1Department of Radiology, The Second Xiangya Hospital, Central South University, No. 139 Middle Renmin Rd, Changsha, Hunan Province, 410011, P.R. China
2Changsha Public Health Treatment Center, Changsha, China
3Department of Radiology, First Hospital of Changsha, China
4Department of Radiology, The First People's Hospital of Changde City, Changde, China
5Department of Radiology, The Second People's Hospital of Changde City, Changde, China
6Department of Radiology Quality Control Center, Changsha, China