1. Department of Radiology, University of Washington, Seattle, WA.
2. Merck Research Laboratories, Rahway, NJ.
3. Department of Radiology, Massachusetts General Hospital, Boston, MA.
4. Department of Radiology, University of Pennsylvania, Philadelphia, PA.
5. Department of Radiology, University of Alabama, Birmingham, AL.
6. Department of Radiology, Beth Israel Deaconess Medical Center, Boston, MA.
7. Brown University Center for Statistical Sciences, Providence, RI.
8. Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, NY.
9. Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX.
10. Department of Radiology, Johns Hopkins Medical Center, Baltimore, MD.
11. Department of Radiology, University of Chicago, Chicago, IL.
12. Department of Radiology, University of California, 1600 Divisadero St, C255, Box 1667, San Francisco, CA 94115.