title: Absolute quantitation of brain 1H nuclear magnetic resonance spectra. Comparison of different approaches.
abstract: OBJECTIVE
  Three different calibration techniques of 1H localized nuclear magnetic resonance (NMR) spectra were applied to a group of healthy volunteers. Absolute concentrations of the metabolites and their standard deviations were compared, and the clinical feasibility of these calibration technique is discussed.
  
  
  METHODS
  Eighteen healthy volunteers were included in the study. Both water and creatine were used as internal standard, and a pertinent solution of metabolites was used as an external standard. The T2 relaxation times of the brain metabolites were evaluated in each examination.
  
  
  CONCLUSIONS
  The concentrations obtained using water as an internal standard and using an external standard are very similar, and the first of these methods show smaller standard deviations. The authors' results show that the use of creatine as an internal standard may induce systematic errors in absolute calibration because of the uncertainty on the true creatine concentration.
authors.affiliation: Dipartimento di Fisica, Università di Trieste, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Longo
authors.forename: A
authors.initials: A
authors.lastname: Bampo
authors.forename: R
authors.initials: R
authors.lastname: Vidimari
authors.forename: S
authors.initials: S
authors.lastname: Magnaldi
authors.forename: A
authors.initials: A
authors.lastname: Giorgini
mesh_terms: D000328:Adult; D000368:Aged; D001224:Aspartic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D001834:Body Water / Q000378:metabolism; D001921:Brain / Q000378:metabolism*; D001923:Brain Chemistry; D002138:Calibration; D002794:Choline / Q000378:metabolism; D003401:Creatine / Q000378:metabolism; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008297:Male
chemical_list: D001224:Aspartic Acid; C000179:N-acetylaspartate; D003401:Creatine; D002794:Choline