Figure 2. Quantitative maps estimated using MT modeling with standard and proposed R1b in a healthy volunteer. (a) MPF and R1f. As predicted by simulations (Fig. 1b), standard R1f is dominated by macromolecular content and therefore resembles MPF. The proposed R1f is much more uniform, likely due to removing the effects of MPF. Note slightly elevated values in the basal ganglia, likely due to iron accumulation. (b) Error between the proposed and standard MPF. Note its high variability with macromolecular content and B1 field (c), also consistent with simulations (Fig. 1a).

Figure 4. Quantitative mapping in an MS subject. (a) Proposed R1f is elevated in deep GM. The increase is consistent with the known distribution of iron in these regions, including areas with high (globus pallidus, #1), medium (putamen, #2), and low (thalamus, #3) iron content. Note elevated R1f in areas affected by diffuse lesional changes (#4) (as seen on T2-FLAIR and MPF). (b) The R1f is increased on the rim of the heavily demyelinated lesion (as revealed by MPF) (#1) and in WM areas affected by more diffuse disease (#2). (c) Example of a lesion without noticeable increase in R1f.