title: Quantification of metabolic differences in the frontal brain of depressive patients and controls obtained by 1H-MRS at 3 Tesla.
abstract: OBJECTIVE
  This study compared metabolic differences in the frontal brain of depressed patients versus age- and sex-matched controls using proton magnetic resonance spectroscopy and absolute quantification of metabolites (NAA, Cr, Cho, mI) at 3 Tesla.
  
  
  METHODS
  Short-echo-time stimulated echo acquisition mode (TE/TM/TR=20/30/6000 milliseconds) was applied in the prefrontal region of 17 depressed patients and 17 age- and sex-matched controls. Metabolic ratios, ie, N-acetyl-aspartate/creatine (Cr), choline/Cr, and myo-inositol/Cr, and absolute concentrations (using internal water as a reference together with LCModel-based spectra fitting) were calculated and compared between groups and published reference data.
  
  
  RESULTS
  Metabolic ratios showed significantly lower N-acetyl-aspartate/Cr (P = 0.016/0.006, left/right), choline/Cr (P = n.s./0.016), and myo-inositol/Cr (P = 0.022/0.026) for depressive patients versus controls. However, depressive patients showed significantly higher absolute concentrations of Cr (P = 0.017/0.0004) compared with controls with no differences in all other metabolites estimated.
  
  
  CONCLUSIONS
  The authors demonstrate that absolute quantification of metabolite concentration is essential in properly identifying pathologic differences of brain metabolites in depression.
authors.affiliation: NMR Group, Department of Medical Physics, University of Vienna, Vienna, Austria.
authors.forename: Stephan
authors.initials: S
authors.lastname: Gruber
authors.forename: Richard
authors.initials: R
authors.lastname: Frey
authors.forename: Vladimir
authors.initials: V
authors.lastname: Mlynárik
authors.forename: Andreas
authors.initials: A
authors.lastname: Stadlbauer
authors.forename: Angela
authors.initials: A
authors.lastname: Heiden
authors.forename: Siegfried
authors.initials: S
authors.lastname: Kasper
authors.forename: Graham J
authors.initials: GJ
authors.lastname: Kemp
authors.forename: Ewald
authors.initials: E
authors.lastname: Moser
mesh_terms: D000328:Adult; D000928:Antidepressive Agents / Q000008:administration & dosage; D001224:Aspartic Acid / Q000031:analogs & derivatives* / Q000378:metabolism; D016022:Case-Control Studies; D002794:Choline / Q000378:metabolism; D003401:Creatine / Q000378:metabolism; D003863:Depression / Q000188:drug therapy / Q000378:metabolism*; D005260:Female; D005625:Frontal Lobe / Q000378:metabolism*; D006801:Humans; D007089:Image Enhancement; D007294:Inositol / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy / Q000295:instrumentation*; D008297:Male
chemical_list: D000928:Antidepressive Agents; D001224:Aspartic Acid; D007294:Inositol; C000179:N-acetylaspartate; D003401:Creatine; D002794:Choline