[1] Drexel Univ, Coll Med, Dept Pediat, St Christophers Hosp Children, Philadelphia, PA 19104 USA
[2] Drexel Univ, Dept Radiol, Coll Med, St Christophers Hosp Children, Philadelphia, PA 19104 USA
[3] Drexel Univ, Dept Surg, Coll Med, St Christophers Hosp Children, Philadelphia, PA 19104 USA
[4] Temple Univ, St Christophers Hosp Children, Sch Med, Dept Pediat, Philadelphia, PA 19122 USA