Imaging correlations of tau, amyloid, metabolism, and atrophy in typical and atypical Alzheimer's disease.

INTRODUCTION: Neuroimaging modalities can measure different aspects of the disease process in Alzheimer's disease, although the relationship between these modalities is unclear.
METHODS: We assessed subject-level regional correlations between tau on [18F]AV-1451 positron emission tomography (PET), β amyloid on Pittsburgh compound B PET, hypometabolism on [18F] fluorodeoxyglucose PET, and cortical thickness on magnetic resonance imaging in 96 participants with typical and atypical Alzheimer's disease presentations. We also assessed how correlations between modalities varied according to age, presenting syndrome, tau-PET severity, and asymmetry.
RESULTS: [18F]AV-1451 uptake showed the strongest regional correlation with hypometabolism. Correlations between [18F]AV-1451 uptake and both hypometabolism and cortical thickness were stronger in participants with greater cortical tau severity. In addition, age, tau asymmetry, and clinical diagnosis influenced the strength of the correlation between [18F]AV-1451 uptake and cortical thickness. DISCUSSION: These findings support a close relationship between tau and hypometabolism in Alzheimer's disease but show that correlations between neuroimaging modalities vary across participants.