1. From the Departments of Radiology (A.C., C.L.V., P.N., N.A.H., V.Y., F.H.M.) and Pathology (A.J.B., G.Y.Y.), Northwestern Memorial Hospital, Northwestern University Feinberg School of Medicine, 676 N St. Clair St, Suite 800, Chicago, IL 60611; Department of Radiology, Emory University School of Medicine, Atlanta, Ga (P.K.M.); and Department of Radiology, Mayo Clinic, Scottsdale, Ariz (C.O.M.).