1. Department of Gastroenterology, Graduate School of Medicine; The University of Tokyo; Tokyo Japan
2. Department of Hepatology; National Center for Global Health and Medicine; Tokyo Japan
3. Department of Gastroenterology; JR Tokyo General Hospital; Tokyo Japan
4. Department of Gastroenterology; Japanese Red Cross Medical Center; Tokyo Japan
5. Department of Gastroenterology; Tokyo Metropolitan Police Hospital; Tokyo Japan
6. Endoscopy and Endoscopic Surgery; The University of Tokyo Hospital; Tokyo Japan
7. Ohta Nishinouchi Hospital; Fukushima Japan