1. Department of Gastroenterology; Yokote Municipal Hospital; 5-31 Negishi-cho, Yokote-shi, Akita 013-8602 Japan
2. Department of Gastroenterology; Akita Red Cross Hospital; 222-1 Kamikitade Saruta, Akita-shi, Akita 010-1495 Japan
3. Department of Surgery; Akita Red Cross Hospital; 222-1 Kamikitade Saruta, Akita-shi, Akita 010-1495 Japan
4. Department of Pathology; Akita Red Cross Hospital; 222-1 Kamikitade Saruta, Akita-shiAkita 010-1495 Japan
5. Department of Radiology; Akita Red Cross Hospital; 222-1 Kamikitade Saruta, Akita-shi, Akita 010-1495 Japan