title: Two-dimensional J-resolved LASER and semi-LASER spectroscopy of human brain.
abstract: OBJECTIVE
  Two-dimensional J-resolved localized and semi-localized by adiabatic selective refocusing (LASER and semi-LASER) spectroscopy, named "J-resolved LASER" and "J-resolved semi-LASER", were introduced to suppress chemical shift artifacts, additional J-refocused artifactual peaks from spatially dependent J-coupling evolution, and sensitivity to radiofrequency (RF) field inhomogeneity.
  
  
  METHODS
  Three pairs of adiabatic pulses were employed for voxel localization in J-resolved LASER and two pairs in J-resolved semi-LASER. The first half of t1 period was inserted between the last pair of adiabatic pulses, which was proposed in this work to obtain two-dimensional adiabatic J-resolved spectra of human brain for the first time. Phantom and human experiments were performed to demonstrate their feasibility and advantages over conventional J-resolved spectroscopy (JPRESS).
  
  
  RESULTS
  Compared to JPRESS, J-resolved LASER or J-resolved semi-LASER exhibited significant suppression of chemical shift artifacts and additional J-refocused peaks from spatially dependent J-coupling evolution, and demonstrated insensitivity to the change of RF frequency offset over large bandwidth.
  
  
  CONCLUSIONS
  Experiments on phantoms and human brains verified the feasibility and strengths of two-dimensional adiabatic J-resolved spectroscopy at 3T. This technique is expected to advance the application of in vivo two-dimensional MR spectroscopy at 3T and higher field strengths for more reliable and accurate quantification of metabolites.
authors.affiliation: Department of Psychiatry, University of Illinois at Chicago, Chicago, Illinois, USA.
authors.forename: Meijin
authors.initials: M
authors.lastname: Lin
authors.forename: Anand
authors.initials: A
authors.lastname: Kumar
authors.forename: Shaolin
authors.initials: S
authors.lastname: Yang
mesh_terms: D000465:Algorithms; D016477:Artifacts; D001921:Brain; D001923:Brain Chemistry; D006801:Humans; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*