1. Department of Gastroenterology, Jiaozhou Central Hospital of Qingdao, Shandong, China
2. Department of Gastroenterology, Yidu Central Hospital of Weifang, Shandong, China
3. Department of 3rd General Surgery, The Fourth Affiliated Hospital of China Medical University, Liaoning, China
4. Department of General Gastroenterology, Zhucheng People’s Hospital, Shandong, China