title: MR spectroscopy in the evaluation of enhancing lesions in the brain in multiple sclerosis.
abstract: OBJECTIVE
  To compare proton MR spectroscopic alterations with the degree of contrast enhancement in multiple sclerosis (MS) lesions.
  
  
  METHODS
  Thirty-five patients with clinically diagnosed MS were studied with MR spectroscopy. A total of 47 lesions were examined. Solvent-suppressed proton spectra were acquired with an echo time of 16 milliseconds using the point-resolved spectroscopic localization method from 1.5 cm3 voxels. Marker peaks/creatine (Cr) ratios obtained from these spectra were plotted against the relative enhancement of the lesion seen after administration of contrast material. The relative enhancement was defined as S(contrast) -S0/S0, where S0 is the signal intensity of a T1-weighted image and S(contrast) is the signal intensity after administration of gadopentetate dimeglumine.
  
  
  RESULTS
  We found a positive linear relationship between the marker peaks/Cr ratio and the degree of enhancement of the lesion. That is, the marker peaks/Cr ratio was higher in the lesions that showed the greatest enhancement.
  
  
  CONCLUSIONS
  The MR/Cr ratio obtained with the use of short-echo-time proton MR spectroscopy correlates with the degree of contrast enhancement. This ratio may therefore serve as a means for evaluating and quantifying the level of inflammatory activity within the plaques of patients with MS.
authors.affiliation: Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia 19104, USA.
authors.forename: J A
authors.initials: JA
authors.lastname: Hirsch
authors.forename: R E
authors.initials: RE
authors.lastname: Lenkinski
authors.forename: R I
authors.initials: RI
authors.lastname: Grossman
mesh_terms: D001224:Aspartic Acid / Q000031:analogs & derivatives / Q000032:analysis; D001921:Brain / Q000378:metabolism* / Q000473:pathology*; D002794:Choline / Q000032:analysis; D003404:Creatinine / Q000032:analysis; D006801:Humans; D007294:Inositol / Q000032:analysis; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy; D009103:Multiple Sclerosis / Q000175:diagnosis* / Q000378:metabolism
chemical_list: D001224:Aspartic Acid; D007294:Inositol; C000179:N-acetylaspartate; D003404:Creatinine; D002794:Choline