Reliability of Glutamate Quantification in Human Nucleus Accumbens Using Proton Magnetic Resonance Spectroscopy at a 70-cm Wide-Bore Clinical 3T MRI System

Abstract

The human nucleus accumbens is a challenging region to study using proton magnetic resonance spectroscopy (1H-MRS) on a 70-cm wide-bore clinical 3T MRI system. The aim of this study was to investigate the reliability for quantitative measurement of glutamate concentration in the nucleus accumbens using a 70-cm wide-bore clinical 3T MRI. 1H-MRS of the nucleus accumbens was acquired using the Point-Resolved Spectroscopic Sequence (PRESS) with echo time of 40 ms from 10 healthy volunteers (5 female; age range: 18–30 years) on two separate visits (a baseline, and 1-month time point). The Java-based Magnetic Resonance User Interface (jMRUI) software package was used to quantitatively measure the absolute metabolite concentrations. The test-retest reliability and reproducibility were assessed using intraclass correlations coefficients (ICC), and coefficients of variation (CV). Glutamate concentrations were similar across visits (P = 0.832). Reproducibility measures for all metabolites were good with CV ranging from 7.8 to 14.0%. The ICC values of all metabolites for the intra-class measures were excellent (ICC > 0.8), except that the reliability for Glx (glutamate + glutamine) was good (ICC = 0.768). Pearson correlations for all metabolites were all highly significant (r = 0.636–0.788, P < 0.05). In conclusion, the short-echo-time PRESS can reliably obtain high quality glutamate spectrum from a ~3.4 cm3 voxel of the nucleus accumbens using a 70-cm wide-bore clinical 3T MRI.

Test–Retest Reliability of the Brain Metabolites GABA and Glx With JPRESS, PRESS, and MEGA‐PRESS MRS Sequences in vivo at 3T

“…The highest precision is exhibited by PRESS for Glx, Glu, and Gln. In addition, the r correlation coefficients confirm the high precision achieved by PRESS for Glx (0.87) and Glu (0.77), which are comparable to, or slightly better than, values reported in the literature (0.64 and 0.79, respectively), although the latter values were obtained with a smaller voxel size (3.4 mL). Indeed, PRESS is a conventional and reliable sequence with a favorably short acquisition time, as indicated by our results and previous works.…”

“…36 Some ICC analyses were already reported. 15,17,18 Only two previous studies 15,17 applied the Pearson's r correlation method to measure the reliability of GABA detection by MEGA-PRESS and one 19 to measure the reliability of Glx detection by PRESS. Moreover, only two investigations, 20,21 one using semi-LASER (Localized by Adiabatic SElective Refocusing) and another using 2D L-COSY (Localized COrrelational Spectros-copY) sequences at 3T and 7T, reported on the PCC region of the brain, despite its important function in brain regulation and homeostasis and its extensive implication in several neurodegenerative processes.…”

“…Almost all previous works reported coefficient of variation (CV) values only, and few studies compared intraclass correlation coefficients (ICC), using mainly the MEGA‐PRESS sequence. Three papers discussed Pearson's correlations and only van Veenendaal et al reported Bland–Altman (BA) plots. So far, two brain regions have been extensively examined: the anterior cingulate cortex (ACC) and the occipital lobe (OL).…”

“…8,9 Most of the previously published studies investigating the reliability of MRS methods have focused on characterizing the test-retest reproducibility of GABA concentrations derived with MEGA-PRESS. [10][11][12][13][14][15][16][17][18] Almost all previous works reported coefficient of variation (CV) values only, and few studies compared intraclass correlation coefficients (ICC), 15,[17][18][19] using mainly the MEGA-PRESS sequence. Three papers 15,17,19 discussed Pearson's correlations and only van Veenendaal et al 10 reported Bland-Altman (BA) plots.…”

Prefrontal GABA and glutamate levels correlate with impulsivity and cognitive function of prescription opioid addicts: A 1H‐magnetic resonance spectroscopy study

“…As there is no established method to dissociate pooled and neurotransmitter glutamate so far, more advanced spectral scanning methods should be developed to better separate the two. Moreover, although many researchers believe that the glutamate detected by PRESS sequence has a good reliability and reproducibility, it is still a cause for concern whether glutamate can be completely differentiated from glutamine in a 3.0‐T magnetic field. Finally, we did not account for the macromolecule signals that co‐edited with the 3.01 p.p.m.…”