1. Chinese PLA General Hospital, 104607, Gastroenterology of the second medical center, Beijing, Beijing, China, ;
2. Chinese PLA General Hospital, 104607, Beijing, Beijing, China, ;
3. Chinese PLA General Hospital, 104607, Gastroenterology of the Sceond medical center, 28 Fuxing Road, Haidian District, Beijing, Beijing, China, 100853, ;