Detection of new resonances in the down-field 1H MRS of human calf muscle in vivo at 7T

We have detected new resonances that were not reported previously with chemical shifts of ~10.1, 10.3, and 10.9 ppm occurring in the down-field 1H MRS (DFMRS) from the human calf muscle in vivo. Based on the phantom and literature data, we speculate that the contribution to the 10.1 ppm peak might be from L-Tryptophan whereas the peaks at 10.3 and 10.9 ppm are yet to be assigned. This is for the first time that these peaks are observed and reported from the down-field 1H MRS of the human calf muscle.