1 1 Department of Radiology, University of Kentucky, Lexington, Kentucky.
2 2 Department of Radiology, University of Missouri-Kansas City, and Department of Radiology, Saint Luke's Hospital of Kansas City, Kansas City, Missouri.
3 3 Department of Diagnostic Radiology, University of Texas-M.D. Anderson Cancer Center, Houston, Texas; and.
4 4 Department of Radiology, University of Chicago, Chicago, Illinois.