[1] Univ Pennslvania, Perelman Sch Med, Div Gen Pediat Clin Futures, Philadelphia, PA 19104 USA
[2] Univ Pennslvania, Perelman Sch Med, Childrens Hopsital Philadelphia, Dept Radiol, Philadelphia, PA 19104 USA
[3] Univ Pennslvania, Perelman Sch Med, Dept Pediat, Philadelphia, PA 19104 USA
[4] Univ Colorado, Kempe Ctr Prevent & Treatment Child Abuse & Neglec, Sch Med, Dept Emergency Med, 12631 E 17 th Ave Mailstop C326, Aurora, CO 80045 USA
[5] Univ Utah, Primary Childrens Hosp, Ctr Safe & Hlth Families, Dept Pediat, Salt Lake City, UT USA
[6] Univ Penn, Childrens Hosp Philadelphia, Perelman Sch Med, Div Gen Pediat,PolicyLab & Clin Futures, Philadelphia, PA 19104 USA