1. Department of Diagnostic Imaging (R.A.M., M.V.J.), Warren Alpert School of Medicine at Brown University, Providence, RI.
2. Department of Neurology (R.A.M., M.V.J.), Warren Alpert School of Medicine at Brown University, Providence, RI.
3. Department of Neurosurgery (R.A.M., K.M.L., M.V.J.), Warren Alpert School of Medicine at Brown University, Providence, RI.
4. The Norman Prince Neuroscience Institute, Rhode Island Hospital, Providence (R.A.M., K.M.L., M.V.J.).
5. Department of Clinical Neurosciences, University of Calgary, Canada (J. M.O., M.G.).
6. Division of Neuroradiology, Clinic of Radiology and Nuclear Medicine, University Hospital Basel, University of Basel, Switzerland (J.M.O., M.-N. P.).
7. Division of Neurointerventional Radiology, Department of Radiology, University of Massachusetts Medical Center, Worcester (A.S.P.).
8. Department of Diagnostic and Interventional Neuroradiology, Klinikum rechts der Isar, Technical University of Munich, Germany (C.M.).
9. Department of Radiology, Seaman Family MR Research Centre, Foothills Medical Centre, Calgary, Canada (M.G.).