Figure 4. Cortical amyloid as detected by PET PIB and its relationship to CSF tau and ptau₁₈₁ and the ratios of CSF tau/Aβ₄₂ and ptau₁₈₁/Aβ₄₂ in CDR 0 participants (n = 189).

A linear relationship is observed between the amount of cortical amyloid and

1. the levels of CSF tau
2. the levels of CSF ptau₁₈₁
3. the ratios of CSF tau/Aβ₄₂ and
4. the ratios of the ptau₁₈₁/Aβ₄₂. The correlations between the CSF tau(s)/Aβ₄₂ ratios and MCBP remain significant even when the statistical outlier (high PIB, high ratio) is omitted from the analysis (tau/Aβ₄₂, r = 0.74227, p < 0.0001; ptau₁₈₁/Aβ₄₂, r = 0.73510, p < 0.0001). All Pearson correlation coefficients are corrected for age.