1. Department of Neurological Surgery, Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri
2. Departments of Neurological Surgery and Neurology, Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri
3. Department of Neurological Surgery, Interventional Neuroradiology Service, Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri