1. Department of Neurosurgery, Hitachi General Hospital
2. Department of Neurosurgery, Tsukuba Medical Center Foundation
3. Department of Neurosurgery & Stroke, Institute of Clinical Medicine, University of Tsukuba
4. Department of Neurosurgery, Dokkyo Medical University Saitama Medical Center
5. Division of Stroke Prevention and Treatment, Faculty of Medicine, University of Tsukuba
6. Department of Endovascular Neurosurgery, Toranomon Hospital
7. Department of Neurosurgery, Mito Medical Center