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Detection of colorectal neoplasms using linked color imaging: A prospective, randomized, tandem colonoscopy trial

Issei Hasegawa1, Takeshi Yamamura1, Hiroto Suzuki1, Keiko Maeda2, Tsunaki Sawada2, Yasuyuki Mizutani1, Eri Ishikawa1, Takuya Ishikawa1, Naomi Kakushima 1, Kazuhiro Furukawa1, Eizaburo Ohno1, Hiroki Kawashima2, Masanao Nakamura1, Mitsuhiro Fujishiro1

Clin Gastroenterol Hepatol. 2021 Apr 8;S1542-3565(21)00392-X. doi: 10.1016/j.cgh.2021.04.004. Online ahead of print.

Background and aims: A higher adenoma detection rate (ADR) has been shown to be related to a lower incidence and mortality of colorectal cancer. We analyzed the efficacy of linked color imaging (LCI) by assessing the detection, miss, and visibility of various featured adenomas as compared with white light imaging (WLI).

Methods: This was a prospective, randomized, tandem trial. The participants were randomly assigned to two groups: first observation by LCI, then second observation by WLI (LCI group); or both observations by WLI (WLI group). Suspected neoplastic lesions were resected after magnifying image-enhanced endoscopy. The primary outcome was to compare the ADR during the first observation. Secondary outcomes included evaluation of adenoma miss rate (AMR) and visibility score.

Results: Seven-hundred eighty patients were randomized, 700 of whom were included in the final analysis. The ADR was 69.6% and 63.2% in the LCI and WLI groups, respectively, with no significant difference. However, LCI improved the average ADR in low-detectors compared to high-detectors (76.0% vs 55.1%; P < 0.001). Total AMR was 20.6% in the LCI group, which was significantly lower than that in the WLI group (31.1%) (P < 0.001). AMR in the LCI group was significantly lower, especially for diminutive adenomas (23.4% vs 35.1%; P < 0.001) and non-polypoid lesions (25.6% vs 37.9%; P < 0.001) compared to the WLI group.

Conclusion: Although both methods provided a similar ADR, LCI had a lower AMR than WLI. LCI could benefit endoscopists with lower ADR, an observation that warrants additional study.

1 Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya, Japan
2 Department of Endoscopy, Nagoya University Hospital, Nagoya, Japan

Evaluation of Minimal Change Lesions Using Linked Color Imaging in Patients With Nonerosive Reflux Esophagitis

Ni-Na Zhang 1, Yi-Min Ma2, Qi Sun1, Liang-Liang Shi1, Yin Xie1, Xiao-Ping Zou1

J Clin Gastroenterol. 2021 Apr 13. doi: 10.1097/MCG.0000000000001538. Online ahead of print.

Background and aims: High prevalence of minimal change lesion (MCL) in nonerosive reflux esophagitis (NERD) patients is commonly recognized by many endoscopists. However, it is difficult to detect MCL with conventional white-light imaging (WLI) endoscopy. Linked color imaging (LCI), a novel image-enhanced endoscopy technology with strong, unique color enhancement, is used for easy recognition of early gastric cancer and detection of Helicobacter pylori infection. The aim of the study was to compare the efficacy of LCI and WLI endoscopy in evaluating MCL in patients with NER.

Materials and methods: Forty-one patients with NERD and 38 subjects with nongastroesophageal reflux disease (non-GERD) were recruited in this study between August 2017 and July 2018. During upper gastrointestinal endoscopy, the distal 5 cm of the esophageal mucosal morphology at the squamocolumnar junction was visualized using WLI followed by LCI. MCL was defined as areas of erythema, blurring of the Z-line, friability, decreased vascularity, white turbid discoloration, and edema or accentuation of the mucosal folds. Three experienced endoscopists evaluated the color patterns for MCL on WLI images and on WLI combined with LCI images in both groups. A biopsy was taken 2 cm above the esophagogastric junction. Histologic slides were scored by a pathologist in a blinded manner.

Results: The proportion of MCL was higher in the patients with NERD (70.7%, 29/41) than in patients with non-GERD (39.5%, 15/38) using WLI combined with LCI. In 12 patients with NERD, both WLI and LCI showed normal mucosa. The MCL detection rate was significantly higher when using WLI combined with LCI than when using WLI (70.7% vs. 51.2%, P=0.039) in patients with NERD. The histopathologic score of MCL (+) was significantly higher than that of MCL (-) patients in both the NERD group (4.59±0.32 vs. 2.36±0.34, P<0.01) and the non-GERD group (3.47±0.50 vs. 2.00±0.28, P<0.01). The intraobserver reproducibility levels and interobserver agreement were better with LCI than with WLI alone.

Conclusions: Frequency of MCL was higher in patients with NERD than in those with non-GERD. MCL can be identified by using WLI combined with LCI in patients with NERD. By enhancing endoscopic images, LCI is more sensitive in detecting MCL compared with WLI.

1 Department of Gastroenterology, The Affiliated Drum Tower Hospital of Nanjing University Medical School
2 Nanjing Drum Tower Hospital. Clinical College of Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu Province, People’s Republic of China.

Diagnostic value of linked color imaging based on endoscopy for gastric intestinal metaplasia: a systematic review and meta-analysis

Xiaochuang Shu1,2,3, Guozhi Wu1,2,3, Yanjun Zhang4, Yuping Wang2,3, Ya Zheng2,3, Qinghong Guo2,3, Rui Ji2,3, Yongning Zhou2,3

Ann Transl Med. 2021 Mar;9(6):506. doi: 10.21037/atm-21-1051.

Background: The diagnostic value of linked color imaging based on endoscopy for gastric intestinal metaplasia has shown variable results. Therefore, this meta-analysis sought to systematically evaluate the value of linked color imaging (LCI) based on the blue laser endoscopy system for the diagnosis of gastric intestinal metaplasia (GIM).

Methods: Literature searches were conducted of electronic databases including PubMed, Embase, the Cochrane Library, and Web of Science to screen diagnostic tests of LCI. The random-effects model was adopted to calculate the diagnostic efficacy of LCI for GIM. Meta-DiSc 1.40 software was applied for the calculation of sensitivity, specificity, and likelihood ratios; symmetric receiver operator characteristic (SROC) curves were drawn, and the areas under the SROC curves (AUCs) were computed. Quality of the included studies was chosen to assess using the quality assessment of diagnostic accuracy studies-2 (QUADAS-2) tool.

Results: Six original studies involving 700 participants were included in the meta-analysis. The pooled sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio of LCI for diagnosing GIM were 0.87 (0.83-0.91), 0.86 (0.82-0.89), 5.72 (3.63-8.99), and 0.17 (0.08-0.36), respectively. SROC curve analysis showed that the AUC value was 0.9283.

Discussion: Our study shows that LCI can be used for the accurate diagnosis of GIM. Considering weaknesses of available studies in terms of design, further studies with rigorous design are in need for further validating the findings of this meta-analysis.

1 The First Clinical Medical College of Lanzhou University, Lanzhou, China
2 Department of Gastroenterology, The First Hospital of Lanzhou University, Lanzhou, China
3 Key Laboratory for Gastrointestinal Diseases of Gansu Province, Lanzhou University, Lanzhou, China
4 General Internal Medicine Department of Donggang Branch, The First Hospital of Lanzhou University, Lanzhou, China

External validation of blue light imaging (BLI) criteria for the optical characterization of colorectal polyps by endoscopy experts

Madhav Desai1,2, Kevin Kennedy3 Hiroyuki Aihara4, Jacques Van Dam5, Seth Gross 6, Gregory Haber6, Heiko Pohl7, Douglas Rex8, John Saltzman4, Amrita Sethi9, Irving Waxman10, Kenneth Wang11, Michael Wallace12, Alessandro Repici 13, Prateek Sharma1,2

J Gastroenterol Hepatol. 2021 Apr 30. doi: 10.1111/jgh.15529. Online ahead of print.

Background and aim: Recently, the BLI Adenoma Serrated International Classification (BASIC) system was developed by European experts to differentiate colorectal polyps. Our aim was to validate the BASIC classification system among the US-based endoscopy experts.

Methods: Participants utilized a web-based interactive learning system where the group was asked to characterize polyps using the BASIC criteria: polyp surface (presence of mucus, regular/irregular and [pseudo]depressed), pit appearance (featureless, round/non-round with/without dark spots; homogeneous/heterogeneous distribution with/without focal loss), and vessels (present/absent, lacy, peri-cryptal, irregular). The final testing consisted of reviewing BLI images/videos to determine whether the criteria accurately predicted the histology results. Confidence in adenoma identification (rated “1” to “5”) and agreement in polyp (adenoma vs non-adenoma) identification and characterization per BASIC criteria were derived. Strength of interobserver agreement with kappa (k) value was reported for adenoma identification.

Results: Ten endoscopy experts from the United States identified conventional adenoma (vs non-adenoma) with 94.4% accuracy, 95.0% sensitivity, 93.8% specificity, 93.8% positive predictive value, and 94.9% negative predictive value using BASIC criteria. Overall strength of interobserver agreement was high: kappa 0.89 (0.82-0.96). Agreement for the individual criteria was as follows: surface mucus (93.8%), regularity (65.6%), type of pit (40.6%), pit visibility (66.9%), pit distribution (57%), vessel visibility (73%), and being lacy (46%) and peri-cryptal (61%). The confidence in diagnosis was rated at high ≥4 in 67% of the cases.

Conclusions: A group of US-based endoscopy experts hsave validated a simple and easily reproducible BLI classification system to characterize colorectal polyps with >90% accuracy and a high level of interobserver agreement.

1 Department of Gastroenterology, Kansas City VA Medical Center
2 Division of Gastroenterology, Hepatology and Motility, University of Kansas School of Medicine
3 Department of Biostatistics, St. Luke’s Hospital, Kansas City, Missouri
4 Division of Gastroenterology, Hepatology and Endoscopy, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts
5 Division of Gastroenterology, Hepatology and Nutrition, Keck School of Medicine University of Southern California, Los Angeles, California
6 Division of Gastroenterology and Hepatology, Department of Medicine, NYU Langone Medical Center
7 Division of Digestive and Liver Diseases, Columbia University Medical Center, New York, New York
8 Section of Gastroenterology and Hepatology, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire
9 Department of Gastroenterology and Hepatology, Indiana University School of Medicine, Indianapolis, Indiana
10 Gastroenterology, Hepatology and Nutrition, University of Chicago Medicine, Chicago, Illinois
11 Department of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota
12 Department of Gastroenterology and Hepatology, Mayo Clinic, Jacksonville, Florida, USA
13 Digestive Endoscopy Unit, Division of Gastroenterology, Humanitas Clinical and Research Center, Milan, Italy

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

Renma Ito1, Hiroaki Ikematsu1, Tatsuro Murano1, Kensuke Shinmura1, Motohiro Kojima2, Kana Kumahara1, Yasuaki Furue1, Hironori Sunakawa1, Tatsunori Minamide 1, Daiki Sato1, Yoichi Yamamoto1, Kenji Takashima1, Yusuke Yoda1, Keisuke Hori 1, Tomonori Yano1

Endosc Int Open. 2021 Feb;9(2):E271-E277. doi: 10.1055/a-1324-3083. Epub 2021 Feb 3.

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.

1 Department of Gastroenterology and Endoscopy
2 Division of Pathology, National Cancer Center Hospital East

Dynamic diagnosis of early gastric cancer with microvascular blood flow rate using magnifying endoscopy (with video): A pilot study

Hiroya Ueyama1, Noboru Yatagai1, Atsushi Ikeda1, Yoichi Akazawa1, Hiroyuki Komori1, Tsutomu Takeda1, Kohei Matsumoto1, Kumiko Ueda1, Kenshi Matsumoto1, Daisuke Asaoka1, Mariko Hojo1, Takashi Yao2, Akihito Nagahara1

J Gastroenterol Hepatol. 2021 Feb 3. doi: 10.1111/jgh.15425. Online ahead of print.

Background and aim: Magnifying endoscopy (ME) diagnostic algorithm for early gastric cancer (EGC) relies on qualitative features such as microvascular (MV) architecture and microsurface structure; however, it is a “static” diagnostic algorithm that uses still images. ME can visualize red blood cell flow within subepithelial microvessels in real time. Here, we evaluated the utility of using the MV blood flow rate in combination with ME for the diagnosis of EGC as a retrospective study.

Methods: Patients with differentiated-type EGC (n = 10) or patchy redness (n = 10) underwent ME with blue laser imaging. The mean MV blood flow rates of EGC, patchy redness, and background mucosa were calculated by the mean movement distance of one tagging red blood cell using split images of ME with blue laser imaging videos. We compared the mean MV blood flow rate between EGC, patchy redness, and background mucosa and also calculated the MV blood flow imaging ratio (inside lesion/background mucosa) between EGC and patchy redness.

Results: Mean MV blood flow rate was significantly lower in EGC (1481 μm/s; range 1057-1762) than in patchy redness (3859 μm/s; 2435-5899) or background mucosa (4140.6 μm/s; 2820-6247) (P < 0.01). The MV blood flow imaging ratio was significantly lower in EGC (0.39; 0.27-0.62) than in patchy redness (0.90; 0.78-1.1) (P < 0.01).

Conclusions: Dynamic diagnosis with MV blood flow rate using ME may be useful for the differential diagnosis of EGC and patchy redness. Endoscopic assessment of dynamic processes within the gastric mucosa may facilitate the diagnosis of EGC.

1 Department of Gastroenterology, Juntendo University School of Medicine
2 Department of Human Pathology, Juntendo University Graduate School of Medicine, Tokyo, Japan