From the Departments of Radiology (A.S.K., K.A.P., M.A.M., J.D.K., F.A.G., T.M.), Psychiatry (J.T.O.), and Clinical Neurosciences (J.B.R.), University of Cambridge, Hills Road, Cambridge CB2 0QQ, England; and Departments of Radiology (O.I.V., F.A.G., T.M.) and Neurology (J.B.R.), Cambridge University Hospitals NHS Foundation Trust, Cambridge, England.