1. Department of Radiology, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia (J.A.C., G.O., R.M., S.G., S.R.A.).
2. Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia (J.A.C., B.A., V.S., D.K., I.E., G.O., R.M., J.L., A.S.).
3. Hospital of the University of Pennsylvania, Philadelphia (J.A.C., G.O., R.M., S.G.).
4. Department of Medicine, University of Massachusetts Medical School, Worcester (M.S.).