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Proton T 2 measurement and quantification of lactate in brain tumors by MRS at 3 Tesla in vivo
Author(s) -
Madan Akshay,
Ganji Sandeep K.,
An Zhongxu,
Choe Kevin S.,
Pinho Marco C.,
Bachoo Robert M.,
Maher Elizabeth M.,
Choi Changho
Publication year - 2015
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.25352
Subject(s) - in vivo , nuclear magnetic resonance , metabolite , nuclear medicine , t2 relaxation , imaging phantom , relaxation (psychology) , echo time , extrapolation , chemistry , mathematics , physics , medicine , magnetic resonance imaging , biology , radiology , statistics , microbiology and biotechnology
Purpose To evaluate the T 2 relaxation time of lactate (Lac) in brain tumors and the correlation of the T 2 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 2 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 2 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 2 fits. Results The Lac T 2 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 2 was similar among gliomas regardless of their tumor grades. This suggests that the T 2 value from this study may be applicable to obtain the T 2 relaxation‐free estimates of Lac in a subset of brain tumors. Magn Reson Med 73:2094–2099, 2015. © 2014 Wiley Periodicals, Inc.