1. Department of NeurosurgeryKeio University School of Medicine Tokyo Japan
2. Department of NeurosurgeryJikei University Kashiwa Hospital Chiba Japan
3. Division of Diagnostic PathologyKeio University School of Medicine Tokyo Japan
4. Department of NeurosurgeryKagawa University Hospital Kagawa Japan
5. Department of NeurosurgeryEiju General Hospital Tokyo Japan
6. Department of NeurosurgeryJikei University Hospital Tokyo Japan