1 Department of Endovascular Neurosurgery, Saitama Medical University International Medical Center, 1397-1 Yamane, Hidaka City, Saitama, 350-1298, Japan. yukihiro.imaoka@gmail.com.
2 Department of Neurosurgery, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Kumamoto City, Kumamoto, 860-8556, Japan. yukihiro.imaoka@gmail.com.
3 Department of Endovascular Neurosurgery, Saitama Medical University International Medical Center, 1397-1 Yamane, Hidaka City, Saitama, 350-1298, Japan.
4 Department of Stroke and Cerebrovascular Medicine, Kyorin University, 6-20-2 Shinkawa, Tokyo, Mitaka, 181-8611, Japan.