1. From the Department of Radiology and Bio-X Program (F.C., S.L., X.X., P.R., M.P., X.Z., X.C., S.S.G., J.C.W.), the Department of Pathology and Developmental Biology (M.D., S.J.D., A.J.C., I.L.W.), the Department of Bioengineering (S.S.G.), and the Department of Medicine, Division of Cardiology (J.C.W.), Stanford University School of Medicine, Stanford, Calif.