1. Interventional Neuroradiology Unit and
2. Neurosurgery Service, Hospital San Francisco Asis, Madrid;
3. Interventional Neuroradiology Section, Departments of Neurosurgery and Radiology, LSU Health Sciences Center, Shreveport, Louisiana
4. Interventional Neuroradiology Unit, Hospital Universitario Central de Asturias, Oviedo, Spain; and
5. Neurosurgery Service, Hospital Clinico San Carlos;