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

Ashley D. Harris, Benjamin Glaubitz, Jamie Near, C. John Evans, Nicolaas A.J. Puts, Tobias Schmidt-Wilcke, Martin Tegenthoff, Peter B. Barker, Richard A.E. Edden

Research output: Contribution to journalArticle

Abstract

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.

Original languageEnglish (US)
Pages (from-to)941-948
Number of pages8
JournalMagnetic resonance in medicine
Volume72
Issue number4
DOIs
StatePublished - Jan 1 2014

Keywords

  • Edited MRS
  • Editing efficiency
  • Frequency drift
  • GABA
  • Subtraction artifact

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging

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