1. Department of Neurology, University of California at San Francisco, San Francisco, California
2. Department of Neurosurgery, University of California at San Francisco, San Francisco, California
3. Department of Radiology, University of California at San Francisco, San Francisco, California
4. Departments of Neurology, Neurosurgery, Radiology, and Anesthesia & Perioperative Care, University of California at San Francisco, San Francisco, California