1. From the Department of Radiology and Biomedical Imaging, Yale School of Medicine, 333 Cedar St, Box 208042, Tompkins East 2, New Haven, CT 06520-8042 (A.K., S.B., M.K., S.P., J.M., A.M.); Department of Neuroradiology, MD Anderson Cancer Center, Houston, Tex (M.W.); and Departments of Interventional Neuroradiology, Radiology, Nuclear Medicine, Neurology, and Neurosurgery, University of Maryland School of Medicine, Baltimore, Md (D.G.).