1. Department of Radiology, New York Presbyterian Hospital, Weill Medical College of Cornell University, New York, New York
2. University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
3. Department of Neurosurgery, New York Presbyterian Hospital, Weill Medical College of Cornell University, New York, New York
4. University of Pennsylvania, Philadelphia, Pennsylvania
5. Departments of Neurosurgery and Radiology, New York Presbyterian Hospital, Weill Medical College of Cornell University, New York, New York