1. Department of Neurology, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA;
2. Institute for Clinical and Translational Science, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA;
3. Department of Radiology, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA;
4. Department of Neurosurgery, The University of Texas Health Science Center at Houston, Houston, Texas, USA;
5. Department of Neurosurgery, University of Virginia Health System, Charlottesville, Virginia, USA;
6. Department of Neurosurgery, University of Washington, Seattle, Washington, USA;
7. Department of Neurosurgery, Washington University School of Medicine in Saint Louis, St. Louis, Missouri, USA;
8. Mallinckrodt Institute of Radiology, Washington University School of Medicine in Saint Louis, St. Louis, Missouri, USA;
9. Department of Neurosurgery, Mayo Clinic Hospital, Rochester, Minnesota, USA;
10. Department of Radiology, Mayo Clinic Hospital, Rochester, Minnesota, USA;
11. Department of Neurosurgery, University Hospital Southampton, NHS Foundation Trust, Southampton, UK;
12. Department of Neurosurgery, Mayo Clinic, Jacksonville, Florida, USA;
13. Department of Neurosurgery, University of Florida, Gainesville, Florida, USA;
14. Department of Neurosurgery, University of Pittsburgh Medical Center Health System, Pittsburgh, Pennsylvania, USA;
15. Department of Neurosurgery, University of Illinois Chicago, Chicago, Illinois, USA;
16. Department of Neurosurgery, University Hospitals Cleveland Medical Center/Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
17. Department of Neurosurgery, University of Miami, Coral Gables, Florida, USA;
18. Department of Neurosurgery, University of Groningen, Groningen, Netherlands;
19. Department of Neurosurgery, Tokushima University Hospital, Tokushima, Japan;
20. Department of Neurosurgery, University of California San Francisco, San Francisco, California, USA;
21. Department of Neurosurgery, Brigham and Women's Hospital, Boston, Massachusetts, USA;
22. Department of Neurosurgery, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA;