1. Georgetown University School of Medicine, Washington, DC, USA
2. Department of Neurosurgery, MedStar Georgetown University Hospital, Washington, DC, USA
3. Touro College of Osteopathic Medicine, New York, NY, USA
4. Department of Neurosurgery, MedStar Washington Hospital Center, Washington, DC, USA
5. Department of Radiology, MedStar Washington Hospital Center, Washington, DC, USA