Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 943065, USA.

Department of Radiology, Molecular Imaging Program at Stanford, Stanford University, Stanford, CA 943065, USA.

Department of Radiology, Molecular Imaging Program at Stanford, Stanford University, Stanford, CA 943065, USA; Nuclear Technology Development Centre, National Nuclear Energy Commission, Belo Horizonte, MG 31270-901, Brazil.

Department of Radiology, Molecular Imaging Program at Stanford, Stanford University, Stanford, CA 943065, USA.

Department of Radiology, Molecular Imaging Program at Stanford, Stanford University, Stanford, CA 943065, USA.

Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 943065, USA; Department of Radiology, Molecular Imaging Program at Stanford, Stanford University, Stanford, CA 943065, USA.

Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 943065, USA; Department of Radiology, Molecular Imaging Program at Stanford, Stanford University, Stanford, CA 943065, USA.

Department of Radiology, Molecular Imaging Program at Stanford, Stanford University, Stanford, CA 943065, USA.

Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 943065, USA; Department of Radiology, Molecular Imaging Program at Stanford, Stanford University, Stanford, CA 943065, USA.

Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 943065, USA.

Department of Radiology, Molecular Imaging Program at Stanford, Stanford University, Stanford, CA 943065, USA. Electronic address: cbeinat@stanford.edu.