Prospective frequency and motion correction for edited ¹H magnetic resonance spectroscopy

Area of Science:

• Neuroscience
• Medical Imaging
• Biochemistry

Background:

• Gamma-aminobutyric acid (GABA) and glutathione (GSH) are vital brain neurometabolites implicated in neurological and psychiatric disorders.
• Magnetic resonance spectroscopy (MRS) non-invasively measures these metabolites but is highly sensitive to head motion, particularly in patient populations.
• Spectral editing techniques (e.g., HERMES) enhance GABA and GSH detection but increase motion sensitivity due to longer echo times and selective pulses.

Purpose of the Study:

• To investigate and correct motion sensitivity in conventional short-TE MRS (PRESS) and edited MRS (HERMES).
• To evaluate the efficacy of a navigator-based prospective motion correction strategy combined with retrospective outlier removal.

Main Methods:

• Implementation of a navigator-based prospective motion correction strategy with data reacquisition.
• Acquisition of PRESS and HERMES spectra under no-motion, motion-with-correction, and motion-without-correction conditions.
• Comparison of spectral quality and metabolite quantification across different motion and correction scenarios.

Main Results:

• Retrospective outlier removal alone was insufficient for edited MRS (HERMES), showing significant differences in metabolite estimates (tCr, GABA+, GSH) and spectral quality variability.
• Prospective motion correction, when combined with retrospective methods, significantly improved spectral quality in both PRESS and HERMES, approaching no-motion acquisition levels.
• No significant differences in GABA and GSH metabolite ratios were observed when motion correction was applied.

Conclusions:

• Edited MRS (HERMES) is more susceptible to motion artifacts compared to conventional MRS (PRESS).
• Prospective motion correction is effective in restoring spectral quality for both conventional and edited MRS, mitigating motion-induced artifacts.
• The combined prospective and retrospective correction strategy enhances the reliability of neurometabolite quantification in MRS studies.