Quantitative MRI Correlates of Brain Non-heme Iron

Motivation: Multiple quantitative MR (qMR) metrics have been shown to be sensitive to brain iron. However, direct comparisons among these metrics and with histological iron data are limited. Goal(s): We aim to evaluate the effective (R2*) and irreversible (R2) transverse relaxation rates as well as quantitative susceptibility mapping (QSM) in quantifying non-heme brain iron levels. Approach: We tested associations among qMR metrics and iron content estimated from histologically determined trajectories of iron accumulation in healthy young individuals. Results: While all metrics showed sensitivity to iron content, R2* is more robust in its association with histological estimates of iron from literature. Impact: This study examined MRI-based measures of non-heme brain iron, providing valuable insights into their reliability as iron markers across brain tissue types and their correspondence with histology.