1. Department of Neurological Surgery, University of California, San Francisco, San Francisco, California
2. Department of Interventional Neuroradiology, University of California, San Francisco, San Francisco, California
3. Departments of Neurology and of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, California
4. Departments of Anesthesia and Perioperative Care, Neurological Surgery, and Neurology, Center for Cerebrovascular Research, University of California, San Francisco, San Francisco, California