[1] Juntendo Univ, Sch Med, Dept Radiol, Bunkyo Ku, 2-1-1 Hongo, Tokyo 1138421, Japan
[2] Univ Tokyo, Grad Sch Med, Dept Radiol, Tokyo, Japan
[3] Tokyo Metropolitan Univ, Grad Sch Human Hlth Sci, Dept Radiol Sci, Tokyo, Japan
[4] Juntendo Univ, Sch Med, Dept Neurosurg, Tokyo, Japan