GABA-edited MEGA-PRESS at 3T: Does a measured MM background improve linear combination modeling?

Details

• Alternative Title:
  Magn Reson Med
• Personal Author:
  Davies-Jenkins, Christopher W. ; Zöllner, Helge J. ; Simicic, Dunja ; Hui, Steve C. N. ; Song, Yulu ; Hupfeld, Kathleen E. ; Prisciandaro, James J. ; Edden, Richard A.E. ; Oeltzschner, Georg
• Description:
  Purpose
  
  The J-difference edited GABA signal is contaminated by other co-edited signals—the largest of which originates from co-edited macromolecules (MMs)—and is consequently often reported as “GABA+”. MM signals are broader and less well-characterized than the metabolites, and so are commonly approximated using a Gaussian model parameterization. Experimentally measured MM signals are a consensus-recommended alternative to parameterized modeling; however, they are relatively under-studied in the context of edited MRS.
  
  Methods
  
  To address this limitation in the literature, we have acquired GABA-edited MEGA-PRESS data with pre-inversion to null metabolite signals in 13 healthy controls. An experimental MM basis function was derived from the mean across subjects. We further derived a new parameterization of the MM signals from the experimental data, using multiple Gaussians to accurately represent their observed asymmetry. The previous single-Gaussian parameterization, mean experimental MM spectrum and new multi-Gaussian parameterization were compared in a three-way analysis of a public MEGA-PRESS dataset of 61 healthy participants.
  
  Results
  
  Both the experimental MMs and the multi-Gaussian parameterization exhibited reduced fit residuals compared to the single-Gaussian approach (p = 0.034 & p = 0.031, respectively), suggesting they better represent the underlying data than the single-Gaussian parameterization. Furthermore, both experimentally derived models estimated larger MM fractional contribution to the GABA+ signal for the experimental MMs (58%) and multi-Gaussian parameterization (58%), compared to the single-Gaussian approach (50%).
  
  Conclusions
  
  Our results indicate that single-Gaussian parameterization of edited MM signals is insufficient and that both experimentally derived GABA+ spectra and their parameterized replicas improve the modeling of GABA+ spectra.
  
  
• Subjects:
  Adult Algorithms Brain Female Gamma-Aminobutyric Acid Humans Linear Models Macromolecular Substances Magnetic Resonance Spectroscopy Male Normal Distribution Young Adult

  More +
• Keywords:
  GABA GABA+ Macromolecules MEGA-PRESS Metabolite-nulled
• Source:
  Magn Reson Med. 92(4):1348-1362
• Pubmed ID:
  38818623
• Pubmed Central ID:
  PMC11262975
• Document Type:
  Journal Article
• Funding:
  P41 EB031771/EB/NIBIB NIH HHSUnited States/ ; R00 AG062230/AG/NIA NIH HHSUnited States/ ; R01 EB023963/EB/NIBIB NIH HHSUnited States/ ; R21 EB033516/EB/NIBIB NIH HHSUnited States/ ; S10 OD021648/OD/NIH HHSUnited States/ ; R01 EB016089/EB/NIBIB NIH HHSUnited States/ ; K99 AG080084/AG/NIA NIH HHSUnited States/ ; S10 OD021648/CD/ODCDC CDC HHSUnited States/
• Volume:
  92
• Issue:
  4
• Collection(s):
  CDC Public Access
• Main Document Checksum:
  urn:sha-512:086167d4858f71f2155659edb72cd75f5b0e405173dc6e065897329284c3a1a62b5db403ec04b40da8e83df47b93b9e1c2acf5613259bf97617dd09a748d32fb
• Download URL:
  https://stacks.cdc.gov/view/cdc/159345/cdc_159345_DS1.pdf
• File Type:
  [PDF - 1020.85 KB ]