[1] Univ Penn, Med Ctr, Pulm Allergy & Crit Care Div, Sch Med,Web Applicat Grp, Philadelphia, PA 19104 USA
[2] Univ Penn, Sch Med, Dept Med, Ctr Clin Epidemiol & Biostat, Philadelphia, PA 19104 USA
[3] Univ Penn, Sch Med, Div Infect Dis, Dept Med, Philadelphia, PA 19104 USA
[4] Univ Penn, Sch Med, Dept Radiol, Philadelphia, PA 19104 USA
[5] Univ Penn, Sch Med, Med Informat Grp, Dept Informat Serv, Philadelphia, PA 19104 USA