1. Department of Gastroenterology, Xinghua Renming Hospital, Jiangsu, P.R. China
2. Department of Gastroenterology and Hepatology, Zhongshan Hospital, Fudan University, Shanghai, P.R.China
3. Department of Gastroenterology and Hepatology, Minhang Hospital, Fudan University, Shanghai, P.R. China
4. Endoscopy Center and Endoscopy Research Institute, Zhongshan Hospital, Fudan University, Shanghai, P.R. China
5. Department of Gastroenterology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, P.R. China