In Vivo Characterization and Identification of Novel Resonances in the Downfield ¹H MRS of Human Skeletal Muscle/Calf Muscle at 3T

Motivation: Most previous downfield ¹H MRS studies have focused on brain metabolites, with relatively few investigations conducted on skeletal muscle. Goal(s): To characterize the downfield metabolites in human skeletal muscle in vivo at 3T. Approach: An optimized metabolite-cycled (MC)-sLASER was used to simultaneously measure the metabolites in the upfield and downfield regions of the skeletal muscle ¹H spectra. Results: We detected three new peaks at ~10.1, 11.3, 11.7 ppm in the downfield region of the ¹H MRS of skeletal muscle at 3T that were not reported previously alongside the common upfield/downfield metabolites such as carnosine, IMCL/EMCL, creatine, TMA. Impact: This is the first reported detection of new resonances at ~10.1, 11.3, and 11.7ppm in downfield of the ¹H MRS of skeletal muscle at 3T. This will be beneficial to study role of these metabolites in healthy and disease condition.