1. Department of Pancreatic Surgery, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, P.R. China
2. Department of Radiology, The First People's Hospital of Chengdu, Chengdu, Sichuan 610095, P.R. China
3. Kunming University School of Medicine, Kunming University School, Kunming, Yunnan 650124, P.R. China