Leveraging Voxel Spread Function approach to Improve R2* Mapping Accuracy at 7T MRI

Motivation: The macroscopic field inhomogeneities are proportional to the external magnetic field, poses significant challenges for quantifying the R2* from multi-gradient-recalled-echo (mGRE) MR sequences at 7T. Goal(s): This study aiming to demonstrates the effectiveness of the voxel spread function (VSF) method in mitigating artifacts on R2* caused by these inhomogeneities. Approach: Six healthy volunteers underwent MR scans at 7T (Terra Siemens). R2* values were obtained with and without VSF correction from both unfiltered and Hanning-filtered mGRE data. Results: The results showed that VSF correction significantly reduced the overestimation of R2*, proving its utility in accurate estimation of quantitative MR metrics at 7T. Impact: The voxel spread function (VSF) method shows great promise in correcting macroscopic magnetic field inhomogeneities in mGRE images, aiding in the accurate estimation of quantitative mGRE metrics such as R2* and myelin water fraction at ultra-high field MRI.