Reproducibility, reliability and variability of FA and MD in the older healthy population: A test-retest multiparametric analysis

• In older healthy subjects, FA and MD show overall good test-retest reliability & reproducibility. • MD is sistematically more reproducible than FA across the entire brain anatomy. • FA is more reliable than MD in subcortical white matter regions. • In high reliability & low reproducibility regions, variability between subjects is high and statistical power is low. • In low reliability & high reproducibility regions, variability between subjects is low and statistical power is high.