1. Department of Gastroenterology and Hepatology; Tokyo Medical University; 6-7-1 Nishishinjuku, Shinjuku-ku Tokyo 160-0023 Japan
2. Third Department of Surgery; Tokyo Medical University; Tokyo Japan
3. Third Department of Surgery, Hachioji Medical Center; Tokyo Medical University; Tokyo Japan
4. Fifth Department of Surgery, Hachioji Medical Center; Tokyo Medical University; Tokyo Japan
5. Department of Radiology, Yokohama Seibu Hospital; St. Marianna University; Yokohama Japan