In vivo estimation of transverse relaxation time constant (T₂) of 17 human brain metabolites at 3T

Purpose: The transverse relaxation times T₂ of 17 metabolites in vivo at 3T is reported and region specific differences are addressed. Methods: An echo-time series protocol was applied to one, two, or three volumes of interest with different fraction of white and gray matter including a total number of 106 healthy volunteers and acquiring a total number of 128 spectra. The data were fitted with the 2D fitting tool ProFit2, which included individual line shape modeling for all metabolites and allowed the T₂ calculation of 28 moieties of 17 metabolites. Results: The T₂ of 10 metabolites and their moieties have been reported for the first time. Region specific T₂ differences in white and gray matter enriched tissue occur in 16 of 17 metabolites examined including single resonance lines and coupled spin systems. Conclusion: The relaxation time T₂ is regions specific and has to be considered when applying tissue composition correction for internal water referencing. Magn Reson Med 80:452–461, 2018.