1. Department of Neurological Surgery, Ohio State University Wexner Medical Center, Columbus, Ohio;
2. Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke;
3. Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, Florida; and
4. Biomedical Engineering and Physical Science Resource, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, Maryland;
5. Department of Neurological Surgery, University of Virginia Health Sciences Center, University of Virginia, Charlottesville, Virginia