A 3T MRS Sequence for Quantification of Glutathione in Human Brain Using Stepwise Filtering

In vivo quantification of brain glutathione (GSH) is severely confounded by extreme spectral overlap in conventional ¹H MRS. We developed a novel StepWIse FilTering Point-Resolved Spectroscopy (SWIFT-PRESS) sequence to fundamentally address this inherent limitation.

Transposing the stepwise filtering strategy from classical signal processing into quantum spin dynamics, SWIFT-PRESS concatenates multiple customized filter modules. This cascaded architecture circumvents the inherent inability of single-pass filters to simultaneously preserve target signals and completely eradicate interference. The proposed sequence was rigorously benchmarked against conventional PRESS and MEGA-PRESS.

Simulations and phantom validations demonstrated that SWIFT-PRESS successfully eradicated the dominant creatine-derived interference while maintaining a highly acceptable GSH retention yield of ˜70%. In vivo human brain acquisitions confirmed its exceptional selectivity and robustness in both the parietal lobe and the magnetically complex basal ganglia, yielding precise mean GSH concentrations of 2.45 mM and 2.88 mM, respectively. Crucially, SWIFT-PRESS uncovered a pronounced inhomogeneous GSH distribution within the basal ganglia, directly reflecting underlying micro-regional metabolic heterogeneity.

Transcending the limitations of conventional spectral editing, SWIFT-PRESS enables the highly specific, stable, and quantitative in vivo detection of brain GSH. By illuminating previously obscured spatial metabolic nuances, this technique establishes a robust methodological foundation for advanced clinical investigations of oxidative stress-related disorders.