Assessment of the Precision in Measuring Glutathione at 3 T With a MEGA-PRESS Sequence in Primary Motor Cortex and Occipital Cortex

Background: Glutathione (GSH) is an important brain antioxidant and a number of studies have reported its measurement by edited and nonedited localized ¹ H spectroscopy techniques within a range of applications in healthy volunteers and disease states. Good test-retest reproducibility is key when assessing the efficacy of treatments aimed at modulating GSH levels within the central nervous system or when noninvasively assessing changes in GSH content over time.

Purpose: To evaluate the intraday (in vitro and in vivo) and 1-month apart (in vivo) test-retest reproducibility of GSH measurements from GSH-edited MEGA-PRESS acquisitions at 3 T in a phantom and in the brain of a cohort of middle-aged and older healthy volunteers.

Study type: Prospective.

Subjects/phantoms: A phantom containing physiological concentrations of GSH and metabolites with overlapping spectral signatures and 10 healthy volunteers (4 F, 6 M, 55 ± 14 years old).

Field strength/sequence: GSH-edited spectra were acquired at 3 T using the MEGA-PRESS sequence.

Assessment: The phantom was scanned twice and the healthy subjects were scanned three times (on two separate days, 1 month apart). GSH was quantified from each acquisition, with the in vivo voxels placed at the primary motor cortex (PMC) and the occipital cortex (OCC).

Statistical tests: Mean coefficients of variation (CV) were used to assess short-term (in vitro and in vivo) and longer-term (in vivo) test-retest reproducibility.

Results: In vitro, the CV was 2.3%. In vivo, the mean intraday CV was 3.3% in the PMC and 2.4% in the OCC, while the CVs at 1 month apart were 4.6% in the PMC and 7.8% in the OCC.

Data conclusion: GSH-edited MEGA-PRESS spectroscopy allows measurement of GSH with excellent precision.

Evidence level: 1 TECHNICAL EFFICACY: Stage 2.