A Comparison of pCLE Based Targeted Biopsy and WLE Based Standard Biopsy in Staging the Operative Link on Gastric Intestinal Metaplasia (OLGIM): A Randomized，Cross-over Study

Inclusion Criteria: * Patients aged 40 years or older with Helicobacter pylori infection; * Histologically verified GIM, atrophic gastritis or dysplasia. Exclusion Criteria: * Patients with gastrectomy, acute GI bleeding and advanced gastric cancer; * Conditions unsuitable for performance of pCLE, such as coagulopathy, impaired renal function or allergy to fluorescein sodium; * Pregnancy or breastfeeding; * Inability to provide informed consent and other situations that could interfere with the examination or therapeutic protocol.