title: The effect of paramagnetic contrast in choline peak in patients with glioblastoma multiforme might not be significant.
abstract: OBJECTIVE
  (1)H-MR spectroscopy is a useful tool in brain tumor evaluation. A critical point in obtaining representative spectra is the correct voxel positioning, which can be more accurate after Gd administration. Some experimental data suggested that Gd could cause Cho signal loss. Our aim was to evaluate the effect of Gd in the Cho peak area and width in patients with GBM.
  
  
  METHODS
  We performed multivoxel (1)H-MR spectroscopy before and after Gd administration in 18 patients with GBM. Quantification of Cho peak area and width in each voxel was completed, and the Cho mean and maximum values before and after Gd injection were calculated in the tumor and contralateral hemisphere. Choline peak area and width values obtained before and after contrast were compared, considering as separate entities enhancing and nonenhancing tumoral voxels and the contralateral hemisphere.
  
  
  RESULTS
  No statistically significant differences were found for the Cho peak area mean values in the tumoral voxels or contralaterally (P > .05). A tendency for an increase in the Cho peak width mean value was found in the tumoral enhancing voxels (P = .055). A statistically significant decrease was found for the mean value of the maximum Cho peak area in enhancing tumoral voxels (P = .020). No significant differences were found in the nonenhancing tumoral voxels or contralaterally (P > .05).
  
  
  CONCLUSIONS
  The injection of Gd before performing (1)H-MR spectroscopy might not significantly affect the Cho peak area in patients with GBM. The paramagnetic contrast seems to cause a different effect, depending on Gd enhancement.
authors: Department of Radiology, University of Sao Paulo, Sao Paulo, Brazil. eduardocl@einstein.br
authors: E C
authors: EC
authors: Lima
authors: M C G
authors: MC
authors: Otaduy
authors: M
authors: M
authors: Tsunemi
authors: R
authors: R
authors: Pincerato
authors: E F
authors: EF
authors: Cardoso
authors: S
authors: S
authors: Rosemberg
authors: P H
authors: PH
authors: Aguiar
authors: G G
authors: GG
authors: Cerri
authors: C C
authors: CC
authors: Leite
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001921:Brain / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D001932:Brain Neoplasms / Q000175:diagnosis / Q000378:metabolism*; D002794:Choline / Q000032:analysis*; D003287:Contrast Media / Q000008:administration & dosage; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods*; D005260:Female; D005682:Gadolinium / Q000008:administration & dosage; D005909:Glioblastoma / Q000175:diagnosis / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media; D005682:Gadolinium; D002794:Choline