[1] Univ Tennessee, Hlth Sci Ctr, Dept Radiol, Memphis, TN 38103 USA
[2] Univ Tennessee, Hlth Sci Ctr, Dept Neurosurg, Memphis, TN 38103 USA
[3] Univ Tennessee, Hlth Sci Ctr, Dept Ophthalmol, Memphis, TN 38103 USA
[4] Le Bonheur Childrens Hosp, Le Bonheur Neurosci Inst, Memphis, TN 38103 USA
[5] Johns Hopkins Univ, Dept Radiol & Radiol Sci, Div Neuroradiol, Baltimore, MD 21287 USA
[6] Univ Maryland, Dept Radiol, Div Neuroradiol, Baltimore, MD 21201 USA
[7] Univ Maryland, Dept Neurol, Baltimore, MD 21201 USA
[8] Univ Maryland, Dept Neurosurg, Baltimore, MD 21201 USA