[1] Massachusetts Gen Hosp, Dept Radiol, Ctr Neurosci, Stroke & Neurovasc Regulat Lab, Charlestown, MA 02129 USA
[2] Harvard Univ, Sch Med, Massachusetts Gen Hosp, Dept Radiol,Neuroprotect Res Lab, Charlestown, MA 02129 USA
[3] Harvard Univ, Sch Med, Massachusetts Gen Hosp, Dept Neurol, Charlestown, MA 02129 USA
[4] Hacettepe Univ, Fac Med, Dept Neurol, TR-06100 Ankara, Turkey