1. From the Department of Neuroradiology, Walter Reed National Military Medical Center and Uniformed Services University of Health Sciences, 8901 Rockville Pike, Bethesda, MD 20889 (J.C., M.E.P., V.C.L., J.K.D.); Department of Neuroradiology, University of Utah, Salt Lake City, Utah (M.D.A., J.S.M.); and Department of Radiology, Weill Cornell Medicine, New York, NY (E.M.H.).