1. Department of Surgery, Division of Gastroenterological and Hepatobiliary Surgery, and Organ Transplantation, University of Tsukuba, Tsukuba, Japan
2. Mito Chuo Hospital, Mito, Japan
3. Department of Mechano-Informatics, Graduate School of Information Science and Technology, University of Tokyo, Tokyo, Japan
4. Department of Pathology, Faculty of Medicine, Diagnostic Pathology, University of Tsukuba Hospital, Tsukuba, Japan