Stepan Capek1,2, Kimberly K Amrami3, Benjamin M Howe3, Robert J Spinner4. 1. Department of Neurosurgery, Mayo Clinic, Rochester, Minnesota. 2. International Clinical Research Center, St. Anne's University Hospital Brno, Brno, Czech Republic. 3. Department of Radiology, Mayo Clinic, Rochester, Minnesota. 4. Department of Neurosurgery, Mayo Clinic, Rochester, MN.