TY - JOUR
T1 - Glutamate quantification by PRESS or MEGA-PRESS
T2 - Validation, repeatability, and concordance
AU - van Veenendaal, Tamar M.
AU - Backes, Walter H.
AU - van Bussel, Frank C. G.
AU - Edden, Richard A. E.
AU - Puts, Nicolaas A. J.
AU - Aldenkamp, Albert P.
AU - Jansen, Jacobus F. A.
PY - 2018/5/1
Y1 - 2018/5/1
N2 - Purpose: While PRESS is often employed to measure glutamate concentrations, MEGA-PRESS enables simultaneous Glx (glutamate and glutamine) and GABA measurements. This study aimed to compare validation, repeatability, and concordance of different approaches for glutamate quantification at 3 T to aid future studies in their selection of the appropriate sequence and quantification method. Materials and methods: Nine phantoms with different glutamate and glutamine concentrations and five healthy participants were scanned twice to assess respectively the validation and repeatability of measurements with PRESS and MEGA-PRESS. To assess concordance between the different methods, results from 95 human participants were compared. PRESS, MEGA-PRESS (i.e. difference), and the MEGA-PRESS OFF spectra were analyzed with both LCModel and Gannet. Results: In vitro, excellent agreement was shown between actual and measured glutamate concentrations for all measurements (r > 0.98). In vivo CVs were better for PRESS (2.9%) than MEGA-PRESS (4.9%) and MEGA PRESS OFF (4.2%). However, the concordance between the sequences was low (PRESS and MEGA-PRESS OFF, r = 0.3) to modest (MEGA-PRESS versus MEGA-PRESS OFF, r = 0.8). Conclusion: Both PRESS and MEGA-PRESS can be employed to measure in vivo glutamate concentrations, although PRESS shows a better repeatability. Comparisons between in vivo glutamate measures of different sequences however need to be interpreted cautiously.
AB - Purpose: While PRESS is often employed to measure glutamate concentrations, MEGA-PRESS enables simultaneous Glx (glutamate and glutamine) and GABA measurements. This study aimed to compare validation, repeatability, and concordance of different approaches for glutamate quantification at 3 T to aid future studies in their selection of the appropriate sequence and quantification method. Materials and methods: Nine phantoms with different glutamate and glutamine concentrations and five healthy participants were scanned twice to assess respectively the validation and repeatability of measurements with PRESS and MEGA-PRESS. To assess concordance between the different methods, results from 95 human participants were compared. PRESS, MEGA-PRESS (i.e. difference), and the MEGA-PRESS OFF spectra were analyzed with both LCModel and Gannet. Results: In vitro, excellent agreement was shown between actual and measured glutamate concentrations for all measurements (r > 0.98). In vivo CVs were better for PRESS (2.9%) than MEGA-PRESS (4.9%) and MEGA PRESS OFF (4.2%). However, the concordance between the sequences was low (PRESS and MEGA-PRESS OFF, r = 0.3) to modest (MEGA-PRESS versus MEGA-PRESS OFF, r = 0.8). Conclusion: Both PRESS and MEGA-PRESS can be employed to measure in vivo glutamate concentrations, although PRESS shows a better repeatability. Comparisons between in vivo glutamate measures of different sequences however need to be interpreted cautiously.
KW - Glutamate
KW - Glx
KW - MR spectroscopy
KW - In vitro
KW - In vivo
KW - MAGNETIC-RESONANCE-SPECTROSCOPY
KW - GAMMA-AMINOBUTYRIC-ACID
KW - IN-VIVO DETECTION
KW - HUMAN BRAIN
KW - MR SPECTROSCOPY
KW - H-1-NMR SPECTROSCOPY
KW - 3 TESLA
KW - GABA
KW - METABOLITES
KW - SPECTRA
U2 - 10.1016/j.mri.2017.12.029
DO - 10.1016/j.mri.2017.12.029
M3 - Article
C2 - 29306050
SN - 0730-725X
VL - 48
SP - 107
EP - 114
JO - Magnetic Resonance Imaging
JF - Magnetic Resonance Imaging
ER -