1. Division of Neurology, Department of Medicine, Jichi Medical University School of Medicine, Shimotsuke, Japan
2. Division of Cardiovascular Medicine, Department of Medicine, Jichi Medical University School of Medicine, Shimotsuke, Japan
3. Center for Endovascular Therapy, Division of Neuroendovascular Surgery, Jichi Medical University School of Medicine, Shimotsuke, Japan
4. Department of Neurosurgery, Jichi Medical University School of Medicine, Shimotsuke, Japan