From the Department of Radiology (M.M.-B., D.K.S., D.K.H., D.S.H., N.B., C.Y.), Department of Neurology (K.J.B., D.L.T.), and Department of Surgery (T.H.), University of Washington, Seattle; and Department of Neurology, University of Utah, Salt Lake City (A.D.H.). (At 2017-11)