1. From the Department of Clinical Neurosciences (R.R.M., J.-C.B., E.A.W.), Wolfson Brain Imaging Centre (D.I.-G., T.D.F.), Department of Radiology (M.J.G., J.H.G.), and Division of Cardiovascular Medicine (J.H.F.R., P.L.W.), University of Cambridge, Cambridge, UK; and Department of Neurology (R.R.M.), Ain Shams University, Cairo, Egypt.