) or the surrounding mucosa (3.73±1.11 mm/sec; 1.80-6.20; P <0.001). The blood flow velocity rate compared with the surrounding mucosa was significantly lower in ADs (0.41±0.16; 0.10-0.82) than in HPs (0.89±0.25; 0.46-1.51; P <0.001). We found that mean microvascular blood flow velocity was significantly lower in ADs than in HPs and the surrounding non-neoplastic mucosa. These findings indicate that a novel dynamic approach with microvascular blood flow velocity using magnifying endoscopy may be useful in assessing physiological differences between ADs and HPs., Competing Interests: Conflict of Interest The authors declare that they have no conflict of interest., (The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial-License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/).)

Background and study aims Colorectal endoscopic submucosal dissection (ESD) is increasingly used for treating early-stage colorectal cancer, including large, protruded lesions (LPL). However, the challenges posed by LPLs, especially those accompanied by severe fibrosis or muscle-retracting sign (MRS), remain unclear. This study aims to investigate ESD outcomes for LPL, focusing on factors such as tumor size and, submucosal fibrosis. Patients and methods In a multicenter retrospective study (June 2012 to May 2023), data from 526 patients with 542 LPL lesions (≥ 2 cm) were analyzed. Parameters included lesion size, procedure time, dissection speed, physician experience, submucosal fibrosis, and adverse events. The tunnel method, including the double tunnel method, was used for cases with severe fibrosis or MRS. Multivariate analysis assessed factors affecting procedure difficulty, particularly LPLs ≥ 4 cm. Results The study revealed an impressive en bloc resection rate of 97.8% and a curative resection rate of 78.6% for LPLs. Notably, fibrosis and MRS were present in 25% and 18% of 4-cm LPLs, respectively, and their frequency tended to increase as the tumor diameter increased. One treatment strategy for LPLs was the tunneling method, which was used most frequently (41 cases, 7.6%). Factors affecting dissection speed included larger tumor size, submucosal fibrosis, MRS, and physician experience. Conclusions Treating LPLs through colorectal ESD presents significant challenges, especially in patients with fibrosis and MRS. This study highlights the importance of recognizing these complexities, and that more reliable resection strategy must be established for accurate pathological evaluation., Competing Interests: Conflict of Interest The authors declare that they have no conflict of interest., (The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial-License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/).)

Background and study aims Artificial Intelligence (AI) systems could make the optical diagnosis (OD) of diminutive colorectal polyps (DCPs) more reliable and objective. This study was aimed at prospectively evaluating feasibility and diagnostic performance of AI-standalone and AI-assisted OD of DCPs in a real-life setting by using a white light-based system (GI Genius, Medtronic Co, Minneapolis, Minnesota, United States). Patients and methods Consecutive colonoscopy outpatients with at least one DCP were evaluated by 11 endoscopists (5 experts and 6 non-experts in OD). DCPs were classified in real time by AI (AI-standalone OD) and by the endoscopist with the assistance of AI (AI-assisted OD), with histopathology as the reference standard. Results Of the 480 DCPs, AI provided the outcome "adenoma" or "non-adenoma" in 81.4% (95% confidence interval [CI]: 77.5-84.6). Sensitivity, specificity, positive and negative predictive value, and accuracy of AI-standalone OD were 97.0% (95% CI 94.0-98.6), 38.1% (95% CI 28.9-48.1), 80.1% (95% CI 75.2-84.2), 83.3% (95% CI 69.2-92.0), and 80.5% (95% CI 68.7-82.8%), respectively. Compared with AI-standalone, the specificity of AI-assisted OD was significantly higher (58.9%, 95% CI 49.7-67.5) and a trend toward an increase was observed for other diagnostic performance measures. Overall accuracy and negative predictive value of AI-assisted OD for experts and non-experts were 85.8% (95% CI 80.0-90.4) vs. 80.1% (95% CI 73.6-85.6) and 89.1% (95% CI 75.6-95.9) vs. 80.0% (95% CI 63.9-90.4), respectively. Conclusions Standalone AI is able to provide an OD of adenoma/non-adenoma in more than 80% of DCPs, with a high sensitivity but low specificity. The human-machine interaction improved diagnostic performance, especially when experts were involved., Competing Interests: Conflict of Interest Paggi S and Amato A: speaker honoraria from Fujifilm Co. Rondonotti E: speaker honoraria from Fujifilm Co., Medtronic Co. consultancy. Radaelli F: Speaker honoraria from Fujifilm Co; research grant from Fujifilm Co; endoscopy equipment loan from Medtronic Co. Hassan C: Medtronic Co, Fujifilm Co and Odin Co. consultancy. All the other authors declare no conflict of interest., (The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial-License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/).)

Background and study aims Chronically inflamed colonic mucosa is primed to develop dysplasia identified at surveillance colonoscopy by targeted or random biopsies. We aimed to explore the effect of mucosal inflammation on detection of visible and "invisible" dysplasia and the concordance between the degree of endoscopic and histologic inflammation. Patients and methods This was a 6-year cross-sectional analysis of endoscopic and histologic data from IBD. A multinomial model was created to estimate the odds for a specific lesion type as well as the odds of random dysplasia relative to the degree of inflammation. Kappa statistics were used to measure concordance between endoscopic and histologic inflammation. Results A total of 3437 IBD surveillance colonoscopies between 2016-2021 were reviewed with 970 procedures from 721 patients containing 1603 visible lesions. Kappa agreement between histologic and endoscopic degree of inflammation was low at 0.4. There was a positive association between increased endoscopic inflammation and presence of tubulovillous adenomas (TVAs) (odds ratio [OR] 2.18; 95% confidence interval [CI] 1.03-4.62; P =0.04). Among cases with visible lesions, the yield of concomitant random dysplasia was 2.7% and 1.9% for random indefinite dysplasia. The odds of random dysplasia significantly increased as the degree of endoscopic and histologic inflammation increased (OR 2.18, 95%CI 1.46-3.26; P <0.001 and OR 2.75; 95%CI 1.65-4.57, P <0.001, respectively. The odds of indefinite random dysplasia also significantly increased as endoscopic and histologic inflammation increased (OR 2.90; 95%CI 1.85, 4.55, P <0.001 and OR 1.98; 95%CI 1.08, 3.62, P <0.035, respectively. Conclusions Endoscopic and histologic inflammation are associated with higher odds of finding TVAs and random low-grade, high-grade, and indefinite dysplasia. Concordance between histologic and endoscopic inflammation severity is low., Competing Interests: Conflict of Interest Nayantara Coelho-Prabhu: research funding from Cook Endoscopy, Fujifilm, Alexion Pharma. The remaining authors have no conflict of interest to declare., (The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial-License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/).)