1. Department of Medical Imaging, People's Hospital of Tongchuan, Tongchuan, Shaanxi 727000, P.R. China
2. Department of Interventional Radiography, Tongchuan Mining Bureau Central Hospital, Tongchuan, Shaanxi 727000, P.R. China
3. Department of Interventional Radiography, Ninth Hospital of Xi'an, Xi'an, Shaanxi 710054, P.R. China