Medium Term Reproducibility of 1H FID-CRT-MRSI at 7 Tesla

Motivation: 1H FID-CRT-MRSI at 7T is a promising approach for non-invasive quantification of metabolic processes in the brain. Its medium-term reproducibility has never been investigated even though it is a requirement for many potential study setups. Goal(s): To evaluate the intersession reproducibility of 1H FID-CRT-MRSI at 7T. Approach: We calculated metabolite concentration estimates in 55 brain regions for two measurement sessions one week apart, and determined coefficients of variations between them. Results: We found good overall reproducibility, with CVs ranging from 7.5% to 12% for different brain regions, and concentration estimates matching our previous work. Impact: We established good reproducibility of FID-CRT-MRSI at 7T, enabling longitudinal study setups e.g. for disease monitoring. Another potential follow-up of this work may be tracking the intra-day metabolite level variations in the brain in a non-invasive way.