Positron emission tomography in asymptomatic gene carriers of Machado-Joseph disease
- aDepartment of Neurology, National Yang-Ming University School of Medicine and National Defense Medical Center, Taipei, Taiwan, 11217, Republic of China, bNeurological Institute, Veterans General Hospital-Taipei, Taipei, Taiwan, 11217, Republic of China, cNational PET/Cyclotron Center, Veterans General Hospital-Taipei, Taiwan, 11217, Republic of China
- Dr Bing-wen Soong, Neurological Institute, Veterans General Hospital-Taipei, Taipei, Taiwan, 11217, Republic of China. Telephone 886-2-2872 3307; fax 886-2-2874 8631; email
- Received 1 July 1997
- Revised 3 November 1997
- Accepted 12 November 1997
OBJECTIVES 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 MachadoJoseph 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 carriersv symptomatic patients) in 14 of 15 subjects (100% sensitivity and 85.7% specificity).
CONCLUSION Subclinical changes of FDG consumption, as measured by non-invasive PET, can act as an objective marker of preclinical disease activity in Machado-Joseph disease.