title: Reply.
authors.affiliation: Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital.|Harvard Medical School, Boston, MA.
authors.forename: Elena
authors.initials: E
authors.lastname: Herranz
authors.affiliation: Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital.|Harvard Medical School, Boston, MA.
authors.forename: Jacob M
authors.initials: JM
authors.lastname: Hooker
authors.affiliation: Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital.|Harvard Medical School, Boston, MA.
authors.forename: David
authors.initials: D
authors.lastname: Izquierdo-Garcia
authors.affiliation: Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital.|Harvard Medical School, Boston, MA.
authors.forename: Marco L
authors.initials: ML
authors.lastname: Loggia
authors.affiliation: Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital.|Harvard Medical School, Boston, MA.
authors.forename: Caterina
authors.initials: C
authors.lastname: Mainero
mesh_terms: D006801:Humans; D009103:Multiple Sclerosis; D049268:Positron-Emission Tomography