Simultaneous editing of GABA and glutathione at 7T using semi-LASER localization

Muhammad G. Saleh, Mark Mikkelsen, Georg Oeltzschner, Kimberly L. Chan, Adam Berrington, Peter B Barker, Richard Anthony Edward Edden

Research output: Contribution to journalArticle

Abstract

Purpose: To demonstrate simultaneous editing of the two most commonly edited and overlapping signals, γ-aminobutyric acid (GABA), and glutathione (GSH), with Hadamard encoding and reconstruction of MEGA-edited spectroscopy (HERMES) using sLASER localization at 7T. Methods: Density matrix simulations of HERMES at 7T were carried out and compared with phantom experiments. Additional phantom experiments were performed to characterize the echo time (TE) -dependent modulation of GABA- and GSH-edited HERMES spectra at TE of 80-160 ms. In vivo experiments were performed in 10 healthy volunteers, comparing HERMES (11min) to sequentially acquired MEGA-sLASER detection of GABA and GSH (2×11min). Results: Simulations of HERMES show GABA- and GSH-edited spectra with negligible levels of crosstalk, and give modest agreement with phantom spectra. The TE series of GABA- and GSH-edited HERMES spectra modulate as a result of T2 relaxation and coupling evolution, with GABA showing a stronger TE-dependence. In vivo HERMES experiments show well-edited GABA and GSH signals. Measured concentrations are not statistically different between HERMES and MEGA-sLASER for GABA (1. 051±0.254 i.u. and 1.053±0.248 i.u; P>0.985) or GSH (0.300±0.091 i.u. and 0.302±0.093 i.u; P>0.940). Conclusion: Simulated, phantom and in vivo measurements of HERMES show excellent segregation of GABA- and GSH-edited signals, and excellent agreement with separately acquired MEGA-sLASER data. HERMES allows two-fold acceleration of editing while maintaining spectral quality compared with sequentially acquired MEGA-sLASER measurements.

Original languageEnglish (US)
JournalMagnetic Resonance in Medicine
DOIs
StateAccepted/In press - Jan 1 2018

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Keywords

  • 7T
  • Editing
  • GABA
  • GSH
  • HERMES
  • Semi-LASER

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging

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