title: Short echo time 1H MRSI of the human brain at 3T with adiabatic slice-selective refocusing pulses; reproducibility and variance in a dual center setting.
abstract: OBJECTIVE
  To assess the reproducibility of (1)H-MR spectroscopic imaging (MRSI) of the human brain at 3T with volume selection by a double spin echo sequence for localization with adiabatic refocusing pulses (semi-LASER).
  
  
  METHODS
  Twenty volunteers in two different institutions were measured twice with the same pulse sequence at an echo time of 30 msec. Magnetic resonance (MR) spectra were analyzed with LCModel with a simulated basis set including an experimentally acquired macromolecular signal profile. For specific regions in the brain mean metabolite levels, within and between subject variance, and the coefficient of variation (CoV) were calculated (for taurine, glutamate, total N-acetylaspartate, total creatine, total choline, myo-inositol + glycine, and glutamate + glutamine).
  
  
  RESULTS
  Repeated measurements showed no significant differences with a paired t-test and a high reproducibility (CoV ranging from 3%-30% throughout the selected volume). Mean metabolite levels and CoV obtained in similar regions in the brain did not differ significantly between two contributing institutions. The major source of differences between different measurements was identified to be the between-subject variations in the volunteers.
  
  
  CONCLUSIONS
  We conclude that semi-LASER (1)H-MRSI at 3T is an adequate method to obtain quantitative and reproducible measures of metabolite levels over large parts of the brain, applicable across multiple centers.
authors.affiliation: Department of Radiology, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands. j.wijnen@rad.umcn.nl
authors.forename: Jannie P
authors.initials: JP
authors.lastname: Wijnen
authors.forename: Jack J A
authors.initials: JJ
authors.lastname: van Asten
authors.forename: Dennis W J
authors.initials: DW
authors.lastname: Klomp
authors.forename: Torill E
authors.initials: TE
authors.lastname: Sjobakk
authors.forename: Ingrid S
authors.initials: IS
authors.lastname: Gribbestad
authors.forename: Tom W J
authors.initials: TW
authors.lastname: Scheenen
authors.forename: Arend
authors.initials: A
authors.lastname: Heerschap
mesh_terms: D000465:Algorithms; D015415:Biomarkers / Q000032:analysis*; D001921:Brain / Q000378:metabolism*; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D011522:Protons; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014018:Tissue Distribution; D055815:Young Adult
chemical_list: D015415:Biomarkers; D011522:Protons