title: MR spectroscopy differentiation between high and low grade astrocytomas: a comparison between paediatric and adult tumours.
abstract: OBJECTIVE
  To investigate whether pathologically similar astrocytomas in adults and children may also show metabolic similarities in proton magnetic resonance spectroscopy ((1)H-MRS) and whether the MRS data could help to differentiate between low and high grade gliomas for the different groups.
  
  
  METHODS
  Twelve children (5 WHO II astrocytomas, 7 WHO III astrocytomas) and 37 adults (21 WHO II astrocytomas, 16 WHO III astrocytomas) were included in this study. MR spectroscopic data were evaluated retrospectively using normalized measures of total choline (tCho), N-acetyl-aspartate (NAA) and total creatine (tCr). These metabolites were used to differentiate between WHO II and WHO III astrocytomas in children and adults. Histopathological grading was performed using WHO criteria. (1)H-MRS was carried out prior to the commencement of any treatment. Signal intensities of tCho, NAA and tCr were normalized to their values in contralateral brain tissue. The resulting concentration ratios were then used to calculate the change in the intratumoural ratio of NAA to tCho. A Mann-Whitney U-Test was performed to evaluate differences within the respective groups.
  
  
  RESULTS
  In both groups, loss of NAA and increase of tCho were more pronounced in WHO III than in WHO II astrocytoma. The best discriminator to differentiate between low and high grade gliomas was found to be the ratio of NAA/tCho (p < 0.01).
  
  
  CONCLUSIONS
  The normalized metabolite signal intensities ratio NAA to tCho is the most accurate in differentiating between low and high grade astrocytomas in both children and adults.
authors.affiliation: Neuroradiology Department of the Johann Wolfgang Goethe University, Frankfurt/Main, Germany. luciana.porto@kgu.de
authors.forename: Luciana
authors.initials: L
authors.lastname: Porto
authors.forename: Matthias
authors.initials: M
authors.lastname: Kieslich
authors.forename: Kea
authors.initials: K
authors.lastname: Franz
authors.forename: Thomas
authors.initials: T
authors.lastname: Lehrnbecher
authors.forename: Friedhelm
authors.initials: F
authors.lastname: Zanella
authors.forename: Ulrich
authors.initials: U
authors.lastname: Pilatus
authors.forename: Elke
authors.initials: E
authors.lastname: Hattingen
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000367:Age Factors; D000368:Aged; D001254:Astrocytoma / Q000175:diagnosis* / Q000378:metabolism*; D001932:Brain Neoplasms / Q000175:diagnosis* / Q000378:metabolism*; D002648:Child; D002675:Child, Preschool; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods / Q000592:standards* / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012189:Retrospective Studies