[1] Prefectural Univ Hiroshima, Grad Sch Comprehens Sci Res, Biol Syst Sci Program, 1-1 Gakuen Cho, Mihara, Hiroshima 7230053, Japan
[2] Shimane Univ Hosp, Dept Radiol, 89-1 Enya Cho, Izumo, Shimane 6938501, Japan
[3] Kawasaki Med Sch, Dept Radiol, Gen Med Ctr, Kita Ku, 2-6-1 Nakayamashita, Okayama 7008505, Japan
[4] Shimane Univ, Dept Radiol, Fac Med, 89-1 Enya Cho, Izumo, Shimane 6938501, Japan
[5] Shimane Univ, Dept Neurol, Fac Med, 89-1 Enya Cho, Izumo, Shimane 6938501, Japan