1. Department of Neurological Surgery, Chiba Hokuso Hospital, Nippon Medical School
2. Department of Neurosurgery, Kushiro Rosai Hospital
3. Department of Radiology, Chiba Shintoshi Rurban Clinic
4. Department of Neurological Surgery, Nippon Medical School
5. Department of Neurosurgery, Chiba Shintoshi Rurban Clinic