1. From the Department of Radiology, Stanford University School of Medicine, 300 Pasteur Dr, Stanford, CA 94305-5105 (D.B.L.); Texas Children’s Hospital, Houston, Tex (L.F.D.); Nemours Children’s Health System, Orlando, Fla (D.J.P.); Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio (A.C.M.); Kaiser Permanente, Denver, Colo (R.E.S.); and Beth Israel Deaconess Medical Center, Boston, Mass (J.B.K.).