[1] Univ N Carolina, Cecil G Sheps Ctr Hlth Serv Res, Sch Med, Chapel Hill, NC 27515 USA
[2] Univ N Carolina, Lineberger Comprehens Canc Ctr, Sch Med, Chapel Hill, NC 27515 USA
[3] Univ N Carolina, Sch Med, Dept Radiol, Chapel Hill, NC 27515 USA
[4] Univ Texas Austin, Dell Med Sch, Dept Med, Austin, TX 78712 USA
[5] Univ N Carolina, Sch Med, Div Gen Internal Med & Clin Epidemiol, Dept Med, Chapel Hill, NC 27515 USA
[6] UNC Hlth Care, Inst Healthcare Qual & Improvement, Chapel Hill, NC USA
[7] Univ North Carolina Chapel Hill, Div Pulm Dis & Crit Care Med, Carrboro, NC 27510 USA
[8] Vanderbilt Univ, Vanderbilt Inst Clin & Translat Res, 221 Kirkland Hall, Nashville, TN 37235 USA