1 From the Department of Diagnostic Radiology, Yale University School of Medicine, 789 Howard Ave, TE2-230, New Haven, CT 06519-1304 (J.A.B.); and Department of Diagnostic Radiology, Mayo Clinic, Jacksonville, Fla (R.L.M.). Received August 26, 2012; revision requested August 28; revision received and final version accepted August 30. Address correspondence to J.A.B. (e-mail: [email protected]).