1. Department of Medicine; University of California; San Francisco CA USA
2. Department of Epidemiology and Biostatistics; University of California; San Francisco CA USA
3. Medical Service; San Francisco Veterans Affairs Health Care System; San Francisco CA USA
4. Department of Radiology and Biomedical Imaging; University of California; San Francisco CA USA
5. Department of Surgery; University of California; San Francisco CA USA
6. Surgical Service; San Francisco Veterans Affairs Health Care System; San Francisco CA USA