Clifford J. Eskey, MD, PhD, is Director, Division of Neuroradiology and Director, Interventional Neuroradiology, Department of Radiology, at Dartmouth-Hitchcock Medical Center in Lebanon, New Hampshire. Clifford J. Belden, MD, Department of Radiology, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire. David A. Pastel, MD, Department of Radiology, Dartmouth-Hitchcock Medical Center, and Assistant Professor of Radiology, Dartmouth Medical School, in Lebanon, New Hampshire. Arastoo Vossough, MD, PhD, is Neuroradiologist and Assistant Professor of Radiology, Children's Hospital of Philadelphia and Hospital of the University of Pennsylvania, in Philadelphia, Pennsylvania. Albert J. Yoo, MD, is Staff, Interventional Neuroradiology, Massachusetts General Hospital and Instructor, Harvard Medical School, in Boston, Massachusetts.