1. Department of Epidemiology and Biostatistics, University of California, San Francisco
2. Department of Radiology, University of California, San Francisco
3. Department of Radiology, University of California, San Diego
4. Department of Public Health Sciences, UC Davis, and Kaiser Permanente Washington Health Research Institute, Kaiser Foundation Health Plan of Washington
5. Department of Radiology, University of California, Irvine
6. Department of Radiology, University of California, Los Angeles