1. Department of Neurosurgery, Neurological Institute, and
2. Department of Surgery, Hsinchu Branch, Taipei Veterans General Hospital, Hsinchu, Taiwan, Republic of China; and
3. School of Medicine, National Yang-Ming University, Taipei;
4. Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia
5. Department of Radiology, Taipei Veterans General Hospital;