Reading of small bowel capsule endoscopy after frame reduction using an artificial intelligence algorithm.

OBJECTIVES: Poorly visualized images that appear during small bowel capsule endoscopy (SBCE) can confuse the interpretation of small bowel lesions and increase the physician's workload. Using a validated artificial intelligence (AI) algorithm that can evaluate the mucosal visualization, we aimed to assess whether SBCE reading after the removal of poorly visualized images could affect the diagnosis of SBCE. METHODS: A study was conducted to analyze 90 SBCE cases in which a small bowel examination was completed. Two experienced endoscopists alternately performed two types of readings. They used the AI algorithm to remove poorly visualized images for the frame reduction reading (AI user group) and conducted whole frame reading without AI (AI non-user group) for the same patient. A poorly visualized image was defined as an image with < 50% mucosal visualization. The study outcomes were diagnostic concordance and reading time between the two groups. The SBCE diagnosis was classified as Crohn's disease, bleeding, polyp, angiodysplasia, and nonspecific finding. RESULTS: The final SBCE diagnoses between the two groups showed statistically significant diagnostic concordance (k = 0.954, p < 0.001). The mean number of lesion images was 3008.5 ± 9964.9 in the AI non-user group and 1401.7 ± 4811.3 in the AI user group. There were no cases in which lesions were completely removed. Compared with the AI non-user group (120.9 min), the reading time was reduced by 35.6% in the AI user group (77.9 min). CONCLUSIONS: SBCE reading after reducing poorly visualized frames using the AI algorithm did not have a negative effect on the final diagnosis. SBCE reading method integrated with frame reduction and mucosal visualization evaluation will help improve AI-assisted SBCE interpretation.

Taking Oral Sulfate Tablets with Simethicone for Bowel Preparation Leads to Higher Adenoma Detection Rate than Polyethylene Glycol: A Propensity Score Analysis.

BACKGROUND: Efficient bowel preparation is essential for preventing colorectal cancer by improving endoscopic adenoma detection. Tablet for bowel preparation containing sulfate salts, OSTs (oral sulfate tablets), has been developed and it is gaining more popularity. However, its efficacy compared to standard preparation agent, PEG-AA (polyethylene glycol), has not been well discovered. We assessed the efficacy of PEG and OSTs using a real-time clinical data warehouse (CDW) model. METHODS: We performed a propensity score-matched (PSM) analysis of consecutive adult patients undergoing colonoscopy who received PEG-AA or OSTs prior to colonoscopy at a tertiary academic hospital. The endoscopic records of 992 adult patients were retrospectively analyzed. The clinical data warehouse collected data including bowel preparation, insertion time, observation time, and the detection of polyps and adenomas. Multivariate regression analysis was performed to reveal the factors associated with endoscopic outcomes. RESULTS: Among 992 patients included in the study, 770 and 222 patients received PEG-AA and OSTs, respectively. Among the propensity score-matched population (n = 1897), OSTs resulted in better bowel cleansing quality (8.16 vs 7.84, p = 0.014) and a higher adenoma detection rate (38.6% vs 27.1%, p = 0.003). Using PEG-AA, older age, inadequate bowel preparation (BBPS score < 6) and endoscopy by fellows were found to be factors associated with poor adenoma detection. In the elderly over 65 years of age, a significant difference in cleansing quality between the two groups (7.21 vs 8.19, p < 0.001) was found, but its impact on ADR was not prominent (49.5% vs 45.4%, p = 0.653). CONCLUSIONS: OSTs with simethicone achieved better endoscopic cleanliness, improving adenoma detection rate compared to the conventional PEG-AA protocol. The synergistic effect of both the convenience of taking tablets and the reduction of intraluminal bubble by adjunctive simethicone improves the clinical efficacy of colonoscopy.

The effect of menopausal hormone therapy on gastrointestinal cancer risk and mortality in South Korea: a population-based cohort study.

BACKGROUND: The effect of menopausal hormone therapy (MHT) on gastrointestinal (GI) cancers is controversial, and no research has been conducted in the East. This study investigates the association between MHT and GI cancer risks in South Korea. METHODS: A prescription-based cohort study was conducted using the NHIS Sample Cohort (2002-2013) of Korea. We used 1:5 propensity score matching, and 22,577 MHT users and 111,113 non-users were selected. Kaplan-Meier survival curves with log-rank tests were used. Cox proportional hazard models were used to estimate hazard ratios (HR) with 95% confidence intervals (CI). Landmark analysis was used to determine dose-response relationship. RESULTS: The median follow-up was 79.6 of months. Kaplan-Meier survival curve showed less frequent GI cancer diagnoses in MHT users compared to non-users (0.13 vs. 0.16 per 100,000 person-years). Menopausal hormone therapy was associated with decreased incidence of GI cancer (HR = 0.809, 95%CI = 0.691-0.946) and colorectal cancer (CRC) (HR = 0.757, 95%CI = 0.577-0.995). Gastric cancer (GC) incidence showed marginal significance (HR = 0.787, 95%CI = 0.605-1.023). The mortality from GI cancer was lower in MHT users than in non-users (HR = 0.737, 95%CI = 0.547-0.993). The relationship between MHT and GI cancer was stronger with increasing MHT dose in terms of both incidence (Ptrend = 0.0002) and mortality (Ptrend = 0.0064). CONCLUSIONS: The association between MHT use and reduced risks of GI cancers was attributed to CRC and GC and showed a dose-response relationship in a population-based cohort study.

Complications of common bile duct stones: A risk factors analysis.

BACKGROUND: The latest guidelines recommended that common bile duct stones (CBDSs) should be removed, preferably endoscopically, regardless of the presence of symptoms or complications. However, the removal of CBDSs may not be feasible in very old patients or those with co-morbidities. In these cases, it is important to understand the risk factors for the development of CBDSs-related complications to decide whether or not to treat high-risk patients. Herein, we aimed to identify the risk factors for the development of complications after the diagnosis of CBDSs. METHODS: The medical records of patients with CBDSs between October 2005 and September 2019 were retrospectively analyzed. All patients with radiologically-diagnosed CBDSs, including those who received treatment and those who did not, were analyzed. RESULTS: A total of 634 patients were included and 95 (15.0%) patients had CBDS-related complications during the mean follow-up period of 32.6 months. Forty-four (6.9%) high-risk patients remained asymptomatic and did not receive treatment during the follow-up period. In multivariate analyses, size of CBDSs ≥ 5 mm and no treatment within 30 days were independent risk factors for the development of complications. The spontaneous passage of CBDSs was proved radiologically in 9 out of 81 (11.1%) patients within 30 days. CONCLUSIONS: It is recommended treating CBDSs within 30 days from the diagnosis, even in high-risk patients, especially if the size is larger than 5 mm.

Effect of Helicobacter pylori infection and its eradication on gastric regenerating atypia in 22 133 subjects.

BACKGROUND AND AIM: The aim of this study was to identify factors affecting persistent gastric regenerating atypia and determine the effect of Helicobacter pylori eradication on the course of this lesion. METHODS: In cross-sectional setting, comprehensive health check-up subjects who underwent both endoscopy and H. pylori test from 2001 to 2009 were included. The association between H. pylori and gastric regenerating atypia was evaluated. In cohort setting, patients with regenerating atypia who underwent H. pylori test from 2001 to 2013 were included. Factors affecting positive pathology (persistent regenerating atypia or new development of neoplasm) in patients with regenerating atypia at baseline were investigated. RESULTS: In cross-sectional setting, regenerating atypia was observed in 1.1% (241/22 133). H. pylori infection was associated with gastric regenerating atypia (adjusted odds ratio, 1.47; 95% confidence interval [CI], 1.12-1.91). In cohort setting, 310 patients with regenerating atypia were finally eligible. Positive pathology rate during follow up was 16.1% (15/93) in the persistent infection group, 2.8% (3/106) in successful eradication group, and 4.5% (5/111) in baseline H. pylori-negative group. Persistent H. pylori infection increased the risk of positive pathology (adjusted risk ratio [RR], 7.18; 95% CI, 1.95-26.48) compared to H. pylori eradication group. Persistent H. pylori infection increased the risk of regenerative atypia (adjusted RR, 5.70; 95% CI, 1.46-22.17) and new neoplasm (adjusted RR, 10.74; 95% CI, 1.10-105.17) compared to baseline negative H. pylori. CONCLUSIONS: H. pylori infection is an independent risk factor for gastric regenerating atypia. Eradication of H. pylori seems helpful for regression of regenerating atypia.

Effect of Helicobacter pylori eradication and high-density lipoprotein on the risk of de novo gastric cancer development.

BACKGROUND AND AIMS: The effect of Helicobacter pylori eradication on de novo gastric cancer is controversial, although meta-analyses suggest a reduction in gastric cancer after eradication. The effect of high-density lipoprotein (HDL) on gastric cancer has been rarely reported. METHODS: In this large retrospective cohort study, participants underwent endoscopy and H pylori testing from 2003 to 2011 and underwent follow-up endoscopy and H pylori testing until 2013. H pylori infection was detected using a rapid urease test or histologic test. The H pylori eradication group was defined as successful eradication, whereas the H pylori persistent group was defined as noneradication or eradication failure. The risk of cancer was measured with hazard ratios (HRs) and 95% confidence intervals (CIs). RESULTS: Among 10,328 healthy subjects (5951 men; mean age, 48.7 years), 31 gastric cancers were detected during a median follow-up of 5.5 years. De novo gastric cancer developed in 21 of 3508 subjects (.6%) in the noneradication group, 4 of 2050 subjects (.2%) in the successful eradication group, and 6 of 4770 participants (.13%) in the absence of H pylori group. In the adjusted analysis, H pylori eradication decreased de novo gastric cancer risk (HR, .29; 95% CI, .10-.86) compared with the persistent group. The risk of de novo gastric cancer in absence of H pylori was also much lower compared with the persistent group (HR, .24; 95% CI, .09-.60). Low serum HDL increased the risk of de novo gastric cancer (HR, 2.67; 95% CI, 1.14-6.16). CONCLUSIONS: Successful H pylori eradication reduced de novo gastric cancer, whereas low HDL increased its risk.

Helicobacter pylori infection is an independent risk factor for colonic adenomatous neoplasms.

PURPOSE: Helicobacter pylori infection is considered to have a positive association with colorectal neoplasms. In this study, we evaluated the association between H. pylori infection and colorectal adenomas, based on the characteristics of these adenomas in Korea, where the prevalence of H. pylori infection is high and the incidence of colorectal cancer continues to increase. METHODS: The study cohort consisted of 4,466 subjects who underwent colonoscopy and esophagogastroduodenoscopy during screening (1,245 colorectal adenomas vs. 3,221 polyp-free controls). We compared the rate of H. pylori infection between patients with adenoma and polyp-free control cases, using multivariable logistic regression analysis. RESULTS: The overall rate of positive H. pylori infection was higher in adenoma cases than in polyp-free control cases (55.0 vs. 48.5%, p < 0.001). The odds ratio (OR) of positive H. pylori infection in patients with adenoma compared to polyp-free controls was 1.28 (95% CI 1.11-1.47). The positive association of H. pylori infection with colorectal adenomas was more prominent in advanced adenomas (OR 1.84, 95% CI 1.25-2.70) and multiple adenomas (OR 1.72, 95% CI 1.26-2.35). Based on the location of these adenomas, the OR was significant only in patients with colonic adenomas (OR 1.31, 95% CI 1.13-1.52) and not in those with rectal adenoma (OR 0.85, 95% CI 0.58-1.24). CONCLUSION: Helicobacter pylori infection is an independent risk factor for colonic adenomas, especially in cases of advanced or multiple adenomas, but not for rectal adenomas.

Visceral Adipose Tissue Volume and the Occurrence of Colorectal Adenoma in Follow-up Colonoscopy for Screening and Surveillance.

Whether obesity accelerates adenoma recurrence is not yet clear; therefore, we analyzed the risk factors for adenoma occurrence at follow-up colonoscopy, with a focus on visceral adiposity. In total, 1516 subjects underwent index colonoscopy, computed tomography, and questionnaire assessment from February to May 2008; 539 subjects underwent follow-up colonoscopy at the National Cancer Center at least 6 mo after the index colonoscopy. The relationships between the presence of adenoma at follow-up colonoscopy and anthropometric obesity measurements, including body mass index (BMI), waist circumference (WC), visceral adipose tissue (VAT) volume, and subcutaneous adipose tissue (SAT) volume, were analyzed. 188 (34.9%) had adenomatous polyps at follow-up colonoscopy. Multivariate analysis revealed that VAT volume ≥ 1000 cm3 and BMI ≥ 30 kg/m2 were related to the presence of adenoma at follow-up colonoscopy (VAT volume 1000-1500 cm3: odds ratio [OR] = 2.13(95% confidence interval, CI = 1.06-4.26), P = 0.034; VAT volume ≥ 1000 cm3: OR = 2.24(95% CI = 1.03-4.88), P = 0.043; BMI ≥ 30 kg/m2: OR = 4.22(95% CI = 1.12-15.93), P = 0.034). In contrast, BMI 25-29.9 kg/m2, SAT volume, and WC were not associated with the presence of adenoma at follow-up colonoscopy. In conclusion, excess VAT can contribute to the development and growth of new colorectal adenomas, and is a better predictor of colorectal adenoma occurrence at follow-up colonoscopy than BMI, WC, and SAT volume.

OLGA and OLGIM stage distribution according to age and Helicobacter pylori status in the Korean population.

BACKGROUND: The Operative Link for Gastritis Assessment (OLGA) and the Operative Link on Gastric Intestinal Metaplasia Assessment (OLGIM) staging systems have been suggested to provide risk assessment for gastric cancer. This study aimed to evaluate the distribution of OLGA and OLGIM staging by age and Helicobacter pylori status. MATERIALS AND METHODS: We studied 632 subjects who underwent esophagogastroduodenoscopy for gastric cancer screening. Helicobacter pylori status and histologic changes were assessed using the updated Sydney system. Stage III and IV OLGA or OLGIM stages were considered as high-risk stages. RESULTS: The rate of H. pylori infection was 59.0% (373/632). Overall, the proportion of high OLGA and OLGIM stages was significantly increased with older age (p < .001 for both). Old age (OR = 5.17, 6.97, and 12.23 for ages in the 40's, 50's, and 60's, respectively), smoking (OR = 2.54), and H. pylori infection (OR = 8.46) were independent risk factors for high-risk OLGA stages. These risk factors were the same for high-risk OLGIM stages. In the H. pylori-positive subgroup, the proportion of high-risk OLGA stages was low (6.9%) before the age of 40, but increased to 23.0%, 29.1%, and 41.1% for those in their 40s, 50s, and 60s, respectively (p < .001). High-risk OLGIM stages showed a similar trend of 2.8% before the age of 40 and up to 30.1% for those in their 60s. High-risk OLGA and OLGIM stages were uncommon in the H. pylori-negative group, with a respective prevalence of 10.3% and 3.4% even among those in their 60s. CONCLUSIONS: Because high-risk OLGA and OLGIM stages are uncommon under the age of 40, H. pylori treatment before that age may reduce the need for endoscopic surveillance for gastric cancer.

Reduced risk of gastrointestinal bleeding associated with eupatilin in aspirin plus acid suppressant users: nationwide population-based study.

BACKGROUND/AIMS: Mucoprotective agents, such as eupatilin, are often prescribed to prevent gastrointestinal (GI) bleeding in addition to an acid suppressant despite the absence of a large-scale study. We evaluated the additional effect of eupatilin on the prevention of GI bleeding in both the upper and lower GI tract in concomitant aspirin and acid suppressant users using the nationwide database of national claims data from the Korean National Health Insurance Service (NHIS). METHODS: An aspirin cohort was constructed using the NHIS claims data from 2013 to 2020. Patients who manifested with hematemesis, melena, or hematochezia were considered to have GI bleeding. A Cox proportional hazards regression model was used to determine the risk factors for GI bleeding associated with the concomitant use of GI drugs and other covariates among aspirin users. RESULTS: Overall, a total of 432,208 aspirin users were included. The concurrent use of an acid suppressant and eupatilin (hazard ratio [HR] = 0.85, p = 0.016, vs. acid suppressant only) was a statistically significant preventive factor for GI bleeding. Moreover, a more than 3-month duration (HR = 0.88, p = 0.030) of acid suppressant and eupatilin prescription (vs. acid suppressant only) was a statistically significant preventive factor for GI bleeding. CONCLUSION: Eupatilin administration for ≥ 3 months showed additional preventive effect on GI bleeding in concomitant aspirin and acid suppressant users. Thus, cotreatment with eupatilin with a duration of 3 months or longer is recommended for reducing GI bleeding among aspirin plus acid suppressant users.

The combined use of anti-peptic agents is associated with an increased risk of osteoporotic fracture: a nationwide case-control study.

BACKGROUND/AIMS: Long-term use of acid suppressants such as proton pump inhibitors (PPIs) and histamine 2 receptor antagonist (H2RA) has been associated with the risk of osteoporotic fracture. Acid suppressants and muco-protective agents (MPAs) are often used together as anti-ulcer agents. We evaluated the association between the risk of osteoporotic fracture and the combined use of these anti-peptic agents. METHODS: A population-based case-control study was conducted by analyzing the Korean National Health Insurance Data from 2014 to 2020. Patients who had been prescribed anti-peptic agents, such as PPI, H2RA, or MPA, were included. Considering the incidence of osteoporotic fractures, the case group (n = 14,704) and control group (n = 58,816) were classified by 1:4 matching based on age and sex. RESULTS: The use of all types of anti-peptic agents was associated with an increased risk of osteoporotic fractures (PPI: hazard osteoratio [HR], 1.31; H2RA: HR, 1.44; and MPA: HR, 1.33; all p < 0.001). Compared to PPI alone, the combined use of "PPI and H2RA" (HR, 1.58; p = 0.010) as well as "PPI, H2RA, and MPA" (HR, 1.71; p = 0.001) was associated with an increased risk of osteoporotic fracture. However, compared with PPI alone, "MPA and PPI or H2RA" was not associated with an increased risk of osteoporotic fracture. CONCLUSION: This study found that the combined use of "PPI and H2RA" was associated with a higher risk of osteoporotic fractures. In cases where deemed necessary, the physicians may initially consider prescribing the combination use of MPA.

Efficacy and safety of three-dimensional magnetically assisted capsule endoscopy for upper gastrointestinal and small bowel examination.

BACKGROUND: Magnetically assisted capsule endoscopy (MACE) showed the feasibility for upper gastrointestinal examination. To further enhance the performance of conventional MACE, it is necessary to provide quality-improved and three-dimensional images. The aim of this clinical study was to determine the efficacy and safety of novel three-dimensional MACE (3D MACE) for upper gastrointestinal and small bowel examination at once. METHODS: This was a prospective, single-center, non-randomized, and sequential examination study (KCT0007114) at Dongguk University Ilsan Hospital. Adult patients who visited for upper endoscopy were included. The study protocol was conducted in two stages. First, upper gastrointestinal examination was performed using 3D MACE, and a continuous small bowel examination was performed by conventional method of capsule endoscopy. Two hours later, an upper endoscopy was performed for comparison with 3D MACE examination. The primary outcome was confirmation of major gastric structures (esophagogastric junction, cardia/fundus, body, angle, antrum, and pylorus). Secondary outcomes were confirmation of esophagus and duodenal bulb, accuracy for gastric lesions, completion of small bowel examination, 3D image reconstruction of gastric lesion, and safety. RESULTS: Fifty-five patients were finally enrolled. The examination time of 3D MACE was 14.84 ± 3.02 minutes and upper endoscopy was 5.22 ± 2.39 minutes. The confirmation rate of the six major gastric structures was 98.6% in 3D MACE and 100% in upper endoscopy. Gastric lesions were identified in 43 patients during 3D MACE, and 40 patients during upper endoscopy (Sensitivity 0.97). 3D reconstructed images were acquired for all lesions inspected by 3D MACE. The continuous small bowel examination by 3D MACE was completed in 94.5%. 3D MACE showed better overall satisfaction (3D MACE 9.55 ± 0.79 and upper endoscopy 7.75 ± 2.34, p<0.0001). There were no aspiration or significant adverse event or capsule retention in the 3D MACE examination. CONCLUSIONS: Novel 3D MACE system is more advanced diagnostic modality than the conventional MACE. And it is possible to perform serial upper gastrointestinal and small bowel examination as a non-invasive and one-step test. It would be also served as a bridge to pan-endoscopy.

Osteoporosis Is Associated with an Increased Risk of Colorectal Neoplasms Regardless of Sex: Nationwide Population-Based Cohort Study.

Vitamin D may have anticancer effects against colorectal cancer (CRC). Bone mineral density (BMD) reflects the long-term vitamin D status. This study investigated the association between osteoporosis and colorectal neoplasms (CRN). The data were obtained from the National Health Insurance Service sample cohort, which included 60,386 osteoporosis patients and 8224 controls who underwent BMD in 2002-2019. The logistic regression models included age, sex, income level, and comorbidity. Sensitivity tests were performed using the data from the National Health Screening Program. In total, 7706 (11.2%) patients were diagnosed with CRN, and the proportion was significantly higher in osteoporosis patients than in controls (11.7% vs. 8.1%). In the multivariate analysis, osteoporosis was associated with an increased risk of CRN (odds ratio (OR) = 1.91, 95% confidence interval = 1.75-2.09, p < 0.0001), which was significant for both colorectal adenomas and CRC (OR = 1.88 and 1.83, respectively). A subgroup analysis by sex revealed a significant association between osteoporosis and CRN in both women and men (OR = 2.06 and 1.66, respectively). The sensitivity tests revealed results similar to those of the original dataset. In conclusion, osteoporosis is significantly associated with CRN risk in both sexes. In high-risk patients with low BMD, appropriate screening for CRN and vitamin D supplementation are required, regardless of sex.

Association between eupatilin and reduction in small bowel bleeding in aspirin users and aspirin plus acid suppressant users.

BACKGROUND/AIMS: Capsule endoscopy (CE) has shown that low-dose aspirin occasionally causes small bowel (SB) bleeding. We herein evaluated the protective effects of mucoprotective agents (MPAs) on SB bleeding in aspirin users using the nationwide database of claims data from the National Health Insurance Service (NHIS). METHODS: As CE is an insured procedure, we constructed an aspirin-SB cohort using NHIS claims data, with a maximum follow- up period of 24 months. Patients with anemia, melena, or hematochezia that occurred within 4 weeks before and after performing CE were suspected to have SB bleeding. A Cox proportional hazards regression model was used to determine the risk factors for SB bleeding. Subgroup analyses were conducted among patients who used acid suppressants, such as proton pump inhibitors (PPIs) and histamine-2 receptor antagonists. RESULTS: A total of 15,542 aspirin users were included. Anticoagulant use (hazard ratio [HR], 3.22), high Charlson comorbidity index score (≥ 2) (HR, 3.54), and PPI use (HR, 2.85) were significantly associated with SB bleeding, whereas eupatilin use (HR, 0.35) was a preventive factor. SB bleeding occurred more frequently in concurrent users of acid suppressants than in nonusers (1.3% vs. 0.5%). Subgroup analysis revealed that eupatilin significantly reduced the risk of SB bleeding in aspirin users with concurrent use of acid suppressants (HR, 0.23 vs. 2.55). CONCLUSION: Eupatilin was associated with a reduced risk of SB bleeding in both aspirin users and those with concomitant use of acid suppressants. Eupatilin use should be considered for aspirin users, especially for those concomitantly taking acid suppressants.

A practical approach for small bowel bleeding.

Gastrointestinal (GI) bleeding is one of the most common conditions among patients visiting emergency departments in Korea. GI bleeding is divided into upper and lower GI bleeding, according to the bleeding site. GI bleeding is also divided into overt and occult GI bleeding based on bleeding characteristics. In addition, obscure GI bleeding refers to recurrent or persistent GI bleeding from a source that cannot be identified after esophagogastroduodenoscopy or colonoscopy. The small intestine is the largest part of the alimentary tract. It extends from the pylorus to the cecum. The small intestine is difficult to access owing to its long length. Moreover, it is not fixed to the abdominal cavity. When hemorrhage occurs in the small intestine, the source cannot be found in many cases because of the characteristics of the small intestine. In practice, small-intestinal bleeding accounts for most of the obscure GI bleeding. Therefore, in this review, we introduce and describe systemic approaches and examination methods, including video capsule endoscopy and balloon enteroscopy, that can be performed in patients with suspected small bowel bleeding in clinical practice.

The Advent of Domain Adaptation into Artificial Intelligence for Gastrointestinal Endoscopy and Medical Imaging.

Artificial intelligence (AI) is a subfield of computer science that aims to implement computer systems that perform tasks that generally require human learning, reasoning, and perceptual abilities. AI is widely used in the medical field. The interpretation of medical images requires considerable effort, time, and skill. AI-aided interpretations, such as automated abnormal lesion detection and image classification, are promising areas of AI. However, when images with different characteristics are extracted, depending on the manufacturer and imaging environment, a so-called domain shift problem occurs in which the developed AI has a poor versatility. Domain adaptation is used to address this problem. Domain adaptation is a tool that generates a newly converted image which is suitable for other domains. It has also shown promise in reducing the differences in appearance among the images collected from different devices. Domain adaptation is expected to improve the reading accuracy of AI for heterogeneous image distributions in gastrointestinal (GI) endoscopy and medical image analyses. In this paper, we review the history and basic characteristics of domain shift and domain adaptation. We also address their use in gastrointestinal endoscopy and the medical field more generally through published examples, perspectives, and future directions.

Cancer risk in patients with Peutz-Jeghers syndrome in Korea: a retrospective multi-center study.

BACKGROUND/AIMS: There have been little research on the cancer risks of patients with Peutz-Jeghers syndrome (PJS) in Korea. We aimed to investigate the clinical features of PJS patients and their cancer incidence rate. METHODS: Patients with PJS from nine medical centers were enrolled. In those patients diagnosed with cancer, data obtained included the date of cancer diagnosis, the tumor location, and the cancer stage. The cumulative risks of gastrointestinal cancers and extra-gastrointestinal cancers were calculated using the Kaplan-Meier method. RESULTS: A total of 96 PJS patients were included. The median age at diagnosis of PJS was 23.4 years. Cancer developed in 21 of the 96 patients (21.9%). The age of PJS diagnosis was widely distributed (0.9 to 72.4 years). The most common cancers were gastrointestinal cancer (n = 12) followed by breast cancer (n = 6). The cumulative lifetime cancer risk was calculated to be 62.1% at age 60. The cumulative lifetime gastrointestinal cancer risk was 47.1% at age 70. The cumulative lifetime extra- gastrointestinal cancer risk was 40.3% at age 60. CONCLUSION: PJS onset may occur at any age and the risks of gastrointestinal and extra-gastrointestinal cancer are high. Thorough surveillance of PJS patients for malignancies is vital.

Association of the interval between endoscopies with gastric cancer stage at diagnosis in a region of high prevalence.

BACKGROUND: Endoscopy screening in high-risk populations may reduce gastric cancer mortality by detecting cancer earlier. We evaluated the association between the interval between upper gastrointestinal endoscopies and the gastric cancer stage at diagnosis in patients from a region of high prevalence. METHODS: The study cohort consisted of 2485 patients diagnosed with gastric adenocarcinoma. We evaluated the effect on cancer stage of the interval between the endoscopy that was diagnostic for gastric cancer and the endoscopy preceding it. Patients were stratified into 7 groups: 1-, 2-, 3-, 4-, 5-, >5-year intervals and those who were never screened. RESULTS: The risk of higher cancer stage at diagnosis increased by 23% per increase in interval length (odds ratio = 1.23, 95% confidence interval [CI] = 1.19-1.28). Compared to the never-screened, the odds ratio of having a higher stage of cancer decreased gradually from 0.53 (95% CI = 0.41-0.69) in the >5-year interval group to 0.31 (95% CI = 0.24-0.40) in the 1-year interval group. Compared to the 1-year interval group, the risk of advanced gastric cancer was increased in the 4- and 5-year, but not the 2- and 3-year, interval groups. However, patients with a family history of gastric cancer were more likely to have a higher stage at diagnosis if they had a 3-year interval rather than a 1-year interval. CONCLUSIONS: A significant benefit in cancer stage at diagnosis was observed in all interval groups compared to never-screened. Endoscopy intervals of 3 years or less showed similar benefits, but family members of gastric cancer patients may benefit from intervals of under 3 years.

Association of colorectal adenoma with components of metabolic syndrome.

PURPOSE: Recently, some studies have shown that diabetes mellitus and metabolic syndrome increase the risk of colorectal neoplasms. Although the mechanism is not known, those have been proposed to contribute to this phenomenon, including insulin resistance, oxidative stress, and adipokine production. The objective of this study was to assess the association between metabolic risk factors and colorectal neoplasm. METHODS: Study participants visited the National Cancer Center, Korea, for screening (2007-2009). A total of 1,771 diagnosed adenoma patients and 4,667 polyp-free controls were included. The association between risk factors and colorectal neoplasm was evaluated using logistic regression models. RESULTS: High waist circumference, blood pressure, and serum triglyceride levels were associated with an increased risk of colorectal adenoma. Metabolic syndrome (MS) was associated with an increased risk of adenoma (OR = 1.44, 95 % CI = 1.23-1.70). The association between MS and colorectal adenoma was observed regardless of advanced/low-risk adenoma, and multiplicity. MS affected right colon adenomas (OR = 1.50, 95 % CI = 1.22-1.85), left colon adenomas (OR = 1.36, 95 % CI = 1.05-1.76), and adenomas in multiple anatomical locations (OR = 1.59, 95 % CI = 1.19-2.12), but was not associated with rectum. CONCLUSION: Central obesity, triglyceride level, and MS are risk factors for colorectal adenoma including advanced adenoma and multiplicity.

Small bowel cleanliness in capsule endoscopy: a case-control study using validated artificial intelligence algorithm.

Small bowel capsule endoscopy (SBCE) may need to be performed immediately after colonoscopy without additional bowel preparation if active small bowel diseases are suspected. However, it is unclear whether the small bowel cleanliness is adequately maintained even after SBCE is performed immediately after colonoscopy. We compared the small bowel cleanliness scores of the study group (SBCE immediately after colonoscopy) and control group (SBCE alone) using a validated artificial intelligence (AI) algorithm (cut-off score > 3.25 for adequate). Cases of SBCE in which polyethylene glycol was used were included retrospectively. Among 85 enrolled cases, 50 cases (58.8%) were the study group. The mean time from the last dose of purgative administration to SBCE was 6.86 ± 0.94 h in the study group and 3.00 ± 0.18 h in the control group. Seventy-five cases (88.2%) were adequate small bowel cleanliness, which was not different between the two groups. The mean small bowel cleanliness score for the study group was 3.970 ± 0.603, and for the control group was 3.937 ± 0.428. In the study group, better colon preparation resulted in a higher small bowel cleanliness score (p = 0.015). Small bowel cleanliness was also adequately maintained in SBCE immediately after colonoscopy. There was no difference between the time and volume of purgative administration and small bowel cleanliness.