1. From the Department of Radiology, Stanford University School of Medicine, 725 Welch Rd, Palo Alto, CA 94304 (E.J.Z., Y.C., L.C., R.B.D., T.H.R., D.P.F., D.B.L.); and Sedation Program (S.W.), Department of Anesthesia (T.N.W.), and Department of Performance Improvement (L.L.), Stanford Children's Health, Stanford, Calif.