1. Department of Radiology, the Second Affiliated Hospital, Medical College of Shantou University, Shantou 515041, P.R. China
2. Department of Pathology, Medical College of Shantou University, Guangdong, Shantou 515031, P.R. China
3. Division of Neuroradiology, Department of Medical Imaging, University Health Network, Toronto, Ontario M5T 2S7, Canada
4. Department of Radiology, the First Affiliated Hospital of Guangzhou Medical University, Guangzhou 510120, P. R. China
5. Department of Radiology, the Second Affiliated Hospital of Xiamen Medical College, Xiamen, Fujian Province 361022, China
6. Provincial Key Laboratory of Medical Molecular Imaging, Guangdong, Shantou 515041, P.R. China