[1] Keio Univ, Sch Med, Dept Cardiol, Tsukuba, Ibaraki, Japan
[2] Keio Univ, Sch Med, Dept Diagnost Radiol, Tsukuba, Ibaraki, Japan
[3] Keio Univ, Sch Med, Dept Cardiovasc Surg, Tsukuba, Ibaraki, Japan
[4] Tsukuba Med Ctr Hosp, Dept Cardiol, Tsukuba, Ibaraki, Japan