Impact of frequency drift on gamma-aminobutyric acid-edited MR spectroscopy

Purpose: To investigate the quantitative impact of frequency drift on Gamma-Aminobutyric acid (GABA+)-edited MRS of the human brain at 3 Tesla (T). Methods: Three sequential GABA+-edited MEGA-PRESS acquisitions were acquired in fifteen sessions; in ten of these, MRS was preceded by functional MRI (fMRI) to induce frequency drift, which was estimated from the creatine resonance at 3.0 ppm. Simulations were performed to examine the effects of frequency drift on the editing efficiency of GABA and co-edited macromolecules (MM) and of subtraction artifacts on GABA+ quantification. The efficacy of postprocessing frequency correction was also investigated. Results: Gradient-induced frequency drifts affect GABA+ quantification for at least 30 min after imaging. Average frequency drift was low in control sessions and as high as −2 Hz/min after fMRI. Uncorrected frequency drift has an approximately linear effect on GABA+ measurements with a −10 Hz drift resulting in a 16% decrease in GABA+, primarily due to subtraction artifacts. Conclusion: Imaging acquisitions with high gradient duty cycles can impact subsequent GABA+ measurements. Postprocessing can address subtraction artifacts, but not changes in editing efficiency or GABA:MM signal ratios; therefore, protocol design should avoid intensive gradient sequences before edited MRS Magn Reson Med 72:941–948, 2014

Current practice in the use of MEGA-PRESS spectroscopy for the detection of GABA

There is increasing interest in the use of edited proton magnetic resonance spectroscopy for the detection of GABA in the human brain. At a recent meeting held at Cardiff University, a number of spectroscopy groups met to discuss the acquisition, analysis and interpretation of GABA-edited MR spectra. This paper aims to set out the issues discussed at this meeting, reporting areas of consensus around parameters and procedures in the field and highlighting those areas where differences remain. It is hoped that this paper can fulfill two needs, providing a summary of the current 'state-of-the-art' in the field of GABA-edited MRS at 3T using MEGA-PRESS and a basic guide to help researchers new to the field to avoid some of the pitfalls inherent in the acquisition and processing of edited MRS for GABA

ACC GABA levels are associated with functional activation and connectivity in the fronto-striatal network during interference inhibition in patients with borderline personality disorder

FSW - Self-regulation models for health behavior and psychopathology - ou