1. Department of Radiology, Beijing Friendship Hospital, Capital Medical University, Beijing 100050, China
2. Neuroradiology Division, Department of Radiology, Stanford University, Stanford, CA 94305, USA
3. Department of Radiology, Beijing Tongren Hospital, Capital Medical University, Beijing 100730, China
4. Department of Otolaryngology Head and Neck Surgery, Beijing Friendship Hospital, Capital Medical University, Beijing 100050, China