1. From the Department of Radiology and Imaging Sciences (G.J., K.A.C., T.N.H., K.D.H.) and Department of Emergency Medicine (G.J., T.N.H., K.D.H.), Emory University School of Medicine, 550 Peachtree St, Atlanta, GA 30308; and Department of Radiology, Mayo Clinic, Scottsdale, Ariz (N.D., C.O.M.).