1. From the Department of Radiology, Guangdong General Hospital/Guangdong Academy of Medical Sciences, Guangzhou, Guangdong, P.R. China
2. Department of Radiology, The First People's Hospital of Shunde, Foshan, Guangdong, P.R. China
3. Department of Radiology, Affiliated Hospital of Guizhou Medical University, Guizhou, P.R. China