[1] Vanderbilt Univ, Sch Med, Nashville, TN 37232 USA
[2] Vanderbilt Univ, Med Ctr, Div Pediat Neurol, Dept Pediat, Nashville, TN 37232 USA
[3] Vanderbilt Univ, Med Ctr, Div Pediat Emergency Med, Dept Pediat, Nashville, TN 37232 USA
[4] Washington Univ, Sch Med, Dept Neurol, Div Pediat Neurol, St Louis, MO 63110 USA
[5] Northwestern Univ, Dept Pediat, Feinberg Sch Med, Div Crit Care Med, Chicago, IL 60611 USA
[6] Vanderbilt Univ, Med Ctr, Dept Radiol & Radiol Sci, Div Pediat Radiol, Nashville, TN 37232 USA
[7] Arkansas Childrens Hosp, Dept Pediat, Div Pediat Emergency Med, Little Rock, AR 72202 USA