From the Department of Neurology, (D.U., R.P., R.O., G.P.S.), University of Sassari, Italy; University Hospital HM (M.H.G.M., J.A.P.P, R.M.F), CINAC, Madrid, Spain; and Neurodegeneration Imaging Group (D.U.), Institute of Psychiatry, Psychology and Neuroscience, King's College London, UK.