1. Department of Neurosurgery, MOJI Medical Center. Moji-ku, Kitakyushu 801-0853, Japan
2. Department of Radiology, MOJI Medical Center. Moji-ku, Kitakyushu 801-0853, Japan
3. Department of Neurosurgery, School of Medicine, University of Occupational and Environmental Health Japan. Yahatanishi-ku, Kitakyushu 807-8555, Japan