title: Positron emission tomography in asymptomatic gene carriers of Machado-Joseph disease.
abstract: OBJECTIVE
  The metabolic changes in the brain of symptomatic subjects affected with Machado-Joseph disease have been previously documented using PET with fluorine-18-fluorodeoxyglucose (FDG). The aim of this study was to evaluate these changes in asymptomatic Machado-Joseph disease gene carriers.
  
  
  METHODS
  Seven asymptomatic Machado-Joseph disease gene carriers, identified using a molecular test, and 10 normal control subjects were recruited for PET studies using FDG. Regional uptake ratios of FDG were calculated from the radioactivity of the cerebellar hemispheres, brainstem, and the temporal, parietal and occipital cortices, divided by the activity in the thalamus.
  
  
  RESULTS
  In comparison with data obtained from normal control subjects, there was significantly decreased FDG utilisation in the cerebellar hemispheres, brainstem, and occipital cortex, and increased FDG metabolism in the parietal and temporal cortices of asymptomatic Machado-Joseph disease gene carriers, suggesting preclinical disease activity. Discriminant analysis of regional FDG uptake correctly classified genetic status (Machado-Joseph disease mutation carriers v mutation negative subjects) in 25 of 25 subjects (100% sensitivity and 100% specificity), and clinical status (asymptomatic mutation carriers v symptomatic patients) in 14 of 15 subjects (100% sensitivity and 85.7% specificity).
  
  
  CONCLUSIONS
  Subclinical changes of FDG consumption, as measured by noninvasive PET, can act as an objective marker of preclinical disease activity in Machado-Joseph disease.
authors.affiliation: Department of Neurology, National Yang-Ming University School of Medicine and National Defense Medical Center, Taipei, Taiwan, Republic of China. bwsoong@vghtpe.gov.tw
authors.forename: B W
authors.initials: BW
authors.lastname: Soong
authors.forename: R S
authors.initials: RS
authors.lastname: Liu
mesh_terms: D000293:Adolescent; D000328:Adult; D015415:Biomarkers; D001921:Brain / Q000000981:diagnostic imaging / Q000378:metabolism*; D001923:Brain Chemistry; D016022:Case-Control Studies; D016002:Discriminant Analysis; D019788:Fluorodeoxyglucose F18; D006579:Heterozygote; D006801:Humans; D017827:Machado-Joseph Disease / Q000000981:diagnostic imaging* / Q000235:genetics / Q000378:metabolism*; D008875:Middle Aged; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014055:Tomography, Emission-Computed
chemical_list: D015415:Biomarkers; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18