1. From the Department of Neuroradiology, American Institute for Radiologic Pathology, 1011 Wayne Ave, Suite 320, Silver Spring, MD 20910 (K.K.K., R.Y.S.); Department of Radiology, Mayo Clinic, Rochester, Minn (K.K.K.); Uniformed Services University of the Health Sciences, Bethesda, Md (R.Y.S.); and Department of Radiology, Walter Reed National Military Medical Center, Bethesda, Md (R.Y.S.).