1. Department of Endovascular Surgery, Tokyo Medical and Dental University, Tokyo, Japan
2. Department of Neurosurgery, Tokyo Medical and Dental University, Tokyo, Japan
3. Department of Neurosurgery, Jichi Medical University Saitama Medical Center, Saitama, Saitama, Japan
4. Department of Ophthalmology & Visual Science, Tokyo Medical and Dental University, Tokyo, Japan