[1] Univ Pittsburgh, Med Ctr, UPMC Stroke Inst, Pittsburgh, PA 15213 USA
[2] Swedish Med Ctr, Swedish Neurosci Inst, Seattle, WA USA
[3] St Louis Univ, Souers Stroke Inst, St Louis, MO 63103 USA
[4] St Louis Univ, Ctr Cerebrovasc Dis & Skull Base Surg, St Louis, MO 63103 USA
[5] Univ Pittsburgh, Med Ctr, Dept Neurosurg, Pittsburgh, PA 15213 USA