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Comparison of different virtual chromoendoscopy classification systems for the characterization of colorectal lesions

Leonardo Zorron Cheng Tao Pu1,3, Takeshi Yamamura4, Masanao Nakamura3, Doreen S C Koay2, Amanda Ovenden2, Suzanne Edwards1, Alastair D Burt1, Yoshiki Hirooka5, Mitsuhiro Fujishiro3, Rajvinder Singh1,2

JGH Open. 2020 Jul 7;4(5):818-826. doi: 10.1002/jgh3.12382. eCollection 2020 Oct.

Background and aim: Commonly used classifications for colorectal lesions (CLs) include the Narrow Band Imaging (NBI) International Colorectal Endoscopic (NICE) and Japan NBI Expert Team (JNET) classifications. However, both lack a sessile serrated adenoma/polyp (SSA/P) category. This has been addressed by the modified Sano’s (MS) and Workgroup serrAted polypS and Polyposis (WASP) classifications. This study aims to compare the accuracy of wNICE and wJNET (WASP added to both) with the stand-alone MS classification.

Methods: Patients undergoing colonoscopy at an Australian tertiary hospital who had at least one CL detected were prospectively enrolled. In the exploratory phase, CLs were characterized in real time with NBI and magnification using all classifications. In the validation phase, CLs were assessed with both NBI and Blue Laser Imaging (BLI) by four external endoscopists in Japan. The primary outcome was the comparison of wJNET and MS. Secondary outcomes included comparisons among all classifications and the calculation of interrater reliability.

Results: A total of 483 CLs were evaluated in real time in the exploratory phase, and four sets of 30 CL images (80 on NBI and 40 on BLI) were scored in the validation phase. For high-confidence diagnoses, MS accuracy was superior to wJNET in both the exploratory (86% vs 79%, P < 0.05) and validation (85% vs 69%, P < 0.05) phases. The interrater reliability was substantial for all classifications (κ = 0.74, 0.69, and 0.63 for wNICE, wJNET, and MS, respectively).

Conclusions: MS classification achieved the highest accuracy in both the exploratory and validation phases. MS can differentiate serrated and adenomatous polyps as a stand-alone classification.

1 Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, Australia
2 Department of Gastroenterology, Lyell McEwin Hospital, Adelaide, Australia
3 Department of Gastroenterology and Hepatology, Nagoya University, Najoya, Japan
4 Department of Endoscopy, Nagoya University Hospital, Nagoya, Japan
5 Department of Gastroenterology and Gastroenterological Oncology, Fujita Health University, Toyoake, Japan

Linked color imaging improves visibility of reflux esophagitis

Tsutomu Takeda1, Daisuke Asaoka2, Daiki Abe1, Maiko Suzuki2, Yuta Nakagawa2, Hitoshi Sasaki2, Yoshihiro Inami2, Muneo Ikemura1, Hisanori Utsunomiya1, Shotaro Oki1, Nobuyuki Suzuki1, Atsushi Ikeda1, Noboru Yatagai1, Hiroyuki Komori1, Yoichi Akazawa1, Kohei Matsumoto1, Kumiko Ueda1, Hiroya Ueyama1, Yuji Shimada1, Kenshi Matsumoto1, Mariko Hojo1, Taro Osada1, Shuko Nojiri3, Akihito Nagahara1

BMC Gastroenterol. 2020 Oct 27;20(1):356. doi: 10.1186/s12876-020-01511-9.

Background: With more prevalent gastroesophageal reflux disease comes increased cases of Barrett’s esophagus and esophageal adenocarcinoma. Image-enhanced endoscopy using linked-color imaging (LCI) differentiates between mucosal colors. We compared LCI, white light imaging (WLI), and blue LASER imaging (BLI) in diagnosing reflux esophagitis (RE).

Methods: Consecutive RE patients (modified Los Angeles [LA] classification system) who underwent esophagogastroduodenoscopy using WLI, LCI, and BLI between April 2017 and March 2019 were selected retrospectively. Ten endoscopists compared WLI with LCI or BLI using 142 images from 142 patients. Visibility changes were scored by endoscopists as follows: 5, improved; 4, somewhat improved; 3, equivalent; 2, somewhat decreased; and 1, decreased. For total scores, 40 points was considered improved visibility, 21-39 points was comparable to white light, and < 20 points equaled decreased visibility. Inter- and intra-rater reliabilities (Intra-class Correlation Coefficient [ICC]) were also evaluated. Images showing color differences (ΔE) and L a* b* color values in RE and adjacent esophageal mucosae were assessed using CIELAB, a color space system.

Results: The mean age of patients was 67.1 years (range: 27-89; 63 males, 79 females). RE LA grades observed included 52 M, 52 A, 24 B, 11 C, and 3 D. Compared with WLI, all RE cases showed improved visibility: 28.2% (40/142), LA grade M: 19.2% (10/52), LA grade A: 34.6% (18/52), LA grade B: 37.5% (9/24), LA grade C: 27.3% (3/11), and LA grade D: 0% (0/3) in LCI, and for all RE cases: 0% in BLI. LCI was not associated with decreased visibility. The LCI inter-rater reliability was “moderate” for LA grade M and “substantial” for erosive RE. The LCI intra-rater reliability was “moderate-substantial” for trainees and experts. Color differences were WLI: 12.3, LCI: 22.7 in LA grade M; and WLI: 18.2, LCI: 31.9 in erosive RE (P < 0.001 for WLI vs. LCI).

Conclusion: LCI versus WLI and BLI led to improved visibility for RE after subjective and objective evaluations. Visibility and the ICC for minimal change esophagitis were lower than for erosive RE for LCI. With LCI, RE images contrasting better with the surrounding esophageal mucosa were more clearly viewed.

1 Department of Gastroenterology, Juntendo University School of Medicine,2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, Japan.
2 Department of Gastroenterology, Juntendo Tokyo Koto Geriatric Medical Center, Tokyo, Japan.
3 Department of Medical Technology Innovation Center, Juntendo University School of Medicine, Tokyo, Japan.

Detection of early stage gastric cancers in screening laser endoscopy using linked color imaging for patients with atrophic gastritis

Minoru Yamaoka1, Hiroyuki Imaeda2, Kazuya Miyaguchi1, Keigo Ashitani1, Yoshikazu Tsuzuki2, Hideki Ohgo2, Hiromitsu Soma2, Nobutaka Hirooka1, Hidetomo Nakamoto1

J Gastroenterol Hepatol. 2020 Oct 30. doi: 10.1111/jgh.15312. Online ahead of print.

Background and aims: Laser endoscopy involves blue laser imaging in bright mode (BLI-bright). Linked color imaging (LCI) is superior to white light imaging (WLI) for detecting gastric cancers. This study aimed to detect gastric cancers on screening endoscopy using not only WLI but also BLI-bright and LCI in patients with atrophic gastritis.

Patients and methods: A total of 500 patients with atrophic gastritis undergoing screening esophagogastroduodenoscopy were included. The gastric lumen was observed in the WLI mode, followed by the LCI and BLI-bright modes. When gastric neoplasms were suspected, the mode was changed to WLI, and we sprayed indigo carmine. Finally, biopsy specimens were taken for those lesions and pathological diagnosis was made. We compared the size, morphology, and color of gastric neoplasms found by the first WLI mode and those detected by only the LCI mode or BLI-bright mode.

Results: We detected 16 gastric neoplasms (3.2%), of which 13 were early gastric cancers (EGCs) and three were gastric adenomas. Ten EGCs and two gastric adenomas (75%) were detected by the first WLI mode; three EGCs and one gastric adenoma (25%) were missed by the first WLI mode and were detected by the LCI mode or BLI-bright mode. All were less than 1 cm in diameter and were reddish. Mean diameter of the lesions was significantly less for LCI-detected or BLI-bright-detected lesions than for WLI-detected lesions (7.8 vs 21.2 mm).

Conclusions: Laser endoscopy is useful for detecting EGCs by LCI for patients with atrophic gastritis.

1 Department of General Internal Medicine, Saitama Medical University, Saitama, Japan
2 Departement of Gastroenterology, Saitama Medical University, Saitama, Japan

Comparison of the diagnostic efficacy of blue laser imaging with narrow band imaging for gastric cancer and precancerous lesions: a meta-analysis

Jingyuan Zhou1, Huijie Wu1, Chenglong Fan1 , Songda Chen1 , Aiqun Liu1

Rev Esp Enferm Dig. 2020 Aug;112(8):649-658. doi: 10.17235/reed.2020.6591/2019.

Background and aims: novel endoscopic techniques including narrowband imaging (NBI) and blue laser imaging (BLI) have led to the improved detection of early stage gastric cancer and precancerous lesions. However, these techniques are not generally thought to be equivalent at present and BLI is generally considered as superior to NBI. Therefore, this comprehensive meta-analysis aimed to definitively compare the diagnostic efficacy of NBI and BLI for the diagnosis of gastric cancer and precancerous lesions.

Methods: relevant articles were identified via searches of the PubMed, Web of Science, Embase and Cochrane Library databases from their inception until October 2019. In total, 28 relevant studies were identified and incorporated into the meta-analysis. RevMan5.3 was used to assess the relative diagnostic efficacy of these two imaging modalities in these studies. The threshold was assessed using Meta-DiSc 1.4 and STATA 14.0 for bivariate regression modeling of pooled studies.

Results: the pooled sensitivity of BLI for gastric cancer was 0.89 (0.80, 0.95) and the specificity was 0.92 (0.76, 0.98). The pooled sensitivity of NBI for gastric cancer was 0.83 (0.75, 0.89) and the specificity was 0.95 (0.91, 0.97). The pooled sensitivity of BLI for precancerous lesions was 0.81 (0.71, 0.87) and the specificity was 0.90 (0.80, 0.96). The pooled sensitivity of NBI for precancerous lesions was 0.80 (0.75, 0.85) and the specificity was 0.88 (0.77, 0.94).

Conclusions: this study showed that both BLI and NBI have a very high diagnostic efficacy for the detection of gastric cancer and precancerous lesions, the sensitivity and specificity of these two approaches were similar.

1 Department of Endoscopy. Affiliated Tumor Hospital of Guangxi Medical University. Nanning, Guangxi. China

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

Tomohiro Ueda1,2, Osamu Dohi1, Yuji Naito1, Takuma Yoshida1, Yuka Azuma1, Tsugitaka Ishida1, Shinya Matsumura1, Hiroaki Kitae1, Shun Takayama1, Naoki Mizuno1, Takahiro Nakano1,3, Naoto Iwai1,4, Ryohei Hirose1, Ken Inoue1, Naohisa Yoshida1, Kazuhiro Kamada1, Kazuhiko Uchiyama1, Takeshi Ishikawa1, Tomohisa Takagi1, Hideyuki Konishi1, Ayako Nishimura5, Mitsuo Kishimoto5, Yoshito Itoh1

Dis Esophagus. 2020 Jul 21;doaa078. doi: 10.1093/dote/doaa078. Online ahead of print.

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.

1 Department of Molecular Gastroenterology and Hepatology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
2 Departement of Gastroenterology and Hepatology, Kyoto Chubu Medical Center, Nantan, Japan
3 Departement of Gastroenterology, Japanese Red Cross Society Kyoto Daiichi Hospital, Kyoto, Japan
4 Departement of Gastroenterology and Hepatology, Fukuchiyama City Hospital, Fukuchiyama, Japan
5 Department of Surgical Pathology, Kyoto Prefectural University of Medicine, Kyoto, Japan

Linked color imaging and blue light imaging for evaluating a depressed-type adenoma in the colon

Shunsuke Yamamoto1, Nima Mottacki1

Ann Gastroenterol. Jul-Aug 2020;33(4):437. doi: 10.20524/aog.2020.0466. Epub 2020 Mar 14.

A 70-year-old man with anemia attended the hospital for colonoscopy. The examination was performed using linked color imaging (LCI) and blue light imaging (BLI) with a high-definition magnifying colonoscope (EC-760ZP-VM, Fujifilm Co.). White light imaging revealed a depressed-type polyp in the ascending colon, 8 mm in size, and was assessed as 0-IIc according to the Paris classification (Fig. 1). LCI showed an enhanced image of the depressed morphology of the polyp (Fig. 1). Magnifying BLI revealed pits smaller than those seen in surrounding normal mucosa (type IIIs in Kudo classification). No signs of invasion, such as destructed pits or vessels with varied caliber, were seen (Fig. 1). Endoscopic mucosal resection was performed. The pathological diagnosis was tubular adenoma with low-grade dysplasia, as expected from the pre-treatment observation, and it was completely resected (Fig. 2).

1 Department of Internal Medicine & Clinical Nutrition, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden