1. Department of Neurosurgery, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266000, P.R. China
2. Department of Neurosurgery, The Affiliated Hospital of Weifang Medical University, Weifang, Shandong 261031, P.R. China
3. Department of Radiology, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266000, P.R. China