[1] Univ Calif San Francisco, Dept Neurol Surg, San Francisco, CA 94143 USA
[2] Univ Calif San Francisco, Dept Anesthesia & Perioperat Care, Cerebrovasc Res Ctr, San Francisco, CA 94143 USA
[3] Univ Calif San Francisco, Div Neurointervent Radiol, San Francisco, CA 94143 USA