Mapping of cerebral metabolite concentrations in brain tumors using 1H-MRSI and quantitative MRI

Motivation: Absolute quantification of the 1H MRS metabolites remains a challenge for 2D MRSI, due to long acquisition times for the unsuppressed water reference and the multiple biases present due to relaxation and inhomogeneity. Goal(s): To propose a water reference method combining single voxel STEAM and quantitative MRI (qMRI). Approach: The method is demonstrated and tested against a standard water referencing method on one healthy subject. Its application is demonstrated in a brain tumor patient. Results: Apart from obtaining absolute metabolite concentrations, corrected for all water relaxation times, 4 qMRI maps (PD, T1, T2* and QSM) maps are also generated. Impact: We propose a method for absolute quantification of cerebral metabolites in 2D MRSI by combining STEAM and quantitative MRI. The method is tested against a reference method in a healthy subject and its application demonstrated for a brain tumor patient.