title: Multivoxel MR spectroscopic imaging--distinguishing intracranial tumours from non-neoplastic disease.
abstract: BACKGROUND
  Multi-voxel MR spectroscopic imaging (MRSI) provides chemical metabolite information that can supplement conventional MR imaging in the study of intracranial neoplasia. Our purpose was to use a robust semi-automated spectroscopic analysis to distinguish intracranial tumours from non-neoplastic disease.
  
  
  METHODS
  Twenty intracranial tumours and 15 patients with non-neoplastic disease confirmed on histological examination or serial neuroimaging were studied with 2-dimensional MRSI using point-resolved spectroscopic (PRESS) imaging localisation. Using semi-automated post-processing software, spectra were analysed for peak heights of choline (Cho), creatine (Cr), N-acetyl aspartate (NAA), lactate (Lac) and lipid (Lip). Normalised Cho (nCho) ratios, computed by dividing maximum Cho in the lesion by the normal-appearing brain, were compared between intracranial tumours and non-neoplastic disease.
  
  
  RESULTS
  Meningiomas displayed homogeneously elevated Cho. Malignant tumours, especially large glioblastoma multiforme, displayed inhomogeneity of metabolites within the tumour. All tumours had elevation of nCho >1 (mean 1.91 +/- 0.65), and non-neoplastic diseases had tumour nCho <1 (mean 0.91 +/- 0.46), which was significantly lower (P <0.05). Two patients with non-neoplastic lesions, one with subacute cerebral infarction and the other with cryptococcoma, had elevated Cho compared to normal tissue (false positive rate 13%).
  
  
  CONCLUSIONS
  Using semi-automated MRSI method, a simplified normalised Cho algorithm provides a method to distinguish intracranial tumours from non-neoplastic disease.
authors.affiliation: Department of Neuroradiology, National Neuroscience Institute, 11 Jalan Tan Tock Seng, Singapore 308433.
authors.forename: Veena Arpit
authors.initials: VA
authors.lastname: Nagar
authors.forename: Jieru
authors.initials: J
authors.lastname: Ye
authors.forename: Maosheng
authors.initials: M
authors.lastname: Xu
authors.forename: Wai-Hoe
authors.initials: WH
authors.lastname: Ng
authors.forename: Tseng-Tsai
authors.initials: TT
authors.lastname: Yeo
authors.forename: Peck-Leong
authors.initials: PL
authors.lastname: Ong
authors.forename: C C Tchoyoson
authors.initials: CC
authors.lastname: Lim
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000032:analysis; D001932:Brain Neoplasms / Q000175:diagnosis* / Q000378:metabolism; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies
chemical_list: D014408:Biomarkers, Tumor