Inclusion Criteria:

1.Provision of written informed consent; 2.Participants of the 'Gastric Pathologies Screening Programme for the Elderly and High Risk Groups in Guangzhou Municipality', the following are the criteria for inclusion in this public welfare programme:

1. Elderly cohort: Permanent residents of Guangzhou aged ≥60 years who have not undergone specialized gastric disease screening in the past three years;

2. Or high-risk cohort: Individuals aged ≥45 years who meet at least one of the following risk criteria:

   1. History of Helicobacter pylori infection (positive ¹³C/¹⁴C urea breath test);
   2. Prior diagnosis of chronic atrophic gastritis, gastric ulcer, neoplastic gastric polyps, hypertrophic gastritis, or pernicious anemia;
   3. Family history of gastric cancer (first-degree relative with a confirmed diagnosis);
   4. Long-term high-salt diet, smoking history (≥20 pack-years), or heavy alcohol consumption (100 mL of distilled spirits/day).

Exclusion Criteria:

1. Not considered by the investigator to be suitable for participation in this study.
2. Meets the exclusion criteria of the Public Welfare Programme. Individuals will be excluded if they meet any of the following conditions:

(1)Known allergy to medical polymer materials; (2)Psychiatric disorders that interfere with procedural cooperation; (3)Pregnancy or lactation; (4)Severe systemic comorbidities (e.g., cardiovascular, respiratory, neurological diseases) affecting examination tolerance; (5)Inflammatory bowel disease (Crohn's disease or ulcerative colitis) or gastrointestinal diverticulosis; (6)Known or suspected gastrointestinal malformations, obstructions, strictures, or fistulas; (7)Clinically significant dysphagia; (8)Acute abdominal symptoms (e.g., pain, vomiting, suspected bowel obstruction, or severe constipation); (9)History of major gastrointestinal surgery (e.g., esophagogastrostomy, gastrojejunostomy); (10)Physical debilitation precludes postural changes or concurrent severe illness; (11)Medically ineligible for abdominal procedures or refusal to undergo them; (12)Deemed unsuitable for MCG by the investigator; (13)Refusal to provide informed consent; (14)Any other condition judged by the investigator to make the individual unsuitable for study participation.