title: ¹H-MRS of intracranial meningiomas: what it can add to known clinical and MRI predictors of the histopathological and biological characteristics of the tumor?
abstract: OBJECTIVE
  The main goal of the present study was evaluation of proton magnetic resonance spectroscopy (¹H-MRS) in diagnosis of histopathologically aggressive intracranial meningiomas.
  
  
  METHODS
  Single-voxel ¹H-MRS of 100 intracranial meningiomas was performed before their surgical resection. Investigated metabolites included mobile lipids, lactate, alanine, N-acetylaspartate (NAA), and choline-containing compounds (Cho). According to criteria of World Health Organization (WHO) 82 meningiomas were assigned histopathological grade I, 11 grade II, and 7 grade III. The MIB-1 index varied from 0% to 27.3% (median, 1.6%). In 43 cases tight adhesion of the tumor to the pia mater or brain tissue was macroscopically identified at surgery. The consistency of 49 meningiomas was characterized as soft, 26 as hard, and 25 as mixed.
  
  
  RESULTS
  No one metabolic parameter had statistically significant association with histopathological grade and subtype, invasive growth, and consistency of meningioma. Univariate statistical analysis revealed greater ¹H-MRS-detected Cho content (P=0.0444) and lower normalized NAA/Cho ratio (P=0.0203) in tumors with MIB-1 index 5% and more. However, both parameters lost their statistical significance during evaluation in the multivariate model along with other clinical and radiological variables. It was revealed that non-benign histopathology of meningioma (WHO grade II/III) is mainly predicted by irregular shape (P=0.0076) and large size (P=0.0316), increased proliferative activity by irregular shape (P=0.0056), and macroscopically invasive growth by prominent peritumoral edema (P=0.0021).
  
  
  CONCLUSIONS
  While ¹H-MRS may be potentially used for the identification of meningiomas with high proliferative activity, it, seemingly, could not add substantial diagnostic information to other radiological predictors of malignancy in these tumors.
authors.affiliation: International Research and Educational Institute for Integrated Medical Sciences (IREIIMS), Tokyo Women's Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo 162-8666, Japan. m chernov@yahoo.com
authors.forename: Mikhail F
authors.initials: MF
authors.lastname: Chernov
authors.forename: Hidetoshi
authors.initials: H
authors.lastname: Kasuya
authors.forename: Kotaro
authors.initials: K
authors.lastname: Nakaya
authors.forename: Koichi
authors.initials: K
authors.lastname: Kato
authors.forename: Yuko
authors.initials: Y
authors.lastname: Ono
authors.forename: Shigetoshi
authors.initials: S
authors.lastname: Yoshida
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Muragaki
authors.forename: Takashi
authors.initials: T
authors.lastname: Suzuki
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Iseki
authors.forename: Osami
authors.initials: O
authors.lastname: Kubo
authors.forename: Tomokatsu
authors.initials: T
authors.lastname: Hori
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Okada
authors.forename: Kintomo
authors.initials: K
authors.lastname: Takakura
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D050356:Lipid Metabolism; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008579:Meningioma / Q000378:metabolism* / Q000473:pathology*; D008875:Middle Aged; D009361:Neoplasm Invasiveness / Q000473:pathology; D009367:Neoplasm Staging; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D055815:Young Adult
chemical_list: D014408:Biomarkers, Tumor