title: Mapping brain morphological and functional conversion patterns in predementia late-onset bvFTD.
abstract: OBJECTIVE
  The diagnosis of behavioural variant frontotemporal dementia (bvFTD) is challenging during the predementia stage when symptoms are subtle and confounding. Morphological and functional neuroimaging can be particularly helpful during this stage but few data are available.
  
  
  METHODS
  We retrospectively selected 25 patients with late-onset probable bvFTD. Brain structural MRI and FDG PET were performed during the predementia stage (mean MMSE score 27.1 ± 2.5) on average 2 years before. The findings with the two imaging modalities were compared (SPM8) with those in a group of 20 healthy subjects. The bvFTD patients were divided into two subgroups: those with predominant disinhibition (bvFTD+) and those with apathy (bvFTD-).
  
  
  RESULTS
  Hypometabolism exceeded grey matter (GM) density reduction in terms of both extension and statistical significance in all comparisons. In the whole bvFTD group, hypometabolism involved the bilateral medial, inferior and superior lateral frontal cortex, anterior cingulate, left temporal and right parietal cortices and the caudate nuclei. GM density reduction was limited to the right frontal cortex and the left medial temporal lobe. In bvFTD+ patients hypometabolism was found in the bilateral medial and basal frontal cortex, while GM reduction involved the left anterior cingulate and left inferior frontal cortices, and the right insula. In bvFTD- patients, atrophy and mainly hypometabolism involved the lateral frontal cortex and the inferior parietal lobule.
  
  
  CONCLUSIONS
  These findings suggest that hypometabolism is more extensive than, and thus probably precedes, atrophy in predementia late-onset bvFTD, underscoring different topographic involvement in disinhibited and apathetic presentations. If confirmed in a larger series, these results should prompt biomarker operationalization in bvFTD, especially for patient selection in therapeutic clinical trials.
authors.affiliation: Nuclear Medicine Unit, Department of Health Science (DISSAL), University of Genoa and IRCCS AOU San Martino-IST, Largo R. Benzi 10, 16132, Genoa, Italy. Silviadaniela.morbelli@hsanmartino.it.
authors.forename: Silvia
authors.initials: S
authors.lastname: Morbelli
authors.affiliation: Clinical Neurology, Department of Neuroscience (DINOGMI), University of Genoa and IRCCS AOU San Martino-IST, Genoa, Italy.
authors.forename: Michela
authors.initials: M
authors.lastname: Ferrara
authors.affiliation: Nuclear Medicine Unit, Department of Health Science (DISSAL), University of Genoa and IRCCS AOU San Martino-IST, Largo R. Benzi 10, 16132, Genoa, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Fiz
authors.affiliation: Clinical Neurology, Department of Neuroscience (DINOGMI), University of Genoa and IRCCS AOU San Martino-IST, Genoa, Italy.
authors.forename: Barbara
authors.initials: B
authors.lastname: Dessi
authors.affiliation: Clinical Neurology, Department of Neuroscience (DINOGMI), University of Genoa and IRCCS AOU San Martino-IST, Genoa, Italy.
authors.forename: Dario
authors.initials: D
authors.lastname: Arnaldi
authors.affiliation: Clinical Neurology, Department of Neuroscience (DINOGMI), University of Genoa and IRCCS AOU San Martino-IST, Genoa, Italy.
authors.forename: Agnese
authors.initials: A
authors.lastname: Picco
authors.affiliation: Nuclear Medicine Unit, Department of Health Science (DISSAL), University of Genoa and IRCCS AOU San Martino-IST, Largo R. Benzi 10, 16132, Genoa, Italy.
authors.forename: Irene
authors.initials: I
authors.lastname: Bossert
authors.affiliation: Nuclear Medicine Unit, Department of Health Science (DISSAL), University of Genoa and IRCCS AOU San Martino-IST, Largo R. Benzi 10, 16132, Genoa, Italy.
authors.forename: Ambra
authors.initials: A
authors.lastname: Buschiazzo
authors.affiliation: Clinical Neurology, Department of Neuroscience (DINOGMI), University of Genoa and IRCCS AOU San Martino-IST, Genoa, Italy.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Accardo
authors.affiliation: Nuclear Medicine Unit, Department of Health Science (DISSAL), University of Genoa and IRCCS AOU San Martino-IST, Largo R. Benzi 10, 16132, Genoa, Italy.
authors.forename: Lorena
authors.initials: L
authors.lastname: Picori
authors.affiliation: Clinical Neurology, Department of Neuroscience (DINOGMI), University of Genoa and IRCCS AOU San Martino-IST, Genoa, Italy.|Clinical Psychology, Department of Neuroscience (DINOGMI), University of Genoa and IRCCS AOU San Martino-IST, Genoa, Italy.
authors.forename: Nicola
authors.initials: N
authors.lastname: Girtler
authors.affiliation: Medical Genetics, Department of Neuroscience (DINOGMI), University of Genoa and IRCCS AOU San Martino-IST, Genoa, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Mandich
authors.affiliation: Institute of Cognitive Sciences and Technologies, CNR, Rome, Italy.|Department of Nuclear Medicine, Karolinska Hospital, Stockholm, Sweden.
authors.forename: Marco
authors.initials: M
authors.lastname: Pagani
authors.affiliation: Nuclear Medicine Unit, Department of Health Science (DISSAL), University of Genoa and IRCCS AOU San Martino-IST, Largo R. Benzi 10, 16132, Genoa, Italy.
authors.forename: Gianmario
authors.initials: G
authors.lastname: Sambuceti
authors.affiliation: Clinical Neurology, Department of Neuroscience (DINOGMI), University of Genoa and IRCCS AOU San Martino-IST, Genoa, Italy.
authors.forename: Flavio
authors.initials: F
authors.lastname: Nobili
mesh_terms: D000368:Aged; D001284:Atrophy / Q000000981:diagnostic imaging; D001921:Brain / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology*; D001931:Brain Mapping; D016022:Case-Control Studies; D005260:Female; D019788:Fluorodeoxyglucose F18; D057180:Frontotemporal Dementia / Q000000981:diagnostic imaging* / Q000473:pathology / Q000503:physiopathology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D049268:Positron-Emission Tomography
chemical_list: D019788:Fluorodeoxyglucose F18
keywords: Brain PET; Frontotemporal dementia; Mild cognitive impairment