[1] Tohoku Univ, Sch Hlth Sci, Fac Med, Dept Radiol Technol,Aoba Ku, Sendai, Miyagi 9808575, Japan
[2] Akita Med Ctr, Dept Radiol, Akita 0100874, Japan
[3] Tohoku Univ, Grad Sch Med, Dept Cardiovasc Med, Aoba Ku, Sendai, Miyagi 9808574, Japan
[4] Tohoku Univ, Grad Sch Med, Dept Radiol, Aoba Ku, Sendai, Miyagi 9808574, Japan