1. From the Cardiac MR PET CT Program, Department of Radiology (S.A.J., P.V.S., B.S., R.A.P.T., T.M., O.H., H.A.E., J.P., A.I., T.R.H., M.T.L., U.H., T.G.N.), Neuroradiology Division, Department of Radiology (J.M.R.), Program in Nutritional Metabolism (S.K.G., M.V.Z.), and Division of Cardiology, Department of Medicine (S.A.J., P.V.S., B.S., R.A.P.T., T.M., O.H., H.A.E., J.P., A.I., T.R.H., M.T.L., U.H., T.G.N.), Massachusetts General Hospital and Harvard Medical School, Boston.