Figure 3.

Phosphorylated tau CSF epitopes and Aβ PET associations. Spearman rank correlations between CSF biomarkers and Aβ PET ([¹⁸F]AZD4694) across all groups show p-tau231 as having the highest correlation coefficient (a-c). The accuracy of CSF biomarkers in distinguishing Aβ PET status (positive vs negative) is evidenced by AUCs as shown in (d). T-parametric maps show the voxel-wise association between CSF biomarkers and [¹⁸F]AZD4694 in all participants (e) as well as within CI (f) and CU (g). Models were adjusted by age and sex and RFT was used to account for multiple comparisons (significant t-values > 3.1). The dot plot (h) shows the average slope (beta) values by ROI for each of the CSF biomarkers. The beta value was derived from linear models that had Aβ PET as the outcome measure, the CSF biomarkers were the predictors and the covariates were sex and age. These models were performed at the voxel level and the CSF p-tau beta values of each voxel were averaged within ROIs. Were included in the ROIs only the voxels that had a significant association between Aβ PET and all of the CSF biomarkers evaluated here. T-parametric maps (i) show the voxel-wise association between CSF biomarkers (p-tau231, p-tau217 and p-tau181) and [¹⁸F]AZD4694 in Aβ-negative CU subjects. Models were adjusted for age and sex and RFT was used to account for multiple comparisons (significant t-values > 3.1). In addition, CSF p-tau biomarkers were plotted (j) as a function of Aβ PET deposition (in Centiloids) in the CU group, which was used to infer AD pathology progression. Dashed line indicates the biomarker cut off for positivity. CU: cognitively unimpaired; CI: cognitively impaired.