1. From the Department of Radiology and Imaging Sciences, National Institutes of Health, Bethesda, Md (J.M.); American Institute for Radiologic Pathology, 1100 Wayne Ave, Suite 1020, Silver Spring, MD 20910 (J.M., D.J.W.); Department of Radiology, Johns Hopkins School of Medicine, Washington, DC (D.J.W., A.L.A.); and Joint Pathology Center, Silver Spring, Md (I.A.S.).