Accelerated 3D Metabolite T1 Mapping Using Variable-Flip-Angle FID MRSI

Motivation: Metabolite T1 values are needed for T1 correction in short-TR MRSI data. Due to the prolonged scan time, metabolite T1 measurement has been limited to single-voxel or single-slice experiments so far. Goal(s): To develop a novel method for 3D metabolite T1 mapping in a practically feasible scan time. Approach: We used a variable-flip-angle short-TR MRSI to achieve rapid metabolite T1 mapping. The high-dimensional data space was undersampled in a variable-density manner. Associated data processing challenges were solved by generalized-series and low-rank-tensor modelling. Results: Simulation, phantom and healthy subject results demonstrated the feasibility of accelerated 3D metabolite T1 mapping. Impact: The proposed method enables 3D metabolite T1 mapping within a clinically feasible scan time (15 min). This method can be used to correct T1 weighting effects in accelerated short-TR MRSI experiments, producing more quantitative results.