Applied Radiology

Diagnosis

  Alzheimer’s disease

Findings

Axial FDG-PET images show relative hypometabolism in the temporal and posterior parietal lobes, confirmed on whole brain MIP image projected in the sagittal plane.

Discussion

Alzheimer’s disease (AD) is the most common cause of dementia with increasing prevalence as United States and world populations age. The disease is characterized clinically by memory impairment and progressive dysfunction in cognition with personality changes late in the course.  Pathologically, neurofibrillary tangles, senile plaques, and amyloid angiopathy are seen with disruption of axonal membranes.

Traditional imaging modalities are insensitive for early disease and may demonstrate nonspecific atrophy late in the disease course. Functional imaging with FDG PET has increased both sensitivity and specificity for AD when characteristic temporoparietal hypometabolism is observed.

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