Validation of a continuous model of amyloid‐β CSF/PET discordance across cohorts and PET tracers

Recently, we provided evidence that discordance in CSF vs. PET amyloid‐β biomarkers represents a natural phase in the progression of amyloid‐β pathology, with either CSF or PET biomarkers becoming abnormal first, based on well‐validated cut‐offs. We found that CSF‐/PET+ individuals had lower prevalence of APOE‐ε4 genotype and slower rate of amyloid‐β PET accumulation compared with CSF+/PET‐ individuals [1]. Given the methodological limitations of binary cut‐offs, here we aimed to validate a continuous model of imbalance in CSF vs. PET amyloid‐β biomarkers across cohorts and tracers, and to investigate biological factors underlying discordance in CSF and PET results.