In vivo measurement of glycine with short echo-time 1H MRS in human brain at 7 T

ObjectTo determine whether glycine can be measured at 7 T in human brain with 1H magnetic resonance spectroscopy (MRS).Materials and methodsThe glycine singlet is overlapped by the larger signal of myo-inositol. Density matrix simulations were performed to determine the TE at which the myo-inositol signal was reduced the most, following a single spin-echo excitation. 1H MRS was performed on an actively shielded 7 T scanner, in five healthy volunteers.ResultsAt the TE of 30 ms, the myo-inositol signal intensity was substantially reduced. Quantification using LCModel yielded a glycine-to-creatine ratio of 0.14 ± 0.01, with a Cramér–Rao lower bound (CRLB) of 7 ± 1%. Furthermore, quantification of metabolites other than glycine was possible as well, with a CRLB mostly below 10%.ConclusionIt is possible to detect glycine at 7 T in human brain, at the short TE of 30 ms with a single spin-echo excitation scheme.

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