1. Department of Radiology, The Hainan Branch of The Chinese PLA General Hospital, Sanya, Hainan 572013, P.R. China
2. Department of Radiology, The First Affiliated Hospital, Northern Hebei College, Zhangjiakou, Hebei 075000, P.R. China
3. Department of Radiology, The General Hospital, Tianjin Medical University, Tianjin, Hebei 300052, P.R. China