1. Oregon Health Sciences University School of Medicine Allegheny General Hospital, Pittsburgh, Pennsylvania
2. Department of Radiology Allegheny General Hospital, Pittsburgh, Pennsylvania
3. Oregon Health Sciences University, Portland, Oregon, and Departments of Neurosurgery and Radiology Allegheny General Hospital, Pittsburgh, Pennsylvania
4. Division of Neurosurgery Allegheny General Hospital, Pittsburgh, Pennsylvania
5. Dotter Interventional Institute Allegheny General Hospital, Pittsburgh, Pennsylvania