1. Division of Stroke Prevention and Treatment, Faculty of Medicine, University of Tsukuba
2. Department of Neurosurgery, Faculty of Medicine, University of Tsukuba
3. Department of Stroke Neurology, National Hospital Organization Osaka National Hospital
4. Department of Neurosurgery, National Cerebral and Cardiovascular Center
5. Department of Neurosurgery, Graduate School of Medical Sciences Kyusyu University
6. Department of Neurosurgery, Kobe City Medical Center General Hospital