Longitudinal reproducibility of 3D-FID-CRT-MRSI in the human brain at 3T and 7T

Motivation: A direct comparison of the longitudinal reproducibility of 3D FID-CRT-MRSI across 3T and 7T has not been performed. Goal(s): The aim was to determine the consistency of MRSI across these two field strengths in different brain regions. Approach: The same subjects were scanned twice within a week at both fields and intra-subject and inter-subject Coefficients of Variation (CV%) for three metabolite ratios in different brain regions were calculated. Results: The study found high reproducibility (CVs for most ROIs <10%) for both fields. 3T can provide sufficiently reproducible results by using larger voxel sizes and shorter measurement times. Impact: The results will impact researchers and clinicians using MRSI, providing them with a reproducible technique at a clinical field strength of 3Tand7T and can be a method for those focusing on larger brain regions or longitudinal monitoring of metabolite changes.