Purpose To evaluate the T<inf>2</inf> relaxation time of lactate (Lac) in brain tumors and the correlation of the T<inf>2</inf> and concentration with tumor grades. Methods Eight pairs of the subecho time sets of point-resolved spectroscopy were selected between 58 and 268 ms, with numerical and phantom analyses, for Lac T<inf>2</inf> measurement. In vivo spectra were acquired from 24 subjects with gliomas (13 low grade and 11 high grade) and analyzed with LCModel using numerically-calculated basis spectra. The metabolite T<inf>2</inf> relaxation time was obtained from monoexponential fitting of the multi-echo time (TE) signal estimates versus TE. The metabolite concentration was estimated from the zero-TE extrapolation of the T<inf>2</inf> fits. Results The Lac T<inf>2</inf> was estimated to be approximately 240 ms, without a significant difference between low and high grade tumors. The Lac concentration was estimated to be 4.1±3.4 and 7.0±4.7 mM for low and high grades respectively, but the difference was not significant. Conclusion The Lac T<inf>2</inf> was similar among gliomas regardless of their tumor grades. This suggests that the T<inf>2</inf> value from this study may be applicable to obtain the T<inf>2</inf> relaxation-free estimates of Lac in a subset of brain tumors. Magn Reson Med 73:2094-2099, 2015.
- <sup>1</sup>H MRS
- brain tumors
- PRESS (point-resolved spectroscopy)
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging