[1] Stanford Univ, Sch Med, Dept Radiol, Stanford, CA 94305 USA
[2] Stanford Univ, Sch Med, MIPS, Stanford, CA 94305 USA
[3] Peking Union Med Coll, Tianjin, Peoples R China
[4] Chinese Acad Med Sci, Inst Hematol, State Key Lab Expt Hematol, Tianjin, Peoples R China
[5] Stanford Univ, Sch Med, Dept Med, Div Cardiol, Stanford, CA 94305 USA