1. From the Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Tex (H.K.); Imaging Associates, National Heart Institute, New Delhi, India (V.G.); Department of Radiology, Thomas Jefferson University Hospital, 132 S 10th St, Philadelphia, PA 19107 (A.G., M.P.); and Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia, Pa (A.D.).