Zhen-Zhen Zhai1, Le Wang2, Xiu-Li Zuo3. 1. Department of Gastroenterology, Qilu Hospital of Shandong University, Jinan, Shandong Province, China; Department of Gastroenterology, Dezhou People's Hospital, Dezhou, Shandong Province, China. 2. Department of Gastroenterology, Dezhou People's Hospital, Dezhou, Shandong Province, China. 3. Department of Gastroenterology, Qilu Hospital of Shandong University, Jinan, Shandong Province, China.