1. Department of Health Informatics; Kyoto University School of Public Health; Kyoto
2. Unruptured Cerebral Aneurysm Study Japan Coordinating Office; University of Tokyo; Tokyo
3. Department of Neurological Surgery; Nippon Medical School; Tokyo
4. Division of Endovascular Neurosurgery, Department of Neurosurgery; Jikei University School of Medicine; Tokyo
5. Department of Neurosurgery, National Hospital Organization; Mito Medical Center; Ibaraki
6. Department of Neurosurgery, National Hospital Organization; Nagasaki Medical Center; Nagasaki
7. Department of Neurosurgery; University of Tokyo; Tokyo
8. Department of Neurosurgery; Kyorin University School of Medicine; Tokyo
9. Department of Neurological Surgery; Okayama University Graduate School of Medicine; Okayama
10. Department of Neurosurgery; Tohoku University Graduate School of Medicine; Sendai
11. Department of Neurosurgery; Shiga University of Medical Science; Otsu
12. Department of Neurosurgery; Hokkaido University Graduate School of Medicine; Sapporo
13. Department of Neurosurgery; Kyoto University Graduate School of Medicine; Kyoto
14. National Hospital Organization; Tokyo
15. Shinsapporo Neurosurgical Hospital; Sapporo Japan