title: Structural and functional brain abnormalities place phenocopy frontotemporal dementia (FTD) in the FTD spectrum.
abstract: 'Phenocopy' frontotemporal dementia (phFTD) patients may clinically mimic the behavioral variant of FTD (bvFTD), but do not show functional decline or abnormalities upon visual inspection of routine neuroimaging. We aimed to identify abnormalities in gray matter (GM) volume and perfusion in phFTD and to assess whether phFTD belongs to the FTD spectrum. We compared phFTD patients with both healthy controls and bvFTD patients.
  
  
  
  Seven phFTD and 11 bvFTD patients, and 20 age-matched controls underwent structural T1-weighted magnetic resonance imaging (MRI) and 3D pseudo-continuous arterial spin labeling (pCASL) at 3T. Normalized GM (nGM) volumes and perfusion, corrected for partial volume effects, were quantified regionally as well as in the entire supratentorial cortex, and compared between groups taking into account potential confounding effects of gender and scanner.
  
  
  
  PhFTD patients showed cortical atrophy, most prominently in the right temporal lobe. Apart from this regional atrophy, GM volume was generally not different from either controls or from bvFTD. BvFTD however showed extensive frontotemporal atrophy. Perfusion was increased in the left prefrontal cortex compared to bvFTD and to a lesser extent to controls.
  
  
  
  PhFTD and bvFTD show overlapping cortical structural abnormalities indicating a continuum of changes especially in the frontotemporal regions. Together with functional changes suggestive of a compensatory response to incipient pathology in the left prefrontal regions, these findings are the first to support a possible neuropathological etiology of phFTD and suggest that phFTD may be a neurodegenerative disease on the FTD spectrum.
authors.affiliation: Department of Radiology, Erasmus MC-University Medical Center, Rotterdam, The Netherlands.
authors.forename: Rebecca M E
authors.initials: RME
authors.lastname: Steketee
authors.affiliation: Department of Radiology, Erasmus MC-University Medical Center, Rotterdam, The Netherlands.
authors.forename: Rozanna
authors.initials: R
authors.lastname: Meijboom
authors.affiliation: Biomedical Imaging Group Rotterdam, Departments of Medical Informatics and Radiology, Erasmus MC-University Medical Center, Rotterdam, The Netherlands.
authors.forename: Esther E
authors.initials: EE
authors.lastname: Bron
authors.affiliation: Department of Psychiatry, Erasmus MC-University Medical Center, Rotterdam, The Netherlands.
authors.forename: Robert Jan
authors.initials: RJ
authors.lastname: Osse
authors.affiliation: Department of Neurology, Erasmus MC-University Medical Center, Rotterdam, The Netherlands.
authors.forename: Inge
authors.initials: I
authors.lastname: de Koning
authors.affiliation: Department of Neurology, Erasmus MC-University Medical Center, Rotterdam, The Netherlands.
authors.forename: Lize C
authors.initials: LC
authors.lastname: Jiskoot
authors.affiliation: Biomedical Imaging Group Rotterdam, Departments of Medical Informatics and Radiology, Erasmus MC-University Medical Center, Rotterdam, The Netherlands.
authors.forename: Stefan
authors.initials: S
authors.lastname: Klein
authors.affiliation: Department of Neurology, Erasmus MC-University Medical Center, Rotterdam, The Netherlands.
authors.forename: Frank Jan
authors.initials: FJ
authors.lastname: de Jong
authors.affiliation: Department of Radiology, Erasmus MC-University Medical Center, Rotterdam, The Netherlands.
authors.forename: Aad
authors.initials: A
authors.lastname: van der Lugt
authors.affiliation: Department of Neurology, Erasmus MC-University Medical Center, Rotterdam, The Netherlands.
authors.forename: John C
authors.initials: JC
authors.lastname: van Swieten
authors.affiliation: Department of Radiology, Erasmus MC-University Medical Center, Rotterdam, The Netherlands. Electronic address: marion.smits@erasmusmc.nl.
authors.forename: Marion
authors.initials: M
authors.lastname: Smits
mesh_terms: D000368:Aged; D001921:Brain / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D001931:Brain Mapping; D016022:Case-Control Studies; D002560:Cerebrovascular Circulation / Q000502:physiology*; D005260:Female; D005500:Follow-Up Studies; D057180:Frontotemporal Dementia / Q000000981:diagnostic imaging / Q000473:pathology*; D066128:Gray Matter / Q000000981:diagnostic imaging / Q000473:pathology; D006801:Humans; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D011569:Psychiatric Status Rating Scales; D013113:Spin Labels
chemical_list: D013113:Spin Labels
keywords: Arterial spin labeling-MRI; Behavioral variant frontotemporal dementia; Cerebral blood flow; Gray matter volume; Phenocopy frontotemporal dementia