title: Effect of J-coupling on lipid composition determination with localized proton magnetic resonance spectroscopy at 9.4 T.
abstract: OBJECTIVE
  To demonstrate, at 9.4 T, that J-coupling interactions exhibited by lipid protons affects lipid composition determination with a point resolved spectroscopy (PRESS) sequence.
  
  
  METHODS
  Experiments were conducted on four oils (almond, corn, sesame, and sunflower), on visceral adipose tissue of a euthanized mouse, and on pure linoleic acid at 9.4 T. The 2.1, 2.3, and 2.8 ppm resonances were measured at multiple echo times (TEs) by a standard PRESS sequence and by a PRESS sequence consisting of narrow-bandwidth refocusing pulses designed to rewind the J-coupling evolution of the target peak protons in the voxel of interest. T(2) corrections were performed on both groups of data for the three peaks and lipid compositions for the oils and for the mouse tissue were determined. Lipid compositions were also calculated from a short-TE standard PRESS spectrum.
  
  
  RESULTS
  A chemical analysis of the samples was not performed; however, the oil compositions calculated from resonance peaks acquired with the PRESS sequence designed to minimize J-coupling effects, following T(2) relaxation correction, closely agreed with values in the literature, which was not the case for all of the compositions determined from the regular PRESS spectra.
  
  
  CONCLUSIONS
  The presented work brings to attention the significance of J-coupling effects when calculating lipid compositions from localized proton spectra.
authors.affiliation: Department of Medical Physics, Cross Cancer Institute, Edmonton, Alberta, Canada; Department of Oncology, University of Alberta, Edmonton, Alberta, Canada. ayahya@ualberta.ca
authors.forename: Atiyah
authors.initials: A
authors.lastname: Yahya
authors.forename: Anthony G
authors.initials: AG
authors.lastname: Tessier
authors.forename: B Gino
authors.initials: BG
authors.lastname: Fallone
mesh_terms: D000273:Adipose Tissue / Q000737:chemistry*; D000818:Animals; D019787:Linoleic Acid / Q000032:analysis; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D051379:Mice; D009821:Oils / Q000032:analysis*; D014781:Viscera
chemical_list: D009821:Oils; D019787:Linoleic Acid