Nakashima H¹, Kawahira H², Kawachi H³, Sakaki N¹

Gastric Cancer. 2020 May 7.

Background: Helicobacter pylori (H. pylori) eradication is required to reduce incidence related to gastric cancer. Recently, it was found that even after the successful eradication of H. pylori, an increased, i.e., moderate, risk of gastric cancer persists in patients with advanced mucosal atrophy and/or intestinal metaplasia. This study aimed to develop a computer-aided diagnosis (CAD) system to classify the status of H. pylori infection of patients into three categories: uninfected (with no history of H. pylori infection), currently infected, and post-eradication.

Methods: The CAD system was based on linked color imaging (LCI) combined with deep learning (DL). First, a validation dataset was formed for the CAD systems by recording endoscopic movies of 120 subjects. Next, a training dataset of 395 subjects was prepared to enable DL. All endoscopic examinations were recorded using both LCI and white-light imaging (WLI). These endoscopic data were used to develop two different CAD systems, one for LCI (LCI-CAD) and one for WLI (WLI-CAD) images.

Results: The diagnostic accuracy of the LCI-CAD system was 84.2% for uninfected, 82.5% for currently infected, and 79.2% for post-eradication status. Comparisons revealed superior accuracy of diagnoses based on LCI-CAD data relative based on WLI-CAD for uninfected, currently infected, and post-eradication cases. Furthermore, the LCI-CAD system demonstrated comparable diagnostic accuracy to that of experienced endoscopists with the validation data set of LCI.

Conclusions: The results of this study suggest the feasibility of an innovative gastric cancer screening program to determine cancer risk in individual subjects based on LCI-CAD.

1 Foundation for Detection of Early Gastric Carcinoma, 2-6-12 Nihombashikayabacho Chuo Ward, Tokyo 103-0025, Japan
2 Medical Simulation Center, Jichi Medical University,Tochigi, Japan
3 Department of Pathology, Cancer Institute Hospital Japanese, Foundation for Cancer Research, Tokyo, Japan

Sun X¹, Zhao L²

Gastroenterol Res Pract. 2020 Mar 31;2020:2105874. doi: 10.1155/2020/2105874. eCollection 2020.

Background and aims: Linked color imaging (LCI) helps screen and diagnose for early gastric cancer by color contrast in different mucosa. RGB (red, green, and blue) pixel brightness quantifies colors, which is relatively objective. Limited studies have combined LCI images with RGB to help screen for early gastric cancer (EGC). We aimed to evaluate the RGB pixel brightness characteristics of EGC and noncancer areas in LCI images.

Methods: We retrospectively reviewed early gastric cancer (EGC) patients and LCI images. All pictures were evaluated by at least two endoscopic physicians. RGB pixel brightness analysis of LCI images was performed in MATLAB software to compare the cancer with noncancer areas. Receiver operating characteristic (ROC) curve was analyzed for sensitivity, specificity, cut-off, and area under the curve (AUC).

Results: Overall, 38 early gastric cancer patients were enrolled with 38 LCI images. Pixel brightness of red, green, and blue in cancer was remarkably higher than those in noncancer areas (190.24 ± 37.10 vs. 160.00 ± 40.35, p < 0.001; 117.96 ± 33.91 vs. 105.33 ± 30.01, p = 0.039; 114.36 ± 34.88 vs. 90.93 ± 30.14, p < 0.001, respectively). Helicobacter plyori (Hp) infection was not relevant to RGB distribution of EGC. Whether the score of Kyoto Classification of Gastritis (KCG) is ≥4 or <4, the pixel brightness of red, green, and blue was not disturbed in both cancer and noncancer (p > 0.05). Receiver operating characteristic (ROC) curve for differentiating cancer from noncancer was calculated. The maximum area under the curve (AUC) was 0.767 in B/G, with a sensitivity of 0.605, a specificity of 0.921, and a cut-off of 0.97.

Conclusions: RGB pixel brightness was useful and more objective in distinguishing early gastric cancer for LCI images.

1 VIP Department and General Medicine Department, Beijing Hospital, National Center of Gerontology, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, China 100730
2 Department of Gastroenterology, Beijing Hospital, National Center of Gerontology, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, China 100730

Kanmura S¹, Tanaka A¹, Yutsudou K¹, Kuwazuru K¹, Komaki F¹, Komaki Y¹, Iwaya H¹, Arima S¹, Sasaki F¹, Tanoue S¹, Hashimoto S¹, Ido A¹.

Gastroenterol Res Pract. 2020 Mar 6;2020:3108690. doi: 10.1155/2020/3108690. eCollection 2020.

Ulcerative colitis (UC) is a chronic inflammatory bowel disease with unknown etiology. Recently, mucosal healing has emerged as an important therapeutic endpoint in UC. Linked color imaging (LCI) is a novel endoscopic system that enhances the color differences of the gastrointestinal mucosa. Our previous study emphasized the redness and yellowness of the lesion using LCI observation, which was useful for the evaluation of histological mucosal activity in UC. In this study, we aimed to evaluate the correlation between LCI observation and clinical relapse rate in UC patients. We retrospectively analyzed UC patients who underwent total colonoscopy between August 2016 and October 2018 at our facility with Mayo endoscopic scores of 0 or 1. We assessed the correlation between orange-like color lesion (defined as LCI-scarlet color lesions) and clinical relapse rate (requiring additional treatment for UC) during the 1-year follow-up period. Fifty-eight patients (22 female, 36 male; median age at diagnosis, 47.2 (18-80) years) who underwent colonoscopy were analyzed. During the 1-year follow-up period, clinical relapse was observed in 12 patients (20.1%) among which ten patients (83.3%) had an LCI-scarlet color lesions recognized by LCI. By contrast, 29 patients (63%) had no LCI-scarlet color lesions in the clinical remission group (n = 46). There was a significant difference in LCI-scarlet color between the clinical relapse and remission groups, remaining significantly associated with clinical relapse. LCI findings, including an orange-like color lesion, have diagnostic implications for predicting the risk of clinical relapse in UC during the 1-year follow-up period.

1 Digestive and Lifestyle Diseases, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan

Abe Y^1,2, Sasaki Y¹, Kon T¹, Ueno Y¹.

Intern Med. 2020 Mar 19. doi: 10.2169/internalmedicine.4381-19. [Epub ahead of print]

A 74-year-old man with dysphagia underwent screening endoscopy. Characteristic endoscopic findings of eosinophilic esophagitis (EoE), such as furrows, rings, or exudates, were not clearly observed, but edematous mucosa was vaguely detected on white light imaging (Picture 1a). These areas were highlighted as a beige color area on blue laser imaging (BLI) (Picture 1b) and a yellowish area on linked color imaging (LCI) (Picture 1c and 1d). Intense eosinophilic infiltration was observed in these image-enhanced areas histologically, but no similar observation was made in
the normal-appearing mucosa (Picture 2a, 2b). This patient was ultimately diagnosed with EoE. A meta-analysis reported that 15% of adult patients have no characteristic endoscopic manifestations of EoE (1). BLI and LCI are newly developed endoscopic imaging technologies on which the visibility of various organic lesions, such as inflammation or tumors, is enhanced (2). These technologies may improve the diagnostic accuracy of EoE by increasing the visibility of esophageal eosinophilia.

1 Department of Gastroenterology, Yamagata University Faculty of Medicine, Japan
2 Division of Endoscopy, Yamagata University Hospital, Japan

Suzuki T¹, Kitagawa Y¹, Nankinzan R¹, Yamaguchi T².

Endosc Int Open. 2020 Jan;8(1):E87-E91. doi: 10.1055/a-1035-9411. Epub 2020 Jan 8.

Background and study aims: Cold polypectomy is becoming popular for treatment of colon polyps due to its safety and convenience, but there is still the problem of tumor remnants. Because linked color imaging (LCI) improves polyp visibility, cold polypectomy under LCI is anticipated to reduce the tumor remnant rate. Therefore, we investigated the usefulness of this procedure.

Patients and methods: Fifty patients scheduled to undergo cold polypectomy for treatment of colon polyps < 10 mm and assumed to be adenomas were registered prospectively. After performing cold snare polypectomy (CSP) under LCI, biopsy was performed at two resection margin sites for each polyp to determine the tumor remnant rate.

Results: A total of 145 lesions were treated by CSP. Of the 139 lesions in which polyps were retrievable and diagnosed as adenomas pathologically, one lesion was recognized as a remnant adenoma on biopsy (remnant rate: 0.7 % [95 % CI: 0.0-4.4]). This remnant rate was extremely low. Treatment results were extremely promising given that en bloc resection, post-procedure bleeding, and perforation rates were 100 %, 0 %, and 0 %, respectively.

Conclusion:  Cold snare polypectomy under LCI may be an effective treatment method capable of reducing the tumor remnant rate. This trial was approved by our Institutional Ethics Committee and registered at the University Hospital Medical Information Network (UMIN 000033690).

1 Department of Endoscopy, Chiba Cancer Center, Chiba, Japan
2 Department of Gastroenterology, Chiba Cancer Center, Chiba, Japan