1. 1Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.
2. 2Department of Radiology, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.
3. 3Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, North Carolina.
4. 4Division of Gastroenterology and Hepatology, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.
5. 5Division of Oncology, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.
6. 6Department of Health Policy and Management, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.