Improved prospective frequency correction for macromolecule-suppressed GABA editing with metabolite cycling at 3T.

Autor: Chan KL; Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA., Hock A; MR Clinical Science, Philips Health Systems, Horgen, Switzerland., Edden RAE; Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.; F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA., MacMillan EL; UBC MRI Research Centre, University of British Columbia, Vancouver, British Columbia, Canada.; SFU ImageTech Lab, Simon Fraser University, Surrey, British Columbia, Canada.; MR Clinical Science, Philips Healthcare, Markham, Ontario, Canada., Henning A; Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA.; Max Planck Institute for Biological Cybernetics, Tübingen, Germany.
Jazyk: angličtina
Zdroj: Magnetic resonance in medicine [Magn Reson Med] 2021 Dec; Vol. 86 (6), pp. 2945-2956. Date of Electronic Publication: 2021 Aug 25.
DOI: 10.1002/mrm.28950
Abstrakt: Purpose: To combine metabolite cycling with J-difference editing (MC MEGA) to allow for prospective frequency correction at each transient without additional acquisitions and compare it to water-suppressed MEGA-PRESS (WS MEGA) editing with intermittent prospective frequency correction.
Methods: Macromolecule-suppressed gamma aminobutyric acid (GABA)-edited experiments were performed in a phantom and in the occipital lobe (OCC) (n = 12) and medial prefrontal cortex (mPFC) (n = 8) of the human brain. Water frequency consistency and average offset over acquisition time were compared. GABA multiplet patterns, signal intensities, and choline subtraction artifacts were evaluated. In vivo GABA concentrations were compared and related to frequency offset in the OCC.
Results: MC MEGA was more stable with 21% and 32% smaller water frequency SDs in the OCC and mPFC, respectively. MC MEGA also had 39% and 40% smaller average frequency offsets in the OCC and mPFC, respectively. Phantom GABA multiplet patterns and signal intensities were similar. In vivo GABA concentrations were smaller in MC MEGA than in WS MEGA, with median (interquartile range) of 2.52 (0.27) and 2.29 (0.19) institutional units (i.u.), respectively in the OCC scans without prior DTI, and 0.99 (0.3) and 1.72 (0.5), respectively in the mPFC. OCC WS MEGA GABA concentrations, but not MC MEGA GABA concentrations were moderately correlated with frequency offset. mPFC WS MEGA spectra contained significantly more subtraction artifacts than MC MEGA spectra.
Conclusion: MC MEGA is feasible and allows for prospective frequency correction at every transient. MC MEGA GABA concentrations were not biased by frequency offsets and contained less subtraction artifacts compared to WS MEGA.
(© 2021 International Society for Magnetic Resonance in Medicine.)
Databáze: MEDLINE
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