Xuecan Mei1, Xi Wang1, Wenyue Wu1, Yi Xiang1, Yi Han2, Derun Kong1,2. 1. Department of Gastroenterology, the First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China. 2. Department of Gastroenterology, Fuyang Hospital of Anhui Medical University, Fuyang, Anhui, China.