title: Single voxel proton MR spectroscopy findings of typical and atypical intracranial meningiomas.
abstract: OBJECTIVE
  To prospectively define proton magnetic resonance spectroscopy (MRS) findings of meningiomas, and describe the ability or inability of short- and long-echo MRS to differentiate typical and atypical meningiomas in vivo.
  
  
  METHODS
  Seventeen patients with pathologically confirmed typical meningiomas and six with atypical meningiomas were evaluated with conventional MR imaging and MRS before resection. MRS studies using point-resolved spectroscopy (PRESS) localisation, at short- and long-echo time (TR 2000 ms, TE: 30 and 144 ms, 64-96 acquisition) were acquired on a 1.5 T scanner. MRS data obtained from these patients were compared with histopathological findings. Mean cellular proliferation (MIB-1) antibody staining against the Ki-67 antigen was also determined in all meningiomas.
  
  
  RESULTS
  Prominent choline (Cho) was present in all meningiomas. Alanine (Ala) was observed in 21 cases of the 23 meningiomas. Acetylaspartate (NAA) and creatine (Cr) were either not observed or detected in minimal amounts in at all both groups of meningiomas on long TE (144 ms) spectra. The mean Cho/Cr values in the four atypical meningiomas were 4.44+/-0.30 (mean+/-standard deviation) and 3.39+/-0.52 in the 12 typical meningiomas on short TE spectra. Cho/Cr ratio could not be determined in the other seven cases because of a lack of creatine peak. Of the five meningiomas in which a lactate peak was detected, four were in typical cases and only one was in atypical meningioma. Mean MIB-1 proliferation index was 3.7% in typical meningiomas and 10% in atypical meningiomas.
  
  
  CONCLUSIONS
  Prominent Cho, absence or low amount of NAA and Cr, and presence of Ala were common characteristics of spectral pattern of both atypical and typical meningiomas on MRS. MRS cannot reliably differentiate typical intracranial meningiomas from atypical meningiomas preoperatively. Mean MIB-1 proliferation index was well correlated with histopathology findings.
authors.affiliation: Department of Radiology, Trakya University School of Medicine, Istanbul, Turkey. demirkemal@superonline.com
authors.forename: Mustafa Kemal
authors.initials: MK
authors.lastname: Demir
authors.forename: A Celal
authors.initials: AC
authors.lastname: Iplikcioglu
authors.forename: Alp
authors.initials: A
authors.lastname: Dincer
authors.forename: Mahmut
authors.initials: M
authors.lastname: Arslan
authors.forename: Aydin
authors.initials: A
authors.lastname: Sav
mesh_terms: D000328:Adult; D000368:Aged; D001923:Brain Chemistry; D001932:Brain Neoplasms / Q000145:classification / Q000175:diagnosis*; D003936:Diagnosis, Computer-Assisted / Q000379:methods; D005260:Female; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008297:Male; D008577:Meningeal Neoplasms / Q000737:chemistry* / Q000145:classification / Q000175:diagnosis*; D008579:Meningioma / Q000737:chemistry* / Q000145:classification / Q000175:diagnosis*; D008875:Middle Aged; D011522:Protons; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D011522:Protons