[1] Univ Penn, Sch Med, Sch Med, Philadelphia, PA 19104 USA
[2] Univ Penn, Sch Med, Dept Radiol, Philadelphia, PA 19104 USA
[3] Univ Penn, Sch Med, Dept Med, Philadelphia, PA 19104 USA
[4] Univ Penn, Sch Med, Ctr Clin Epidemiol & Biostat, Philadelphia, PA 19104 USA
[5] Univ Penn, Sch Med, Leonard Davis Inst Hlth Econ, Philadelphia, PA 19104 USA
[6] Univ Michigan, Consortium Hlth Outcomes Innovat & Cost Effective, Ann Arbor, MI USA