1. From the Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 S Kingshighway Blvd, Campus Box 8131, St Louis, MO 63110 (L.J.S., D.A.R., S.B.); Department of Diagnostic Radiology and Nuclear Medicine, Rush University Medical Center, Chicago, Ill (K.P.); Department of Cardiology, St Louis Children’s Hospital, St Louis, Mo (T.A.R.); and Department of Radiology, Mercy Hospital, St Louis, Mo (E.F.S.).