Box plots of relationship between imaging measurements (susceptibility, R2*, R2, and R2’) and number of 400× magnification high-power fields with (a) CD163 and (b) CD68 iron-containing macrophages. Significant positive correlations were found between the susceptibility, R2*, and R2’ (R2* – R2) values and the number of high-power fields with both CD163 (P < .01) and CD68 iron-containing macrophages (P value range, .01–.02). No significant correlation was found between R2 values and CD163 (P = .16) and CD68 (P = .32) iron-containing macrophages. Similar significance results were obtained with linear mixed models. Each open circle represents one tissue sample.