1. Stony Brook University Medical Center, Department of Neurosurgery, Cerebrovascular Center, Stony Brook, New York
2. Departments of Neuroradiology and Neurosurgery, Case Western Reserve University, University Hospitals of Cleveland, Cleveland, Ohio
3. University Hospitals of Cleveland, Case Western Reserve University, Departments of Neuroradiology and Neurosurgery, Cleveland, Ohio
4. Departments of Neuroradiology and Neurosurgery, New York University, New York, New York