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In vivo detection of 2‐hydroxyglutarate in brain tumors by optimized point‐resolved spectroscopy (PRESS) at 7T
Author(s) -
Ganji Sandeep K.,
An Zhongxu,
Tiwari Vivek,
McNeil Sarah,
Pinho Marco C.,
Pan Edward,
Mickey Bruce E.,
Maher Elizabeth A.,
Choi Changho
Publication year - 2017
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.26190
Subject(s) - in vivo , nuclear magnetic resonance , spectroscopy , in vivo magnetic resonance spectroscopy , nuclear magnetic resonance spectroscopy , point (geometry) , chemistry , nuclear medicine , medicine , physics , magnetic resonance imaging , biology , mathematics , radiology , microbiology and biotechnology , quantum mechanics , geometry
Purpose To test the efficacy of 7T MRS for in vivo detection of 2‐hydroxyglutarate (2HG) in brain tumors. Methods The subecho times of point‐resolved spectroscopy (PRESS) were optimized at 7T with density‐matrix simulations and phantom validation to improve the 2HG signal selectivity with respect to the neighboring resonances of γ‐aminobutyric acid (GABA), glutamate (Glu), and glutamine (Gln). MRS data were acquired from 12 subjects with gliomas in vivo and analyzed with LCModel using calculated basis spectra. Metabolite levels were quantified using unsuppressed short echo time (TE) water as a reference. Results The PRESS TE was optimized as TE = 78 ms (TE 1 = 58 ms and TE 2 = 20 ms), at which the 2HG 2.25 ppm resonance appeared as a temporally maximum inverted narrow peak and the GABA, Glu, and Gln resonances between 2.2 and 2.5 ppm were all positive peaks. The PRESS TE = 78 ms method offered improved discrimination of 2HG from Glu, Gln, and GABA when compared with short‐TE MRS. 2HG was detected in all patients enrolled in the study, the estimated 2HG concentrations ranging from 1.0 to 6.2 mM, with percentage standard deviation of 2%–7%. Conclusion Data indicate that the optimized MRS provides good selectivity of 2HG from other metabolite signals and may confer reliable in vivo detection of 2HG at relatively low concentrations. Magn Reson Med 77:936–944, 2017. © 2016 International Society for Magnetic Resonance in Medicine