An FDG PET brain study in a 68-year-old woman with progressive amnestic cognitive decline is most expected to show:

• A Frontotemporal hypometabolism with anterior cingulate involvement
• B Diffuse uniform cortical hypometabolism with cerebellar involvement
• C Occipital hypometabolism with relative sensorimotor sparing
• D Bilateral temporoparietal and posterior cingulate hypometabolism ✓

Explanation

Alzheimer disease produces symmetric bilateral temporoparietal hypometabolism with posterior cingulate involvement on FDG PET, often extending to precuneus and medial temporal regions. Frontotemporal dementia shows frontal and anterior temporal hypometabolism, occipital hypometabolism with sensorimotor sparing suggests dementia with Lewy bodies, and diffuse uniform hypometabolism is typical of metabolic or toxic encephalopathies rather than a specific degenerative pattern. This distributional difference is the diagnostic value of FDG PET in dementia work-up.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

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Written and medically reviewed by the StethoPrep medical team.