3 Department of Diagnostic and Interventional Neuroradiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
4 Department of Neurosurgery and Radiology, University at Buffalo, Buffalo, NY, USA.
5 Department of Neurosurgery, University of Michigan, Ann Arbor, MI, USA.
6 Brain Center, Affiliated Zhejiang Hospital, Zhejiang University School of Medicine, No. 1229 Gudun Road, Hangzhou, 310030, Zhejiang, China. wanshu@zju.edu.cn.