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Glutamate quantification in patients with supratentorial gliomas using chemical shift imaging
Author(s) -
Liubinas S. V.,
Drummond K. J.,
Desmond P. M.,
Bjorksten A.,
Morokoff A. P.,
Kaye A. H.,
O'Brien T. J.,
Moffat B. A.
Publication year - 2014
Publication title -
nmr in biomedicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.278
H-Index - 114
eISSN - 1099-1492
pISSN - 0952-3480
DOI - 10.1002/nbm.3095
Subject(s) - in vivo , ex vivo , glutamate receptor , creatine , epilepsy , excitotoxicity , glioma , chemistry , in vivo magnetic resonance spectroscopy , medicine , nuclear medicine , magnetic resonance imaging , pathology , biology , biochemistry , cancer research , radiology , receptor , microbiology and biotechnology , psychiatry
This study aimed to evaluate and validate chemical shift imaging (CSI) for in vivo glutamate (Glu) quantification in patients with supratentorial gliomas. If validated, CSI could become an extremely useful tool to investigate metabolic dysfunction of Glu in excitotoxic neuropathologies. Quantitative CSI estimates of Glu concentrations were compared with known concentrations of Glu in aqueous phantom solutions. Forty‐one patients with known or likely supratentorial gliomas underwent preoperative CSI. The spectra obtained were analyzed for Glu concentrations and Glu to creatine (Cr) ratios. These in vivo measurements were correlated against ex vivo Glu content quantified by high performance liquid chromatography (HPLC) measured in 65 resected brain tumor and peritumoral brain specimens. For the phantom solutions the CSI estimates of Glu concentration and the Glu/Cr ratios were highly correlated with known Glu concentration ( r 2 = 0.95, p = 0.002, and r 2 = 0.97, p < 0.0001, respectively). There was a modest, but statistically significant, correlation between the ex vivo measured Glu and in vivo spectroscopic Glu concentration ( r 2 = 0.22, p = 0.04) and ratios of Glu to Cr ( r 2 = 0.30, p = 0.002). Quantitative measurement of Glu content is feasible in patients with supratentorial gliomas using CSI. The in vitro and in vivo results suggest that this has the potential to be a reliable quantitative imaging assay for brain tumor patients. This may have wide clinical research applications in a number of neurological disorders where Glu excitotoxicity and metabolic dysfunction are known to play a role in pathogenesis, including tumor associated epilepsy, epilepsy, stroke and neurotrauma. Copyright © 2014 John Wiley & Sons, Ltd.