title: Detection of cerebral metabolites by single-voxel-based PRESS and COSY techniques at 3T.
abstract: OBJECTIVE
  To compare point-resolved spectroscopy (PRESS) and localized two-dimensional (2D) correlated spectroscopy (L-COSY) in the detection of cerebral metabolites in humans on a clinical scanner at 3T and to estimate their respective inter- and intrasubject variances.
  
  
  METHODS
  Measurements were made on nine healthy subjects to assess intersubject variance, and daily on a single subject over a period of seven days to assess intrasubject variance. All L-COSY measurements were performed with a voxel size of 27 mL (3 x 3 x 3 cm(3)) and a measurement time of approximately 34 minutes in the occipitoparietal lobe of the brain. Relative metabolite concentrations were estimated with respect to N-methyl creatine.
  
  
  RESULTS
  While the sensitivity of PRESS is twice that of L-COSY, the greater spectral resolution offered by L-COSY resulted in greater consistency in estimates of the concentrations of several cerebral metabolites, as indicated by a superior intraclass correlation and a significantly lower standard deviation (SD) in a matched pair intrasubject analysis.
  
  
  CONCLUSIONS
  Our pilot results demonstrate that L-COSY is an effective approach for resolving cerebral metabolites, and demonstrates a lower coefficient of variance (CV) than the conventional 1D localized spectroscopic approach using LC Model for quantification.
authors.affiliation: Center for Advanced Imaging and Radiology, West Virginia University, Morgantown, West Virginia 26506, USA. svelan@hsc.wvu.edu
authors.forename: S Sendhil
authors.initials: SS
authors.lastname: Velan
authors.forename: Susan K
authors.initials: SK
authors.lastname: Lemieux
authors.forename: Raymond R
authors.initials: RR
authors.lastname: Raylman
authors.forename: Warren
authors.initials: W
authors.lastname: Boling
authors.forename: Gerald R
authors.initials: GR
authors.lastname: Hobbs
authors.forename: Richard G
authors.initials: RG
authors.lastname: Spencer
authors.forename: Rajagopalan
authors.initials: R
authors.lastname: Sridhar
authors.forename: Periannan
authors.initials: P
authors.lastname: Kuppusamy
authors.forename: M Albert
authors.initials: MA
authors.lastname: Thomas
mesh_terms: D000328:Adult; D000465:Algorithms; D001921:Brain / Q000378:metabolism* / Q000473:pathology; D001931:Brain Mapping / Q000379:methods; D006801:Humans; D007091:Image Processing, Computer-Assisted; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008280:Magnetics; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013053:Spectrophotometry / Q000379:methods