Background and study aims: Linked color imaging (LCI) is a new image-enhanced endoscopy technique using a laser light source to enhance slight differences in mucosal color. The aim of this study was to compare the usefulness of LCI and conventional white light imaging (WLI) endoscopy for diagnosing Helicobacter pylori (H. pylori). Patients and methods: We retrospectively analyzed images from 60 patients examined with WLI and LCI endoscopy between October 2013 and May 2014. Thirty patients had H. pylori infections, and other thirty patients tested negative for H. pylori after eradication therapy. Four endoscopists evaluated the 2 types of images to determine which was better at facilitating a diagnosis of H. pylori infection. Results: H. pylori infection was identified with LCI by enhancing the red appearance of the fundic gland mucosa. The accuracy, sensitivity, and specificity for diagnosing H. pylori infection using WLI were 74.2 %, 81.7 %, and 66.7 %, respectively, while those for LCI were 85.8 %, 93.3 %, and 78.3 %, respectively. Thus, the accuracy and sensitivity for LCI were significantly higher than those for WLI (P = 0.002 and P = 0.011, respectively). The kappa values for the inter- and intraobserver variability among the 4 endoscopists were higher for LCI than for WLI. Conclusions: H. pylori infection can be identified by enhancing endoscopic images of the diffuse redness of the fundic gland using LCI. LCI is a novel image-enhanced endoscopy and is more useful for diagnosing H. pylori infection than is WLI.

Background and study aim This study aimed to assess the safety and feasibility of endoscopic submucosal dissection (ESD) using a scissors‐type knife with prophylactic closure using over‐the‐scope clip (OTSC) for superficial non‐ampullary duodenal epithelial tumors (SNADETs). Patients and methods Consecutive patients who underwent ESD for SNADETs >10 mm between January 2009 and July 2019 were retrospectively enrolled. We performed ESD using either a needle‐type knife (Flush Knife‐ESD) or a scissors‐type knife (Clutch Cutter‐ESD). Mucosal defects were prophylactically closed using three methods: conventional clip, laparoscopic closure, or OTSC. Results A total of 84 lesions were resected using the Flush Knife‐ESD and the Clutch Cutter‐ESD (37 and 47 patients, respectively), and conventional clip, laparoscopic closure, and OTSC for mucosal defect closure after ESD were applied in 13, 13, and 56 lesions, respectively. The R0 resection rate was significantly higher in the Clutch Cutter‐ESD than that in the Flush Knife‐ESD (97.9% vs 83.8%, respectively, P = 0.040). The intraoperative perforation rate was significantly lower in the Clutch Cutter‐ESD than in the Flush Knife‐ESD (0% vs 13.5%, respectively, P = 0.014). Complete closure rates of conventional clip, laparoscopic closure, and OTSC were 76.9%, 92.3%, and 98.2%, respectively (P = 0.021); and delayed perforation rates were 15.4%, 7.7%, and 1.8%, respectively (P = 0.092). Conclusions Endoscopic submucosal dissection using a scissors‐type knife with prophylactic OTSC closure is safe and feasible for the low‐invasive treatment of SNADETs.

Background Blue laser imaging (BLI) is a new image-enhanced endoscopy technique that utilizes a laser light source developed for narrow-band light observation. The aim of this study was to evaluate the usefulness of BLI for the diagnosis of early gastric cancer. Methods This single center prospective study analyzed 530 patients. The patients were examined with both conventional endoscopy with white-light imaging (C-WLI) and magnifying endoscopy with BLI (M-BLI) at Kyoto Prefectural University of Medicine between November 2012 and March 2015. The diagnostic criteria for gastric cancer using M-BLI included an irregular microvascular pattern and/or irregular microsurface pattern, with a demarcation line according to the vessel plus surface classification system. Biopsies of the lesions were taken after C-WLI and M-BLI observation. The primary end point of this study was to compare the diagnostic performance between C-WLI and M-BLI. Results We analyzed 127 detected lesions (32 cancers and 95 non-cancers). The accuracy, sensitivity, and specificity of M-BLI diagnoses were 92.1, 93.8, and 91.6 %, respectively. On the other hand, the accuracy, sensitivity, and specificity of C-WLI diagnoses were 71.7, 46.9, and 80.0 %, respectively.Conclusions M-BLI had improved diagnostic performance for early gastric cancer compared with C-WLI. These results suggested that the diagnostic effectiveness of M-BLI is similar to that of magnifying endoscopy with narrow-band imaging (M-NBI).

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Background/Aims. The aim of this study was to evaluate the endoscopic recognition of esophageal squamous cell carcinoma (ESCC) using four different methods (Olympus white light imaging (O-WLI), Fujifilm white light imaging (F-WLI), narrow band imaging (NBI), and blue laser imaging- (BLI-) bright). Methods. We retrospectively analyzed 25 superficial ESCCs that had been examined using the four different methods. Subjective evaluation was provided by three endoscopists as a ranking score (RS) of each image based on the ease of detection of the cancerous area. For the objective evaluation we calculated the color difference scores (CDS) between the cancerous and noncancerous areas with each of the four methods. Results. There was no difference between the mean RS of O-WLI and F-WLI. The mean RS of NBI was significantly higher than that of O-WLI and that of BLI-bright was significantly higher than that of F-WLI. Moreover, the mean RS of BLI-bright was significantly higher than that of NBI. Furthermore, in the objective evaluation, the mean CDS of BLI-bright was significantly higher than that of O-WLI, F-WLI, and NBI. Conclusion. The recognition of superficial ESCC using BLI-bright was more efficacious than the other methods tested both subjectively and objectively.

Endoscopic diagnosis of Helicobacter pylori (H. pylori) infection, the most common cause of gastric cancer, is very important to clarify high-risk patients of gastric cancer for reducing morbidity and mortality of gastric cancer. Recently, the Kyoto classification of gastritis was developed based on the endoscopic characteristics of H. pylori infection-associated gastritis for clarifying H. pylori infection status and evaluating risk factors of gastric cancer. Recently, magnifying endoscopy with narrow-band imaging (NBI) has reported benefits of the accuracy and reproducibility of endoscopic diagnosis for H. pylori-related premalignant lesions. In addition to NBI, various types of image-enhanced endoscopies (IEEs) are available including autofluorescence imaging, blue laser imaging, and linked color imaging. This review focuses on understanding the clinical applications and the corresponding evidences shown to improve the diagnosis of gastritis based on Kyoto classification using currently available advanced technologies of IEEs.

Background/Aims: Early-stage gastric cancer (EGC) is detected even after successful Helicobacter pylori eradication. This study is aimed at clarifying the clinicopathological characteristics of EGC detected after successful H. pylori eradication. Methods: This retrospective study analyzed 57 cases of EGC detected after successful H. pylori eradication and resected endoscopically at Kyoto Prefectural University of Medicine, between January 2009 and June 2014. Clinicopathological findings of 57 cases (H. pylori-eradicated group) were investigated, and compared with those in active H. pylori infection resected in the same period (H. pylori-positive group). Results: Most EGCs were detected in patients with severe atrophic mucosa, both in H. pylori-eradicated and H. pylori-positive groups, while the percentage of EGC detected in patients with mild atrophic mucosa gradually increased over time from successful eradication (H. pylori-positive: 7%, up to the fourth year since eradication: 11%, after the fifth year since eradication: 32%). The percentage of EGC detected in patients with mild atrophic mucosa after the fifth year since eradication was significantly higher than that in patients with active H. pylori infection (p = 0.004). Conclusion: After the fifth year following eradication, we should be alert to the incidence of EGC, irrespective of the severity of mucosal atrophic change.

Non-steroidal anti-inflammatory drugs (NSAIDs) have been implemented in clinical settings for a long time for their anti-inflammatory effects. With the number of NSAID users increasing, gastroenterological physicians and researchers have worked hard to prevent and treat NSAID-induced gastric mucosal injury, an effort that has for the large part being successful. However, the struggle against NSAID-induced mucosal damage has taken on a new urgency due to the discovery of NSAID-induced small intestinal mucosal injury. Although the main mechanism by which NSAIDs induce small intestinal mucosal injury has been thought to depend on the inhibitory effect of NSAIDs on cyclooxygenase (COX) activity, recent studies have revealed the importance of mitochondria-derived reactive oxygen species (ROS) production, which occurs independently of COX-inhibition. ROS production is an especially important factor in the increase of small intestinal epithelial cell permeability, an early stage in the process of small intestinal mucosal injury. By clarifying the precise mechanism, together with its clinical features using novel endoscopy, effective strategies for preventing NSAID-induced small intestinal damage, especially targeting mitochondria-derived ROS production, may be developed.