[1] Univ Michigan Hlth Syst, Dept Radiol, Div Intervent Neuroradiol, Ann Arbor, MI 48109 USA
[2] Univ Chicago, Med Ctr, Dept Radiol, Chicago, IL 60637 USA
[3] Univ Chicago, Med Ctr, Dept Neurol, Chicago, IL 60637 USA
[4] Univ Chicago, Med Ctr, Dept Surg, Chicago, IL 60637 USA
[5] Univ Michigan Hlth Syst, Dept Pathol, Ann Arbor, MI USA
[6] Johns Hopkins Univ & Hosp, Dept Radiol, Div Intervent Neuroradiol, Baltimore, MD 21287 USA
[7] Johns Hopkins Univ & Hosp, Dept Neurol, Div Intervent Neuroradiol, Baltimore, MD 21287 USA
[8] Johns Hopkins Univ & Hosp, Dept Neurosurg, Div Intervent Neuroradiol, Baltimore, MD 21287 USA