1. From the Departments of Radiology (Y.Y., G.Z.), Neurology (S.C., M.G.L., G.W.A.), and Electrical Engineering (J.O.), Stanford University, 1201 Welch Rd, PS-04, Mailcode 5488, Stanford, CA 94305-5488; and Department of Neurology, University of California, Los Angeles, Los Angeles, Calif (F.S., D.S.L.).