1. Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
2. Department of Neurosurgery, Virginia Commonwealth University School of Medicine, Richmond, VA, USA
3. Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
4. Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
5. Department of Pathology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA