T Inaba1, M Iwamuro2,3, T Toyokawa4, H Okada5,6. 1. Department of Gastroenterology, Kagawa Prefectural Central Hospital, Takamatsu, Japan. 2. Department of Gastroenterology and Hepatology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan. iwamuromasaya@yahoo.co.jp. 3. Department of General Medicine, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan. iwamuromasaya@yahoo.co.jp. 4. Department of Gastroenterology, Fukuyama Medical Center, Fukuyama, Japan. 5. Department of Gastroenterology and Hepatology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan. 6. Department of Endoscopy, Okayama University Hospital, Okayama, Japan.