1. Department of Anatomy, College of Basic Medicine, Dalian Medical University, Dalian, P. R. China
2. Department of Radiology, The 403 Affiliated Hospital of Chinese PLA General Hospital, Dalian, P. R. China
3. Department of Neurology, The Second Affiliated Hospital of Dalian Medical University, Dalian, P. R. China
4. Shangdong Medical Imaging Research Institute, School of Medicine, Shandong University, Jinan, P. R. China