1. From the Department of Diagnostic Radiology, Creighton University School of Medicine, 3100 N Central Ave, Phoenix, AZ 85012 (D.C.); Department of Neuroradiology, Barrow Neurological Institute, Phoenix, Ariz (J.H., N.M., R.M.); and College of Liberal Arts and Sciences, Arizona State University, Tempe, Ariz (M.A.).