Background Visual inspection, lesion detection, and differentiation between malignant and benign features are key aspects of an endoscopist’s role. The use of machine learning for the recognition and differentiation of images has been increasingly adopted in clinical practice. This study aimed to establish convolutional neural network (CNN) models to automatically classify gastric neoplasms based on endoscopic images. Methods Endoscopic white-light images of pathologically confirmed gastric lesions were collected and classified into five categories: advanced gastric cancer, early gastric cancer, high grade dysplasia, low grade dysplasia, and non-neoplasm. Three pretrained CNN models were fine-tuned using a training dataset. The classifying performance of the models was evaluated using a test dataset and a prospective validation dataset. Results A total of 5017 images were collected from 1269 patients, among which 812 images from 212 patients were used as the test dataset. An additional 200 images from 200 patients were collected and used for prospective validation. For the five-category classification, the weighted average accuracy of the Inception-Resnet-v2 model reached 84.6 %. The mean area under the curve (AUC) of the model for differentiating gastric cancer and neoplasm was 0.877 and 0.927, respectively. In prospective validation, the Inception-Resnet-v2 model showed lower performance compared with the endoscopist with the best performance (five-category accuracy 76.4 % vs. 87.6 %; cancer 76.0 % vs. 97.5 %; neoplasm 73.5 % vs. 96.5 %; P  < 0.001). However, there was no statistical difference between the Inception-Resnet-v2 model and the endoscopist with the worst performance in the differentiation of gastric cancer (accuracy 76.0 % vs. 82.0 %) and neoplasm (AUC 0.776 vs. 0.865). Conclusion The evaluated deep-learning models have the potential for clinical application in classifying gastric cancer or neoplasm on endoscopic white-light images.

Introduction The eradication rates for Helicobacter pylori have decreased in Korea although the prevalence of this bacterium has also decreased. Antibiotic resistance is likely to be a crucial factor in H. pylori eradication success, and we therefore mapped these resistance patterns nationwide in Korea. Materials and Methods Five hundred and ninety adult subjects were prospectively enrolled from 2017 to 2018 from 15 centers across six geographic areas of Korea. A total of 580 biopsy tissues had been sampled from these patients during an upper endoscopy and were frozen at −80°C and delivered to a central laboratory. The agar dilution method was used to determine the minimum inhibitory concentration of amoxicillin, clarithromycin, metronidazole, tetracycline, ciprofloxacin, and levofloxacin for each H. pylori isolate. Results The culture success rate was 60.2% (349/580). Resistance rates against clarithromycin, metronidazole, amoxicillin, tetracycline, levofloxacin, and ciprofloxacin were 17.8%, 29.5%, 9.5%, 0%, 37.0%, and 37.0%, respectively. The geographic distribution of metronidazole and quinolone resistance was highly variable. Some subjects had multiple H. pylori strains in the antrum and body of the stomach and showed a heterogeneous resistance profile between these anatomic areas. The H. pylori multidrug resistance (MDR) rate was 25.2% (88/349) among amoxicillin, clarithromycin, metronidazole, tetracycline, and quinolone and 11.2% (39/349) among four of these major antibiotics except for quinolone. The Seoul and Chungcheong areas showed a relatively lower MDR rate. Conclusion The antibiotic resistance of H. pylori differs by drug and geographic area in Korea. Detailed nationwide antibiotic resistance mapping is needed to develop an effective H. pylori eradication strategy.

Background/AimsTo assess the therapeutic outcomes of endoscopic resection (ER) of early gastric cancer (EGC) with undifferentiated-type histology. MethodsCases of ER of EGC with undifferentiated-type histology in the Korean endoscopic submucosal dissection (ESD) registry database were identified and reviewed. The immediate outcomes, including en bloc resection, complete resection, and curative resection rates, and long-term outcomes, including recurrence and survival rates, were extracted and analyzed. ResultsFrom 2006 to 2015, 275 EGCs with undifferentiated-type histology from 275 patients were identified. The immediate outcomes were as follows: en bloc resection rate: 92.4%; complete resection rate: 80%; and curative resection rate: 36.4%. Compared to patients with lesions that were beyond the expanded indication, those with expanded indication lesions showed better therapeutic outcomes. There was no difference in immediate outcomes between patients with poorly differentiated adenocarcinoma (PDC) and signet ring cell carcinoma (SRC). However, compared to ER of SRC, ER of PDC had a stronger association with submucosal invasion (41.9% vs. 23.6%, p=0.003). With regard to long-term outcomes, there was no difference between lesions with curative and non-curative resections in the recurrence and mortality rates. These rates also did not differ between PDC and SRC (median follow up: 3.96 years). ConclusionsER confined to expanded indication lesions can be considered for treatment of EGC with undifferentiated-type histology.

The measurement of the hepatic venous pressure gradient (HVPG) for the estimation of portal hypertension (PH) in cirrhosis has some limitations, including its invasiveness. Hepatic vein arrival time (HVAT), as assessed by microbubble contrast-enhanced ultrasonography (CEUS), is negatively correlated with the histological grade of liver fibrosis because of the associated hemodynamic abnormalities. Anatomical and pathophysiological changes in liver microcirculation are the initial events leading to PH. However, the direct relationship between HVAT and PH has not been evaluated. The present study measured both HVPG and HVAT in 71 consecutive patients with compensated cirrhosis and analyzed the relationship between the two parameters (i.e., the derivation set). Results were validated in 35 compensated patients with cirrhosis at another medical center (i.e., the validation set). The derivation set had HVPG and HVAT values of 11.4 6 5.0 mmHg (mean 6 standard deviation; range, 2-23) and 14.1 6 3.4 seconds (range, 8.4-24.2), respectively; there was a statistically significant negative correlation between HVPG and HVAT (r 2 5 0.545; P < 0.001). The area under the receiver operating characteristic curve (AUROC) was 0.973 for clinically significant PH (CSPH; HVPG, !10 mmHg), and the sensitivity, specificity, positive predictive value, negative predictive value, and positive and negative likelihood ratios for CSPH for an HVAT cut-off value of 14 seconds were 92.7%, 86.7%, 90.5%, 89.7%, 6.95, and 0.08, respectively. In addition, a shorter HVAT was associated with worse Child-Pugh score (P < 0.001) and esophageal varices (P 5 0.018). In the validation set, there was also a significant negative correlation between HVAT and HVPG (r 2 5 0.538; P < 0.001), and AUROC 5 0.953 for CSPH. HVAT was significantly correlated with PH. These results indicate that measuring HVAT is useful for the noninvasive prediction of CSPH in patients with compensated cirrhosis. (HEPATOLOGY 2012;56:1053-1062 P ortal hypertension (PH) leads to serious complications, such as variceal bleeding, and is responsible for significant morbidity and mortality in patients with cirrhosis.1 In compensated cirrhosis in particular, the presence of clinically significant PH (CSPH) makes it possible to predict a poor prognosis, such as progression to decompensated cirrhosis or mortality. 2 This makes the precise grading of PH Abbreviations: AUROC, area under ROC curve; CEUS, contrast-enhanced ultrasonography; 95% CI, 95% confidence interval; CSPH, clinically significant

Serum pepsinogen assay (sPGA), which reveals serum pepsinogen (PG) I concentration and the PG I/PG II ratio, is a non-invasive test for predicting chronic atrophic gastritis (CAG) and gastric neoplasms. Although various cut-off values have been suggested, PG I ≤70 ng/mL and a PG I/PG II ratio of ≤3 have been proposed. However, previous meta-analyses reported insufficient systematic reviews and only pooled outcomes, which cannot determine the diagnostic validity of sPGA with a cut-off value of PG I ≤70 ng/mL and/or PG I/PG II ratio ≤3. We searched the core databases (MEDLINE, Cochrane Library, and Embase) from their inception to April 2018. Fourteen and 43 studies were identified and analyzed for the diagnostic performance in CAG and gastric neoplasms, respectively. Values for sensitivity, specificity, diagnostic odds ratio, and area under the curve with a cut-off value of PG I ≤70 ng/mL and PG I/PG II ratio ≤3 to diagnose CAG were 0.59, 0.89, 12, and 0.81, respectively and for diagnosis of gastric cancer (GC) these values were 0.59, 0.73, 4, and 0.7, respectively. Methodological quality and ethnicity of enrolled studies were found to be the reason for the heterogeneity in CAG diagnosis. Considering the high specificity, non-invasiveness, and easily interpretable characteristics, sPGA has potential for screening of CAG or GC.

Background/AimsFunctional dyspepsia (FD) is one of the most common gastrointestinal disorders, and FD imposes social and economic burden worldwide. The aim of this study is to identify the prevalence and risk factors of FD in health check-up population in tertiary centers in Korea.MethodsA nationwide multicenter prospective study was performed at 9 tertiary healthcare centers in Korea between September 2016 and June 2017. A total of 2525 subjects were investigated based on endoscopic findings and questionnaires with the Rome III criteria, and Helicobacter pylori serology (IgG).ResultsA total of 1714 subjects without organic disease were enrolled. The mean (± SD) age was 51.5 (± 12.7) years, and 917 patients (53.5%) were female. The proportion of H. pylori seropositivity was 51.0% (874/1714). The prevalence of FD was 10.3% (176/1714), and the subtypes of postprandial distress syndrome alone, epigastric pain syndrome alone, and postprandial distress syndrome-epigastric pain syndrome overlap were 4.8%, 3.0%, and 2.5%, respectively. Multivariate analysis showed that female gender (OR, 1.58; 95% CI, 1.14–2.21) and education below college level (OR, 1.45; 95% CI, 1.01–2.07) were related to FD. Multivariate analysis based on age 60 showed female gender as a significant (OR, 2.90; 95% CI, 1.06–7.94) factor in the group ≥60 years.ConclusionsThe prevalence of FD was 10.3% in the health check-up population in Korea. Female sex and education below college level were risk factors for FD. Female sex is a risk factor for FD in old age, underscoring the need for close attention in this age group.

Although the 7-day PPI-containing triple anti-H. pylori therapy is not inferior to the 14-day therapy, neither treatment duration provides acceptable eradication rate reaching 90% in per-protocol analysis. New combination regimen with higher efficacy should be developed as a first-line eradication therapy for H. pylori in Korea.

The aims of this study were to demonstrate the trends in seropositivity and the eradication therapy rate for Helicobacter pylori (H. pylori) over an 18-year period in an asymptomatic Korean population and to explore the factors associated with H. pylori seropositivity and its eradication therapy. In total, 23,770 subjects (aged 17–97 years) from a health examination center participated in this cross-sectional study from January 2016 to June 2017. Questionnaires that included questions about the participants’ H. pylori eradication therapy history were collected, and anti-H. pylori IgG antibodies were measured. Among the eligible subjects, the seroprevalence of H. pylori infection was 41.5%. The H. pylori eradication therapy rate increased continuously from 2005 (13.9%) to 2011 (19.3%) and then increased again until the first half of 2017 (23.5%) (P < 0.001). After exclusion of subjects with a history of gastric surgery, gastric cancer, H. pylori eradication therapy, or gastric symptoms, H. pylori seropositivity was 43.9% in 16,885 subjects, which was significantly lower than the seropositivities in 1998 (66.9%), 2005 (59.6%), and 2011 (54.4%). The risk factors associated with H. pylori seropositivity according to multivariable analysis were male sex (odds ratio (OR) 1.34, 95% confidence interval (CI): 1.23–1.46), medium educational level (OR 1.17, 95% CI: 1.05–1.31), medium household income level (OR 1.10, 95% CI: 1.03–1.19), and age of 60–69 years (OR 8.78, 95% CI: 6.41–11.85). The observed downward trend in H. pylori seroprevalence and increase in H. pylori eradication over the 18-year period will affect upper gastrointestinal disorders in South Korea.