1. Department of Radiology, Affiliated Lishui Hospital of Zhejiang University, The Fifth Affiliated Hospital of Wenzhou Medical University, The Central Hospital of Zhejiang, Zhejiang 323000, P. R. China
2. Department of Hepatobiliary Surgery, Beijing Chao-Yang Hospital Affiliated with Capital Medical University, Beijing 100043, P. R. China
3. Department of Radiology, Zhong-da Hospital, Medical School, Southeast University, Nanjing 210009, P. R. China
4. Department of Radiology, Lab-Yang, University of Washington, Seattle, WA 98109, USA