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Publications on Blue Laser / BLI

Linked Color Imaging and the Kyoto Classification of Gastritis: Evaluation of Visibility and Inter-Rater Reliability.

Takeda T1, Asaoka D1, Nojiri S4, Nishiyama M1, Ikeda A1, Yatagai N1, Ishizuka K1, Hiromoto T1, Okubo S1, Suzuki M1, Nakajima A1, Nakatsu Y2, Komori H1, Akazawa Y1, Nakagawa Y1, Izumi K1, Matsumoto K1, Ueyama H1, Sasaki H1, Shimada Y3, Matsumoto K1, Osada T2, Hojo M1, Kato M5, Nagahara A1

Digestion. 2019 Jul 12:1-10. doi: 10.1159/000501534. [Epub ahead of print]

Background & aims: To compare white light imaging (WLI) with linked color imaging (LCI) and blue LASER imaging (BLI) in endoscopic findings of Helicobacter pylori presently infected, previously infected, and uninfected gastric mucosae for visibility and inter-rater reliability.

Methods: WLI, LCI and BLI bright mode (BLI-bright) were used to obtain 1,092 endoscopic images from 261 patients according to the Kyoto Classification of Gastritis. Images were evaluated retrospectively by 10 experts and 10 trainee endoscopists and included diffuse redness, spotty redness, map-like redness, patchy redness, red streaks, intestinal metaplasia, and an atrophic border (52 cases for each finding, respectively). Physicians assessed visibility as follows: 5 (improved), 4 (somewhat improved), 3 (equivalent), 2 (somewhat decreased), and 1 (decreased). Visibility was assessed from totaled scores. The inter-rater reliability (intraclass correlation coefficient) was also evaluated.

Results: Compared with WLI, all endoscopists reported improved visibility with LCI: 55.8% for diffuse redness; LCI: 38.5% for spotty redness; LCI: 57.7% for map-like redness; LCI: 40.4% for patchy redness; LCI: 53.8% for red streaks; LCI: 42.3% and BLI-bright: 80.8% for intestinal metaplasia; LCI: 46.2% for an atrophic border. For all endoscopists, the inter-rater reliabilities of LCI compared to WLI were 0.73-0.87.

Conclusion: The visibility of each endoscopic finding was improved by LCI while that of intestinal metaplasia was improved by BLI-bright.

1 Department of Gastroenterology, Juntendo University School of Medicine, Tokyo, Japan
2 Department of Gastroenterology, Juntendo University Urayasu Hospital, Chiba, Japan
3 Department of Gastroenterology, Juntendo Sizuoka Hospital, Shizuoka, Japan
4 Department of Medical Technology Innovation Center Juntendo University School of Medicine, Tokyo, Japan
5 Department of Gastroenterology, National Hospital Organization Hakodate National Hospital, Hakodate, Japan

Impact of linked-color imaging on colorectal adenoma detection.

Dos Santos CEO1, Malaman D1, Pereira-Lima JC2, de Quadros Onófrio F2, Ribas Filho JM3.

Gastrointest Endosc. 2019 Jul 11. pii: S0016-5107(19)32052-8. doi: 10.1016/j.gie.2019.06.045. [Epub ahead of print]

Background and aims: Linked-color imaging (LCI) is a new technology that emphasizes changes in mucosal color by providing clearer and brighter images, thus allowing red and white areas to be more clearly visualized. We investigated whether LCI increases the detection of colorectal adenomas when compared with white-light imaging (WLI) and blue-laser imaging (BLI)-bright.

Methods: Consecutive patients undergoing colonoscopy were randomized (1:1:1) into examination by WLI, BLI-bright, or LCI during withdrawal of the colonoscope. The adenoma detection rate (ADR), mean number of adenomas per patient, and withdrawal time were evaluated. The lesions were evaluated according to size, morphology, location, and histology.

Results: A total of 379 patients were randomized, and 412 adenomas were detected. ADR was 43.2%, 54.0%, and 56.9% for WLI, BLI-bright, and LCI, respectively, being significantly higher in the LCI group than in the WLI group (P=0.03). No significant difference was observed between LCI and BLI-bright (P=0.71) or BLI-bright and WLI (P=0.09). The mean number of adenomas per patient was 0.82, 1.06, and 1.38 for WLI, BLI-bright, and LCI, respectively, with a significant difference between LCI and WLI (P=0.03). Withdrawal time did not differ between groups. A total of 102 adenomas were detected by WLI, 131 by BLI-bright, and 179 by LCI. LCI provided a higher rate of detection of adenomas ≤ 5 mm in size than WLI (P=0.02), with a borderline significance for a higher detection of sessile serrated adenomas (P=0.05). Nonpolypoid adenomas were more commonly located in the right colon segment and polypoid adenomas in the left colon segment, with a significant difference only between BLI-bright (P<0.01) and LCI (P=0.03).

Conclusions: Our findings show that LCI increases the detection of colorectal adenomas during colonoscopy.

1 Department of Endoscopy and Gastroenterology, Santa Casa de Caridade Hospital, Bagé, RS, Brazil.
2 Department of Gastroenterology and Endoscopy, Santa Casa Hospital, Porto Alegre, RS, Brazil.
3 Postgraduate Program in Principles of Surgery, Faculdade Evangélica do Paraná, Curitiba, PR, Brazil.

Diagnostic value of blue laser imaging combined with magnifying endoscopy for precancerous and early gastric cancer lesions.

Yang Zhenming 1, Shen Lei 1

Turk J Gastroenterol. 2019 Jun;30(6):549-556. doi: 10.5152/tjg.2019.18210.

Background / Aims: Blue laser imaging (BLI) is a new technique for detailed examination of upper gastrointestinal lesions. This study aimed to evaluate the diagnostic value of BLI combined with magnifying endoscopy for precancerous and early gastric cancer lesions.

Materials and methods: A total of 249 gastric lesions detected via conventional white light endoscopy (WLE) based on assessments of mucosal shape and color were included in this study. The accuracy of diagnosis of precancerous or early cancer lesions white light magnification alone, BLI-contrast magnification, and BLI-bright magnification was determined according to the VS criteria.

Results: For white light magnification alone, BLI-contrast magnification, and BLI-bright magnification, the concordance rates for lesions were 76.7%, 85.1%, and 86.7%, respectively, and the Kappa values were 0.571, 0.730, and 0.760, respectively. For the screening of high-grade intraepithelial neoplasia or early gastric cancer, the diagnostic sensitivities of white light magnification alone, BLI-contrast magnification, and BLI-bright magnification were 72.0%, 92.0%, and 92.0%, respectively; the specificities were 95.5%, 98.2%, and 99.1%, respectively; the consistencies were 93.2%, 97.6%, and 98.4%, respectively; and the Kappa values were 0.642, 0.871, and 0.911, respectively. For diagnoses of high-grade intraepithelial neoplasia or early gastric cancer, the concordance between endoscopic and pathological diagnosis was significantly higher for BLI-contrast and BLI-bright magnification than for white light magnification alone (p<0.05).

Conclusion: BLI combined with magnifying endoscopy may improve diagnostic accuracy for early gastric cancer and precancerous lesions.

1 Department of Gastroenterology, Renmin Hospital of Wuhan University, Wuhan, China

An International Study on the Diagnostic Accuracy of the Japan Narrow-Band Imaging Expert Team Classification for Colorectal Polyps Observed with Blue Laser Imaging.

Suzuki H.1, Yamamura T.2, Nakamura M.1, Hsu C.-M.3,4, Su M.-Y. 3,4, Chen T.-H. 3,4, Chiu C.-T. 3,4, Hirooka Y.2, Goto H.1

Digestion. 2019 Apr 12:1-8. doi: 10.1159/000499856. [Epub ahead of print]

Background: The Japan narrow-band imaging Expert Team (JNET) classification of colorectal polyps based on magnifying endoscopy is used in Japan, but not worldwide. The objective of this study was to clarify differences of diagnostic accuracy between JNET users in Japan and non-JNET users in other countries.

Methods: A total of 185 colorectal tumors were assessed. Six endoscopists (3 each from Japan and Taiwan) participated in the study. The Japanese endoscopists normally used the JNET classification and the Taiwanese endoscopists normally used the narrow-band imaging International Colorectal Endoscopic classification for diagnosis of colorectal tumors. After receiving a lecture on the JNET classification, they all observed one blue laser imaging magnified image per lesion and performed diagnosis based on the JNET classification.

Results: Diagnostic ability was equivalent for Type 1, Type 2A, and Type 2B. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value of Type 3 for deep submucosal invasive carcinoma was, respectively, 44.4, 98.3, 57.1, and 97.2% in Group J and 70.0, 94.7, 40.4, and 98.4% in Group T. The PPV for diagnosis of Type 3 with a high confidence was significantly higher in Group J than in Group T (81.8% [55.4-94.6] vs. 44.4% [33.6-50.9], p < 0.05).

Conclusions: The PPV for Type 3 differed between the 2 groups, suggesting the need to become familiar with differentiation between Type 2B and Type 3.

1 Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya, Japan
2 Department of Endoscopy, Nagoya University Hospital, Nagoya, Japan
3 Department of Gastroenterology and Hepatology, Linkou Chang Gung Memorial Hospital, Taoyuan, Taiwan
4 Department of Gastroenterology and Hepatology, Chang Gung University College of Medicine, Taoyuan, Taiwan

Objective evaluation of the visibility of colorectal lesions using eye tracking

Kumahara K1, Ikematsu H1, Shinmura K1, Murano T1, Inaba A1, Okumura K1, Nishihara K1, Sunakawa H1, Furue Y1, Ito R1, Sato D1, Minamide T1, Okamoto N1, Yamamoto Y1, Suyama M1, Takashima K1, Nakajo K1, Yoda Y1, Hori K1, Oono Y1, Yano T1.

Dig Endosc. 2019 Mar 14. doi: 10.1111/den.13397

Background and aim: To assess the visibility of colorectal lesions using blue laser imaging (BLI)-bright and linked-color imaging (LCI) with an eye-tracking system.

Methods: Eleven endoscopists evaluated 90 images of 30 colorectal lesions. The lesions were randomly selected. Three images of each lesion comprised white light imaging (WLI), BLI-bright, and LCI in the same position. Participants gazed at the images, and their eye movements were tracked by the eye tracker. We analyzed whether the participants could detect the lesion and how long they took to detect the lesion. We assessed the miss rate and detection time among the imaging modalities.

Results: One endoscopist was excluded, and 10 endoscopists were assessed. Overall, 12.6% of lesions were missed with WLI, 6.0% with BLI-bright, and 4.3% with LCI; the miss rate of BLI-bright and LCI was significantly lower than that of WLI (P < 0.01), with no significant difference between the former modalities (P = 0.54). Mean (± SD) detection times were 1.58 ± 1.60 s for WLI, 1.01 ± 1.21 s for BLI-bright, and 1.10 ± 1.16 s for LCI. Detection time for BLI-bright and LCI was significantly shorter than that for WLI (P < 0.0001), with no significant difference between the former modalities (P = 0.34). Regarding the miss rate and detection time between the expert and the non-experts, there was a significant difference with WLI but not with BLI-bright and LCI.

Conclusion: Blue laser imaging-bright and LCI improved the detection of colorectal lesions compared with WLI using an eye-tracking system.

1 Department of Gastroenterology and Endoscopy, National Cancer Center Hospital East, Chiba, Japan

Usefulness of close observation with non-magnified blue laser imaging for determining cold polypectomy indications.

Suzuki T1, Kitagawa Y1, Nankinzan R1, Takashiro H2, Hara T3, Yamaguchi T2.

Scand J Gastroenterol. 2018 Jul 24:1-5. doi: 10.1080/00365521.2018.1488181

Purpose: To examine the usefulness of non-magnified close observation with blue laser imaging (BLI) using a colonoscope with close observation capability in determining indications for cold polypectomy.

Methods: We conducted an image evaluation study on 100 consecutive colorectal lesions of 10 mm or less which were observed endoscopically without magnification using BLI mode prior to treatment. Two experts and two non-experts reviewed the images using the Japan NBI expert team (JNET) classification and the diagnostic accuracy was analyzed.

Results: The final pathological diagnoses of the 100 lesions were hyperplastic/sessile serrated polyp (HP/SSP), low grade dysplasia (LGD), high grade dysplasia (HGD) and deep submucosal invasive cancer (dSM), respectively, in 12, 79, 9 and 0 lesions. When JNET classification type 1 corresponds to HP/SSP; 2A to LGD; 2B to HGD; and 3 to dSM; the overall diagnostic accuracy was 84.3%. Accuracy was 90.5% for experts and 78.0% for non-experts. High confidence rate was 67.5% for experts and 48.0% for non-experts. In diagnostic accuracy for HGD, the sensitivity, specificity, PPV and NPV were, respectively, 77.8%, 98.9%, 87.5% and 97.8% for experts; and 66.6%, 92.3%, 46.2% and 96.6% for non-experts.

Conclusions: The diagnostic accuracy of unmagnified close observation with BLI using a colonoscope with close observation capability is similar to that reported for magnifying endoscopy and is useful in predicting the histological diagnosis of colorectal polyps of 10 mm or less although the effectiveness may be limited for non-experts. This modality is a potentially useful tool in deciding indications for cold polectomy.

1 Department of Endoscopy, Chiba Cancer Center, Chiba, Japan
2 Department of Gastroenterology, Chiba Cancer Center, Chiba, Japan
3 Hara Clinic