1. From Johns Hopkins University, School of Medicine, Departments of Radiology (D.L.K., E.A., J.W.M.B.) and Medicine, Division of Cardiology (A.W.H., L.C.A., J.M.H.), Baltimore, Md; Osiris Therapeutics, Inc (B.J.M., M.F.P.), Baltimore, Md; and Department of Electrical and Electronics Engineering, Bilkent University, Ankara, Turkey (E.A.).