Improving EPI quality with GRAPPA in concurrent fMRI-fMRS at 7T

Motivation: To develop a sequence for high-quality concurrent measurement of BOLD signal changes (fMRI) and biochemicals metabolite concentrations (fMRS). Goal(s): To implement parallel imaging with inline image reconstruction to improve fMRI image quality in concurrent fMRI-fMRS experiments at 7 T. Approach: We modified an fMRS-fMRI sequence to start by acquiring reference lines for GRAPPA reconstruction. Then each TR consists of a semiLASER acquisition for single-voxel MRS, and a GRAPPA-accelerated 3D EPI acquisition. Results: We obtained sufficient tSNR (30) map for the 3D EPI and a high SNR (59) and a narrow linewidth (9 Hz) for the spectrum. Impact: The modified concurrent fMRI-fMRS pulse sequence enhances the fMRI component to enable whole-brain coverage, reduced distortion, and high spatial resolution, providing a powerful tool for neuroscientists to study the dynamics of neurochemicals simultaneous with the BOLD signal.