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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

Novel endoscopic findings as visualized by non-magnification endoscopy with linked color imaging are indicative of gastric intestinal metaplasia.

Min M1, Dong TH1, Liu Y1, Bi YL1, Ma CY1.

Chin Med J (Engl). 2019 Apr 5;132(7):782-788.

Background: Gastric intestinal metaplasia (GIM) is generally considered to be the main mucosal background for the development of gastric adenocarcinomas. Using linked color imaging (LCI), we noticed that the color pattern in areas of GIM was purple mixed with white on the epithelium with signs of mist that were detected by the non-magnifying LCI observation. We have termed this endoscopic finding “Purple in Mist” (PIM). The aim of this study was to investigate whether PIM could be a useful optical sign for predicting GIM.

Methods: We prospectively evaluated consecutive patients undergoing endoscopy for various indications. The endoscopist used the LCI system to carefully observe the gastric antrum, body and angulus. When a PIM was identified in the surface layer, targeted biopsies were subsequently taken from this part. If the suspected area had no PIM on the surface, targeted biopsies were also taken.

Results: Sixty-three consecutive patients were included in this study. The prevalence of intestinal metaplasia (IM) was 29/63 (46%). In PIM-positive patients, the prevalence of IM was 23/26 (89%). Of these patients, 146 biopsy specimens were included in this study. For the diagnosis of IM, compared to histological assessment, the LCI finding had an accuracy of 91.1% (95%CI: 86.5%-95.7%), a sensitivity of 89.8% (95%CI: 81.3%-98.3%), a specificity of 91.8% (95%CI: 86.3%-97.2%), a positive predictive value of 84.6% (95%CI: 74.8%-94.4%), and a negative predictive value of 94.7% (95%CI: 90.1%-99.2%).

Conclusions: A positive PIM finding in a suspicious lesion on LCI would complement LCI diagnosis of possible IM because of the positive predictive value of PIM. PIM could be a novel endoscopic marker for IM.

1 Department of Gastroenterology and Hepatology, Affiliated Hospital of Academy of Military Medical Sciences, Beijing 100071, China

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

Predictability of gastric intestinal metaplasia by patchy lavender color seen on linked color imaging endoscopy.

Chen H1, Wang H2, Wu X3, Liu Y3, Wu Q3, Lu Y3, Lin X3, Fan D3, Li C3.

Lasers Med Sci. 2019 Mar 22. doi: 10.1007/s10103-019-02775-8. [Epub ahead of print]

Abstract:We aimed to investigate the ability of linked color imaging (LCI) versus white light endoscopy (WLE) to detect gastric intestinal metaplasia (GIM). One hundred and seven participants who underwent upper gastrointestinal endoscopy were included. Under WLE endoscopy, biopsies were performed on any suspected abnormal mucosal changes. Under LCI endoscopy, we tested whether the specific color feature of patchy lavender color (PLC) pathologically indicated GIM. Biopsies were randomly performed in participants who had neither PLC nor suspected lesions. The detection abilities of LCI and WLE were assessed by comparison of histological and endoscopic findings. A total of 41 participants had histological GIM. The total diagnostic accuracy rate for GIM by LCI was 79.44%, higher than that of WLE (40.19%) (P < 0.001). Moreover, LCI with targeted biopsies showed a significantly increased ability to detect GIM (P < 0.001). PLC observed in the gastric mucosa on LCI can guide endoscopic biopsies and increase the detection rate of GIM. Thus, LCI could be a good tool for detecting GIM. ClinicalTrials.gov Identifier: ChiCTR-DDD-17011326).

1 Department of Gastrointestinal Endoscopy, Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases, the Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou 510655, Guangdong, People’s Republic of China
2 Department of Gastrointestinal Surgery, Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases, the Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou 510655, Guangdong, People’s Republic of China
3 Department of Gastrointestinal Surgery, the Eighth Affiliated Hospital, Sun Yat-sen University, Shenzhen 518033, Guangdong, People’s Republic of China

Utility of linked color imaging for endoscopic diagnosis of early gastric cancer.

Fujiyoshi T1, Miyahara R1, Funasaka K1, Furukawa K1, Sawada T2, Maeda K2, Yamamura T2, Ishikawa T1, Ohno E1, Nakamura M1, Kawashima H1, Nakaguro M3, Nakatochi M4, Hirooka Y2.

World J Gastroenterol. 2019 Mar 14;25(10):1248-1258. doi: 10.3748/wjg.v25.i10.1248.

Background: Linked color imaging (LCI) is a method of endoscopic imaging that emphasizes slight differences in red mucosal color.

Aim: To evaluate LCI in diagnostic endoscopy of early gastric cancer and to compare LCI and pathological findings.

Methods: Endoscopic images were obtained for 39 patients (43 lesions) with early gastric cancer. Three endoscopists evaluated lesion recognition with white light imaging (WLI) and LCI. Color values in Commission Internationale de l’Eclairage (CIE) 1976 Lab* color space were used to calculate the color difference (ΔE) between cancer lesions and non-cancer areas. After endoscopic submucosal dissection, blood vessel density in the surface layer of the gastric epithelium was evaluated pathologically. The identical region of interest was selected for analyses of endoscopic images (WLI and LCI) and pathological analyses.

Results: LCI was superior for lesion recognition (P < 0.0001), and ΔE between cancer and non-cancer areas was significantly greater with LCI than WLI (29.4 vs 18.6, P < 0.0001). Blood vessel density was significantly higher in cancer lesions (5.96% vs 4.15%, P = 0.0004). An a* cut-off of ≥ 24 in CIE 1976 Lab* color space identified a cancer lesion using LCI with sensitivity of 76.7%, specificity of 93.0%, and accuracy of 84.9%.

Conclusion: LCI is more effective for recognition of early gastric cancer compared to WLI as a result of improved visualization of changes in redness. Surface blood vessel density was significantly higher in cancer lesions, and this result is consistent with LCI image analysis.

1 Department of Gastroenterology Hepatology, Nagoya University Graduate School of Medicine, Nagoya 4668550, Japan
2 Department of Endoscopy, Nagoya University Hospital, Nagoya 4668560, Japan
3 Department of Pathology and Laboratory Medicine, Nagoya University Hospital, Nagoya 4668560, Japan
4 Division of Data Science, Data Coordinating Center, Department of Advanced Medicine, Nagoya University Hospital, Nagoya 4668560, Japan