*7.4. Multi-Contrast MRI*

Multi-contrast sequences may o ffer a novel alternative for eliminating the requirement of registration and resampling of separate scans while simultaneously reducing scan acquisition time (Figure 2) [152]. A recently developed multiparametric imaging sequence is the Multi Echo (ME) MP2RAGE, which is largely una ffected by B1 inhomogeneities [153–160]. This allows for the acquisition of T2\*-based contrasts from which subsequent SWI and quantitative susceptibility maps (QSM) can be created in the same space as the T1 images [158,160]. Other benefits of multiple contrasts is that they contain complimentary information that can be used to jointly denoise and improve the SNR of the acquired images [161–163].

**Figure 2.** Multi-contrast imaging. The top row shows MP2RAGE T1-weighted, T1, T2\*, and R2\* maps and a quantitative susceptibility map (QSM) image obtained at 7 T within a single multi echo (ME) MP2RAGE sequence. Below are a 3 T T1-weighted map, a T2\* map, and a QSM image, where each T1 and T2\* were obtained with di fferent sequences but were optimized to provide a contrast comparable to those obtainable at 7 T but without the inversions required for creating T1 maps. Both the 3 and 7 T images came from the same subject and are shown in the axial plane. The contrast and visibility of subcortical structures is indeed comparable across field strengths [164].
