Effect of Gradient Impulse Response Function-based corrections on High-resolution FID Rosette Spectroscopic Imaging at 7T

Motivation: To assess the effect of applying k-space corrections for high-resolution (2mm in-plane) two-dimensional rosette FID MRSI using the measured gradient impulse response functions (GIRF). Goal(s): To determine how applying GIRF-predicted k-spaces for all time points can improve the image reconstruction and quantitation accuracy of high-resolution MRSI, in which increased gradient performance is necessary. Approach: GIRF-corrected and uncorrected metabolite maps, metabolite-to-Cr ratios, and estimates of the Cramer-Rao lower bounds (CRLBs) were compared for phantom and in vivo acquisitions. Results: In vivo and phantom metabolite maps from GIRF-corrected reconstructions show a reduction in artifacts and fewer regions where the metabolite quantitation exceeded a 30% CRLB. Impact: GIRF-based corrections for high-resolution FID MRSI have scarcely been shown in the literature. Accounting for gradient imperfections using the GIRF is crucial for non-Cartesian MRSI, particularly for high field and high-resolution acquisitions that demand high gradient performance.