[1] Kyushu Univ, Grad Sch Med Sci, Dept Clin Radiol, Higashi Ku, 3-1-1 Maidashi, Fukuoka, Fukuoka 8128582, Japan
[2] Kyushu Univ, Grad Sch Med Sci, Dept Neurosurg, Higashi Ku, 3-1-1 Maidashi, Fukuoka, Fukuoka 8128582, Japan
[3] Kyushu Univ, Grad Sch Med Sci, Dept Neuropathol, Higashi Ku, 3-1-1 Maidashi, Fukuoka, Fukuoka 8128582, Japan
[4] Philips Elect Japan, MR Clin Sci, Minato Ku, 13-37 Kohnan,2 Chome, Tokyo 1088507, Japan