[1] Univ Tokyo, Grad Sch Med, Tokyo, Japan
[2] Univ Tokyo, Grad Sch Med, Hepatobiliary Pancreat Surg Div, Tokyo, Japan
[3] Univ Tokyo, Dept Biostat, Sch Publ Hlth, Tokyo, Japan
[4] Nihon Univ, Dept Digest Surg, Sch Med, Tokyo, Japan
[5] Musashino Red Cross Hosp, Dept Gastroenterol & Hepatol, Tokyo, Japan
[6] Shinshu Univ, Dept Radiol, Sch Med, Matsumoto, Nagano, Japan
[7] Kinki Univ, Sch Med, Osaka, Japan
[8] Kobe Univ, Div Hepatobiliary Pancreat Surg, Grad Sch Med, Kobe, Hyogo, Japan
[9] Keio Univ, Dept Pathol, Sch Med, Tokyo, Japan
[10] Kurume Univ Hosp, Dept Clin Inspect, Kurume, Fukuoka, Japan
[11] Kanazawa Univ Hosp, Dept Gastroenterol, Kanazawa, Ishikawa, Japan