title: Quantitative metabolite patterns of human brain tumors: detection by 1H NMR spectroscopy in vivo and in vitro.
abstract: OBJECTIVE
  The aim of the present study was to investigate quantitative metabolite patterns in human brain tumors by 1H nuclear MR spectroscopy (1H MRS).
  
  
  METHODS
  Single voxel 1H MRS was used in studying metabolites in 23 primary brain tumors in vivo. The T2 relaxation times and saturation factors were determined for N-acetylaspartate (NAA), total creatine (Cr), choline-containing compounds (Cho), and water, which was used as an internal standard in computations of metabolite concentrations in vivo. Metabolites in biopsy specimens from 75 tumors were quantified by means of 1H MRS in vitro.
  
  
  RESULTS
  The NAA concentrations were lower in brain tumors than in normal tissue in vitro and in vivo, irrespective of the histological type. The NAA was some threefold higher in vivo than in vitro, which could be due to partial volume effect and/or contributions from other metabolites to the peak at 2.02 ppm in vivo. Ratios of Cho to Cr concentrations were elevated in tumors relative to normal brain in vivo. Absolute Cho was some 50% higher in both benign astrocytomas and oligodendrogliomas in vivo than in normal brain. However, Cho concentration in vitro was significantly higher only in pituitary adenomas than in healthy white matter. Total creatine was approximately 50% lower in malignant astrocytomas and meningiomas than in normal brain.
  
  
  CONCLUSIONS
  It is concluded that absolute concentrations of metabolites in vivo yield a different picture of tumor metabolites than that derived from uncorrected metabolite ratios.
authors.affiliation: Department of Clinical Radiology, Kuopio University Hospital, Finland.
authors.forename: J P
authors.initials: JP
authors.lastname: Usenius
authors.forename: R A
authors.initials: RA
authors.lastname: Kauppinen
authors.forename: P A
authors.initials: PA
authors.lastname: Vainio
authors.forename: J A
authors.initials: JA
authors.lastname: Hernesniemi
authors.forename: M P
authors.initials: MP
authors.lastname: Vapalahti
authors.forename: L A
authors.initials: LA
authors.lastname: Paljärvi
authors.forename: S
authors.initials: S
authors.lastname: Soimakallio
mesh_terms: D000236:Adenoma / Q000378:metabolism; D000328:Adult; D001224:Aspartic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D001254:Astrocytoma / Q000378:metabolism; D001834:Body Water / Q000378:metabolism; D001921:Brain / Q000378:metabolism; D001932:Brain Neoplasms / Q000378:metabolism*; D002794:Choline / Q000378:metabolism; D003401:Creatine / Q000378:metabolism; D046508:Culture Techniques; D006801:Humans; D006859:Hydrogen; D009682:Magnetic Resonance Spectroscopy; D008579:Meningioma / Q000378:metabolism; D009837:Oligodendroglioma / Q000378:metabolism; D010911:Pituitary Neoplasms / Q000378:metabolism
chemical_list: D001224:Aspartic Acid; D006859:Hydrogen; C000179:N-acetylaspartate; D003401:Creatine; D002794:Choline