1. National Engineering Research Center for Biomaterials, Sichuan University, Chengdu 610064, China
2. Sichuan Key Laboratory of Medical Imaging and School of Medical Imaging, North Sichuan Medical College, Fujiang Road 234, Nanchong, Sichuan 637000, China
3. Department of Radiology, West China Hospital, Sichuan University, Chengdu 610041, China