Currently, the Correa cascade is a widely accepted model of gastric carcinogenesis. Intestinal metaplasia is a high risk factor for gastric cancer. According to Sydney criteria, mild intestinal metaplasia was not associated with gastric cancer, while moderate to severe intestinal metaplasia was strongly associated with the development of gastric cancer. Because intestinal metaplasia is distributed in various forms, the use of white light endoscopy lacks specificity, and the consistency with histopathological diagnosis is poor; Pathological biopsy is still needed to make a diagnosis. At present, national guidelines suggest that OLGIM score should be used to evaluate the risk of gastric cancer, and patients with OLGIM grade III/IV should be monitored by close gastroscopy. However, it requires at least four biopsies, which is clinically infeasible. Confocal laser endomicroscopy allows real-time observation of living tissue, comparable to pathological findings.

Gastric cancer is a common malignant tumor in digestive system diseases. Currently, the Correa cascade is a widely accepted model of gastric carcinogenesis. Intestinal metaplasia is a high risk factor for gastric cancer and is considered a precancerous condition of intestinal type gastric cancer. According to Sydney criteria, mild intestinal metaplasia was not associated with gastric cancer, while moderate to severe intestinal metaplasia was strongly associated with the development of gastric cancer. Because intestinal metaplasia is distributed in various forms, the use of white light endoscopy lacks specificity, and the consistency with histopathological diagnosis is poor; Pathological biopsy is still needed to make a diagnosis. At present, our national guidelines suggest that OLGIM score should be used to evaluate the risk of gastric cancer, and patients with OLGIM grade III/IV should be monitored by close gastroscopy. However, it requires at least four biopsies, which is clinically infeasible. Confocal laser endomicroscopy allows real-time observation of living tissue, comparable to pathological findings. Therefore, we established artificial intelligence-assisted confocal laser endoscope technology to determine the high risk of gastric cancer in real time, instead of tissue biopsy.

Inclusion Criteria:

• Patients aged 18-80 years undergoing confocal gastroscopy

Exclusion Criteria:

• Patients with severe cardiac, cerebral, pulmonary or renal dysfunction or psychiatric disorders who cannot participate in gastroscopy
• Patients with previous surgical procedures on the stomach
• Patients with contraindications to biopsy
• Patients who refuse to sign the informed consent form

Consecutive patients who receive the upper gastrointestinal tract pCLE examination and screened that fulfill the eligibility criteria at Qilu Hospital, Shandong University will be enrolled into the study.