Xiaotian Sun1, Yan Liu2, Min Min2, Yiliang Bi2, Yang Xu2. 1. Department of Gastroenterology, The 307 Hospital of Academy of Military Medical Science, Beijing 100171; Department of Internal Medicine, Clinic of August First Film Studio, Beijing 100161, China. 2. Department of Gastroenterology, The 307 Hospital of Academy of Military Medical Science, Beijing 100171, China.