1 From the Department of Radiology & Nuclear Medicine (F.B.), VU University Medical Centre, Amsterdam, the Netherlands; and the Translational Neuroradiology Unit (D.S.R.), National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD. f.barkhof@vumc.nl.
2 From the Department of Radiology & Nuclear Medicine (F.B.), VU University Medical Centre, Amsterdam, the Netherlands; and the Translational Neuroradiology Unit (D.S.R.), National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD.