Fig. 3
Voxelwise associations between FTP-PET and p-tau217. The association between plasma p-tau217 and FTP-SUVR in each voxel was assessed using a simple regression model in each voxel (FTP-SUVRvoxel = β0 + β1*p-tau217). A Top-left: non-thresholded maps where β1 values indicate the increase in FTP-SUVR associated with an increase in 1 pg/mL of plasma p-tau217. Top-right: thresholded map showing clusters where the plasma-PET association was significant using the two pre-determined thresholds (uncorrected p < 0.001 and family-wise error corrected p < 0.05). B Non-thresholded β1 maps estimated in the 2 amyloid groups separately; same color scale as A. C interaction results, indicating significant differences between the two maps shown in panel B based on an uncorrected p < 0.001 threshold with a cluster size > 100 voxels. To illustrate these interactions and the direction of the PET-plasma associations, SUVR values were extracted from significant clusters and displayed on scatterplots. Clusters were color-coded to indicate the direction of the interactions; blue indicates regions of FTP-PET binding that were more strongly correlated with p-tau217 in patients with lower amyloid levels, here the temporal lobe, and orange indicates regions of FTP-PET binding that were more strongly correlated with p-tau217 in patients with higher amyloid levels, here the sensori-motor and visual cortices. Full 3-dimensional maps, including thresholded and non-thresholded images, are available on neurovault: https://neurovault.org/collections/NLWHVBKP/