1. Department of Gastroenterology and Hepatology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama 700‑8558, Japan
2. Division of Endoscopy, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama 700‑8558, Japan
3. Department of Gastroenterology and Hepatology, Hiroshima City Hiroshima Citizens Hospital, Hiroshima 730‑8518, Japan
4. Department of Gastroenterology and Hepatology, Kagawa Prefectural Central Hospital, Kagawa 760‑8557, Japan
5. Department of Diagnostic Pathology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama 700‑8558, Japan
6. Department of General Medicine, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama 700‑8558, Japan