[1] Johns Hopkins Univ, Sch Med, Russell H Morgan Dept Radiol & Radiol Sci, Div Intervent Neuroradiol, Baltimore, MD USA
[2] Johns Hopkins Univ, Sch Med, Div Pediat Radiol, Sect Pediat Neuroradiol,Russell H Morgan Dept Rad, Baltimore, MD USA
[3] Johns Hopkins Univ, Dept Neurol, Div Neuroimmunol, Baltimore, MD 21218 USA
[4] Univ Zurich, Dept Neuropediat, Zurich, Switzerland
[5] Russell H Morgan Dept Radiol & Radiol Sci, Sect Pediat Neuroradiol, Div Neuroradiol, Baltimore, MD 21287 USA