Measurement of glutathione in normal volunteers and stroke patients at 3T using J-difference spectroscopy with minimized subtraction errors

Purpose: To develop and optimize a ¹H magnetic resonance spectroscopy (MRS) method for measuring brain glutathione (GSH) levels. Materials and Methods: Phantom experiments and density operator simulations were performed to determine the optimal TE for measuring GSH at 3T using J-difference spectral editing. In vivo data collected from 11 normal volunteers (43 measurements) and five stroke patients (10 measurements) were processed using a new spectral alignment method (adaptive spectral registration). Results: In phantom experiments and density operator simulations where relaxation effects were ignored, close to maximum GSH signal (2.95 ppm) was obtained at TE ≈ 131 msec with minimum N-acetyl-aspartate (NAA) signal interference. Using adaptive spectral registration, GSH levels in healthy volunteers were found to be 1.20 ± 0.14 mM (mean ± standard deviation [SD]). GSH levels in stroke patients were found to be 1.19 ± 0.24 mM in lesion and 1.25 ± 0.19 mM in contralateral normal tissue. In comparison, the SDs were significantly larger when only the NAA singlet (2.01 ppm) was used as a navigator for spectral alignment. Conclusion: Spectral editing using J-differences is a reliable method for measuring GSH levels in volunteers and stroke patients.