[1] Northwestern Univ, Feinberg Sch Med, Dept Radiol, Chicago, IL USA
[2] Lurie Childrens Hosp, Dept Radiol, Chicago, IL USA
[3] Ain Shams Univ, Fac Med, Dept Radiol, Cairo, Egypt
[4] Northwestern Univ, Dept Neurol Surg, Feinberg Sch Med, Evanston, IL USA
[5] Northwestern Univ, Feinberg Sch Med, Dept Neurol Surg, Chicago, IL USA
[6] Northwestern Univ, Feinberg Sch Med, 676 N St Clair St,Suite 800, Chicago, IL 60611 USA