Echo time optimization for J-difference editing of glutathione at 3T

Kimberly L. Chan, Nicolaas Puts, Karim Snoussi, Ashley D. Harris, Peter B Barker, Richard Anthony Edward Edden

Research output: Contribution to journalArticle

Abstract

Purpose: To investigate the echo time (TE) dependence of J-difference editing of glutathione and to determine the optimal TE for in vivo measurements at 3T. Methods: Spatially resolved density-matrix simulations and phantom experiments were performed at a range of TEs to establish the spatial and TE modulation of glutathione signals in editing-on, editing-off, and difference spectra at 3T. In vivo data were acquired in five healthy subjects to compare a TE of 68 ms and a TE of 120 ms. At the longer TE, high-bandwidth, frequency-modulated, slice-selective refocusing pulses were also compared with conventional amplitude-modulated pulses. Results: Simulations and relaxation-corrected phantom experiments suggest that the maximum edited signal occurs at TE 160 ms, ignoring transverse relaxation. Considering in vivo T2 relaxation times of 67-89 ms, the optimal in vivo TE is estimated to be 120 ms. In vivo measurements showed that this TE yielded 15% more signal than TE 68 ms. A further gain of 57% resulted from using improved slice-selective refocusing pulses. Conclusion: J-difference editing of glutathione using TE 120 ms delivers increased signal due to improved editing efficiency that more than offsets T2 losses. The additional TE also allows for use of improved slice-selective refocusing pulses, which results in additional signal gains.

Original languageEnglish (US)
JournalMagnetic Resonance in Medicine
DOIs
StateAccepted/In press - 2016

    Fingerprint

Keywords

  • Brain
  • Echo time
  • Edited MRS
  • Glutathione
  • GSH

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging

Cite this