Estimating glutamate and Glx from GABA-optimized MEGA-PRESS

Off-resonance but not difference spectra values correspond to PRESS values

Research output: Contribution to journalArticle

Abstract

Proton magnetic resonance spectroscopy measurements of glutamate and GABA are important in neuropsychiatric research. Some study designs require simultaneous measurement of both metabolites. GABA measurement requires specialized pulse sequences, the most common approach being J-difference spectral editing with MEGA-PRESS. This method enables two different strategies for concurrently measuring glutamate - from either off-resonance or difference spectra. However, it is uncertain how either strategy compares to conventional glutamate measurements. Here we compared these approaches in 49 subjects (28 healthy volunteers and 21 first-episode psychosis patients), in whom both PRESS (TE 80) and MEGA-PRESS (TE 68) spectra were obtained from dorsolateral prefrontal cortex. Glutamate and glx estimates from MEGA-PRESS difference and off-resonance spectra were compared to glutamate and glx estimates from PRESS spectra using correlational analyses. In healthy volunteers, correlations between PRESS and MEGA-PRESS off-resonance values were r ≥ 0.88 and were significantly higher than correlations between PRESS and MEGA-PRESS difference spectrum values (r ≤ 0.36). Patients showed a similar pattern. Lower correlations with difference spectrum values may reflect a disproportionate impact of field instabilities on co-edited glutamate signals. The results suggest that MEGA-PRESS off-resonance spectra can substitute for separately-acquired PRESS spectra in studies requiring simultaneous glutamate and GABA measurements.

Original languageEnglish (US)
Pages (from-to)22-30
Number of pages9
JournalPsychiatry Research - Neuroimaging
Volume279
DOIs
StatePublished - Sep 30 2018

Fingerprint

gamma-Aminobutyric Acid
Glutamic Acid
Healthy Volunteers
Prefrontal Cortex
Psychotic Disorders
Research

Keywords

  • Brain
  • GABA
  • Glutamate
  • Measurement
  • Metabolites
  • MRS
  • Simultaneous

ASJC Scopus subject areas

  • Neuroscience (miscellaneous)
  • Radiology Nuclear Medicine and imaging
  • Psychiatry and Mental health

Cite this

@article{fd73a29403b642c6a09d7eb8254e2e75,
title = "Estimating glutamate and Glx from GABA-optimized MEGA-PRESS: Off-resonance but not difference spectra values correspond to PRESS values",
abstract = "Proton magnetic resonance spectroscopy measurements of glutamate and GABA are important in neuropsychiatric research. Some study designs require simultaneous measurement of both metabolites. GABA measurement requires specialized pulse sequences, the most common approach being J-difference spectral editing with MEGA-PRESS. This method enables two different strategies for concurrently measuring glutamate - from either off-resonance or difference spectra. However, it is uncertain how either strategy compares to conventional glutamate measurements. Here we compared these approaches in 49 subjects (28 healthy volunteers and 21 first-episode psychosis patients), in whom both PRESS (TE 80) and MEGA-PRESS (TE 68) spectra were obtained from dorsolateral prefrontal cortex. Glutamate and glx estimates from MEGA-PRESS difference and off-resonance spectra were compared to glutamate and glx estimates from PRESS spectra using correlational analyses. In healthy volunteers, correlations between PRESS and MEGA-PRESS off-resonance values were r ≥ 0.88 and were significantly higher than correlations between PRESS and MEGA-PRESS difference spectrum values (r ≤ 0.36). Patients showed a similar pattern. Lower correlations with difference spectrum values may reflect a disproportionate impact of field instabilities on co-edited glutamate signals. The results suggest that MEGA-PRESS off-resonance spectra can substitute for separately-acquired PRESS spectra in studies requiring simultaneous glutamate and GABA measurements.",
keywords = "Brain, GABA, Glutamate, Measurement, Metabolites, MRS, Simultaneous",
author = "Maddock, {Richard J} and Caton, {Michael D.} and Ragland, {John D}",
year = "2018",
month = "9",
day = "30",
doi = "10.1016/j.pscychresns.2018.07.003",
language = "English (US)",
volume = "279",
pages = "22--30",
journal = "Psychiatry Research - Neuroimaging",
issn = "0925-4927",
publisher = "Elsevier Ireland Ltd",

}

TY - JOUR

T1 - Estimating glutamate and Glx from GABA-optimized MEGA-PRESS

T2 - Off-resonance but not difference spectra values correspond to PRESS values

AU - Maddock, Richard J

AU - Caton, Michael D.

AU - Ragland, John D

PY - 2018/9/30

Y1 - 2018/9/30

N2 - Proton magnetic resonance spectroscopy measurements of glutamate and GABA are important in neuropsychiatric research. Some study designs require simultaneous measurement of both metabolites. GABA measurement requires specialized pulse sequences, the most common approach being J-difference spectral editing with MEGA-PRESS. This method enables two different strategies for concurrently measuring glutamate - from either off-resonance or difference spectra. However, it is uncertain how either strategy compares to conventional glutamate measurements. Here we compared these approaches in 49 subjects (28 healthy volunteers and 21 first-episode psychosis patients), in whom both PRESS (TE 80) and MEGA-PRESS (TE 68) spectra were obtained from dorsolateral prefrontal cortex. Glutamate and glx estimates from MEGA-PRESS difference and off-resonance spectra were compared to glutamate and glx estimates from PRESS spectra using correlational analyses. In healthy volunteers, correlations between PRESS and MEGA-PRESS off-resonance values were r ≥ 0.88 and were significantly higher than correlations between PRESS and MEGA-PRESS difference spectrum values (r ≤ 0.36). Patients showed a similar pattern. Lower correlations with difference spectrum values may reflect a disproportionate impact of field instabilities on co-edited glutamate signals. The results suggest that MEGA-PRESS off-resonance spectra can substitute for separately-acquired PRESS spectra in studies requiring simultaneous glutamate and GABA measurements.

AB - Proton magnetic resonance spectroscopy measurements of glutamate and GABA are important in neuropsychiatric research. Some study designs require simultaneous measurement of both metabolites. GABA measurement requires specialized pulse sequences, the most common approach being J-difference spectral editing with MEGA-PRESS. This method enables two different strategies for concurrently measuring glutamate - from either off-resonance or difference spectra. However, it is uncertain how either strategy compares to conventional glutamate measurements. Here we compared these approaches in 49 subjects (28 healthy volunteers and 21 first-episode psychosis patients), in whom both PRESS (TE 80) and MEGA-PRESS (TE 68) spectra were obtained from dorsolateral prefrontal cortex. Glutamate and glx estimates from MEGA-PRESS difference and off-resonance spectra were compared to glutamate and glx estimates from PRESS spectra using correlational analyses. In healthy volunteers, correlations between PRESS and MEGA-PRESS off-resonance values were r ≥ 0.88 and were significantly higher than correlations between PRESS and MEGA-PRESS difference spectrum values (r ≤ 0.36). Patients showed a similar pattern. Lower correlations with difference spectrum values may reflect a disproportionate impact of field instabilities on co-edited glutamate signals. The results suggest that MEGA-PRESS off-resonance spectra can substitute for separately-acquired PRESS spectra in studies requiring simultaneous glutamate and GABA measurements.

KW - Brain

KW - GABA

KW - Glutamate

KW - Measurement

KW - Metabolites

KW - MRS

KW - Simultaneous

UR - http://www.scopus.com/inward/record.url?scp=85050849194&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85050849194&partnerID=8YFLogxK

U2 - 10.1016/j.pscychresns.2018.07.003

DO - 10.1016/j.pscychresns.2018.07.003

M3 - Article

VL - 279

SP - 22

EP - 30

JO - Psychiatry Research - Neuroimaging

JF - Psychiatry Research - Neuroimaging

SN - 0925-4927

ER -