title: Brain changes within the visuo-spatial attentional network in posterior cortical atrophy.
abstract: Posterior cortical atrophy (PCA) is characterized by basic visual and high order visual-spatial dysfunctions. In this study, we investigated long-distance deafferentation processes within the frontal-parietal-occipital network in ten PCA patients using a MRI-PET combined approach. Objective voxel-based [18F]FDG-PET imaging measured metabolic changes in single patients. Comprehensive investigation of diffusion tensor imaging (DTI) metrics and grey-matter density with voxel-based morphometry were obtained in a subgroup of 6 patients. Fractional anisotropy in the superior longitudinal fasciculus correlated with the PET metabolic changes within the inferior parietal and frontal eye field regions. [18F]FDG-PET analysis showed in each PCA case the typical bilateral hypometabolic pattern, involving posterior temporal, parietal, and occipital cortex, with additional hypometabolic foci in the frontal eye fields. Voxel-based morphometry showed right-sided atrophy in the parieto-occipital cortex, as well as a limited temporal involvement. DTI revealed extensive degeneration of the major anterior-posterior connecting fiber bundles and of commissural frontal lobe tracts. Microstructural measures in the superior longitudinal fasciculus were correlated with the PET metabolic changes within the inferior parietal and frontal eye field regions. Our results confirmed the predominant occipital-temporal and occipital-parietal degeneration in PCA patients. [18F]FDG-PET and DTI-MRI combined approaches revealed neurodegeneration effects well beyond the classical posterior cortical involvement, most likely as a consequence of deafferentation processes within the occipital-parietal-frontal network that could be at the basis of visuo-perceptual, visuo-spatial integration and attention deficits in PCA.
authors.affiliation: Universitá Vita-Salute San Raffaele, Milan, Italy Clinical Neuroscience Department, San Raffaele Hospital, Milan, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Cerami
authors.affiliation: Universitá Vita-Salute San Raffaele, Milan, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Crespi
authors.affiliation: Universitá Vita-Salute San Raffaele, Milan, Italy Istituto di Bioimmagini e Fisiologia Molecolare C.N.R., Segrate, Italy.
authors.forename: Pasquale Anthony
authors.initials: PA
authors.lastname: Della Rosa
authors.affiliation: Universitá Vita-Salute San Raffaele, Milan, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Dodich
authors.affiliation: Clinical Neuroscience Department, San Raffaele Hospital, Milan, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Marcone
authors.affiliation: Department of Neurological, Institute of Experimental Neurology-INSPE, San Raffaele Hospital, Milan, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Magnani
authors.affiliation: Department of Neurological, Institute of Experimental Neurology-INSPE, San Raffaele Hospital, Milan, Italy.
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Coppi
authors.affiliation: Universitá Vita-Salute San Raffaele, Milan, Italy Department of Neuroradiology, CERMAC, San Raffaele Hospital, Milan, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Falini
authors.affiliation: Istituto Universitario di Studi Superiori, Pavia, Italy.
authors.forename: Stefano F
authors.initials: SF
authors.lastname: Cappa
authors.affiliation: Universitá Vita-Salute San Raffaele, Milan, Italy Istituto di Bioimmagini e Fisiologia Molecolare C.N.R., Segrate, Italy Department of Nuclear Medicine, Division of Neuroscience, San Raffaele Hospital, Milan, Italy.
authors.forename: Daniela
authors.initials: D
authors.lastname: Perani
mesh_terms: D000368:Aged; D001284:Atrophy / Q000150:complications / Q000473:pathology; D001289:Attention Deficit Disorder with Hyperactivity / Q000209:etiology*; D002540:Cerebral Cortex / Q000000981:diagnostic imaging / Q000473:pathology*; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008609:Mental Status Schedule; D008875:Middle Aged; D019636:Neurodegenerative Diseases / Q000150:complications* / Q000473:pathology*; D009483:Neuropsychological Tests; D010468:Perceptual Disorders / Q000209:etiology*; D010775:Photic Stimulation; D049268:Positron-Emission Tomography; D013028:Space Perception / Q000502:physiology*
chemical_list: D019788:Fluorodeoxyglucose F18
keywords: Dementia; [${18}^F$]FDG-PET imaging; diffusion tensor imaging; frontal eye field; posterior cortical atrophy; voxel-based morphometry