Tau Aggregation Correlates with Amyloid Deposition in Both Mild Cognitive Impairment and Alzheimer's Disease Subjects.

ABSTRACT

BACKGROUND: Amyloid plaque and tau-containing neurofibrillary tangles are important features of Alzheimer's disease (AD). However, the relationship between these processes is still debated. OBJECTIVE: We aimed to investigate local and distant relationships between tau and amyloid deposition in the cortex in mild cognitive impairment (MCI) and AD using PET imaging. METHODS: Seventy-nine subjects (51 controls, 13 amyloid-positive MCI subjects, and 15 amyloid positive AD subjects) underwent MRI and 18F-flutemetamol PET. All MCI/AD subjects and 8 healthy controls as well as 33 healthy control subjects from the ADNI dataset also had 18F-AV1451 PET. Regional and distant correlations were examined after sampling target-to-cerebellar ratio images. Biological parametric mapping was used to evaluate voxel level correlations locally. RESULTS: We found multiple clusters of voxels with highly significant positive correlations throughout the association cortex in both MCI and AD subjects. CONCLUSION: The multiple clusters of positive correlations indicate that tau and amyloid may interact locally and be involved in disease progression. Our findings suggest that targeting both pathologies may be required.