[1] Univ Penn, Childrens Hosp Philadelphia, Dept Pediat, Div Pediat Emergency Med,Perelman Sch Med, Philadelphia, PA 19104 USA
[2] Steven & Alexandra Cohen Childrens Med Ctr New Yo, Pediat Emergency Dept, New Hyde Pk, NY USA
[3] Univ Penn, Childrens Hosp Philadelphia, Perelman Sch Med, Dept Pediat,Div Dev & Behav Pediat, Philadelphia, PA 19104 USA
[4] Univ Penn, Childrens Hosp Philadelphia, Perelman Sch Med, Dept Radiol,Div Neuroradiol, Philadelphia, PA 19104 USA
[5] Univ Penn, Childrens Hosp Philadelphia, Perelman Sch Med, Dept Pediat,Div Gen Pediat, Philadelphia, PA 19104 USA
[6] Western Michigan Univ, Homer Stryker MD Sch Med, Kalamazoo, MI 49008 USA