Quantitative susceptibility mapping, chi-separation (χ-separation), and their associations with cognitive functions in the UK Biobank study

Motivation: QSM and health outcomes were previously evaluated for QSM in subcortical regions. Furthermore, QSM is limited by its inability to distinguish iron and myelin. Goal(s): We expanded the construction of QSM to both cortical and subcortical regions and to apply a novel method (χ-separation) the separate iron and myelin content. We evaluated the associations of QSM and χ-separation with age and with cognitive function. Approach: We used multivariable linear regression models to evaluate the associations in the UK Biobank. Results: Higher QSM values in cortical regions were associated with poor memory and executive function. Higher χ-separation values were associated with poor prospective memory. Impact: Higher iron content in the brain may be associated with poor cognitive function. These associations need to be further investigated in longitudinal data sets to evaluate the progression of cognitive decline and neurodegenerative disease development.