1 From the Departments of Neurology (A.A.L., R.D.) and Radiology and Medical Imaging (J.A.M.), University of Virginia, Charlottesville. aa9qu@hscmail.mcc.virginia.edu.
2 From the Departments of Neurology (A.A.L., R.D.) and Radiology and Medical Imaging (J.A.M.), University of Virginia, Charlottesville.