1. Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama;
2. Department of Neuro-Intervention, Osaka City General Hospital, Osaka;
3. Department of Radiology, Oita University Faculty of Medicine, Oita;
4. Department of Neuroendovascular Therapy, Kohnan Hospital, Sendai;
5. Department of Neurosurgery, Tokyo Metropolitan Neurological Hospital;
6. Department of Neuroendovascular Therapy, St. Luke’s International Hospital; and
7. Department of Endovascular Neurosurgery, Toranomon Hospital, Tokyo, Japan