EVALUATION OF TAU DEPOSITION IN AMYLOID POSITIVE MCI OR MILD-AD DEMENTIA SUBJECTS FROM THE ELENBECESTAT MISSION AD PROGRAM USING [18 F]PI-2620 PET

I-VI ROIs or at a single Desikan-Killiany atlas ROI level when compared to CSF-/PETindividuals. However, both CSF+ participant groups had faster retrospective rates of CSF P-tau accrual than CSFparticipants (Figure 3). Conclusions: Supra-threshold CSF P-tau in the absence of flortaucipir abnormality may indicate an established AD-process without decline in cognitive functions and widespread tau pathology. Concordance of CSF/PET tau measures coincide with stronger cognitive decline. This therefore suggests that CSF P-tau abnormality may serve as an indicator of progressing AD pathophysiological processes prior to substantial cognitive impairment.