title: Differentiating the frontal presentation of Alzheimer's disease with FDG-PET.
abstract: BACKGROUND
  Alzheimer's disease (AD) can present with behavioral changes with this syndrome described as frontal variant AD (FvAD). Excess frontal pathology may explain this presentation. Neuroimaging with fluoro-deoxy-glucose positron emission tomography (FDG- PET) can be used to examine the effects of pathology in FvAD.
  
  
  METHODS
  We administered an assessment scale for frontal behavioral impairment, the Frontal Behavioral Inventory (FBI), to 53 patients with AD. Scores in the top quartile were defined as FvAD. FDG- PET was analyzed in 8 frontal regions.
  
  
  RESULTS
  The Z (SD) score for metabolism was significantly higher (indicating greater hypometabolism) in the FvAD group than the remaining AD group for combined left and right orbitofrontal regions (2.64 (SD 0.99) versus 2.11 (1.22), p < 0.03)) and combined left and right medial frontal regions (2.38 (0.63) versus 1.82 (0.88) p < 0.003) but insignificantly different in combined lateral frontal and superior frontal regions. Statistical parametric mapping revealed these frontal regions to be the only brain regions with significantly different metabolism between the FvAD and the remainder of the AD groups.
  
  
  CONCLUSIONS
  Medial and orbital frontal hypometabolism is greater in AD patients presenting with more frontal/behavioral features, likely reflecting a greater pathological load in these brain regions in FvAD patients. These frontal regions may be more linked to behavioral features than other frontal brain regions.
authors.affiliation: Austin Health Continuing Care Clinical Service Unit, Heidelberg, Victoria, Australia University of Melbourne, Melbourne, Victoria, Australia.
authors.forename: Michael C
authors.initials: MC
authors.lastname: Woodward
authors.affiliation: Austin Health Continuing Care Clinical Service Unit, Heidelberg, Victoria, Australia Austin Health Centre for PET, Heidelberg, Victoria, Australia.
authors.forename: Christopher C
authors.initials: CC
authors.lastname: Rowe
authors.affiliation: University of Melbourne, Melbourne, Victoria, Australia Austin Health Centre for PET, Heidelberg, Victoria, Australia.
authors.forename: Gareth
authors.initials: G
authors.lastname: Jones
authors.affiliation: University of Melbourne, Melbourne, Victoria, Australia Austin Health Centre for PET, Heidelberg, Victoria, Australia.
authors.forename: Victor L
authors.initials: VL
authors.lastname: Villemagne
authors.affiliation: Monash University, Monash, Victoria, Australia.
authors.forename: Tammie A
authors.initials: TA
authors.lastname: Varos
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000473:pathology*; D005260:Female; D019788:Fluorodeoxyglucose F18; D005625:Frontal Lobe / Q000000981:diagnostic imaging*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18
keywords: Alzheimer's disease; FDG- PET; Frontal Behavioral Inventory; behavioral features versus hypometabolism; degree of hypometabolism; frontal variant Alzheimer's disease; statistical parametric mapping