title: Intra-operative characterization of gliomas by near-infrared spectroscopy: possible association with prognosis.
abstract: BACKGROUND
  Growth and expansion of gliomas are highly dependent on vascular neogenesis. An association of microvascular density and tumour energy metabolism is assumed in most human gliomas. The purpose of this investigation was to characterize a series of gliomas by intra-operative near-infrared spectroscopy (NIRS), and to elucidate the relationship between microvascular blood volume (BV), oxygen saturation (SaO(2)), histology and patient survival.
  
  
  METHODS
  The study included 13 patients with gliomas, in whom complete tumour resection according to postoperative magnetic resonance imaging criteria was achieved. Intra-operatively, one low grade astrocytoma, five anaplastic astrocytomas and seven glioblastomas with the ipsilateral cortex were investigated by NIRS revealing capillary BV (total haemoglobin) and SaO(2). Intratumoural BV (tBV) and SaO(2) (tSaO(2)) were additionally used in relation to histology and survival.
  
  
  RESULTS
  The mean tBV of the astrocytomas was 4.96 mg/ml compared to 18.40 mg/ml in the glioblastoma group. Mean tSaO(2) was 36% in the astrocytoma group and 52% in the glioblastomas, respectively. Both tBV and tSaO(2) were significantly higher (p<0.01) in the glioblastoma group. Median survival time was shortest for patients with glioblastoma (12.5 months), with tBV >10/mg/ml (10 months), and tSaO(2) >50% (10 months). Longest median survival times were observed in the astrocytoma group (32.5 months), in patients with Tbv <10/mg/ml (30 months), and tSaO(2) <50% (27.5 months). The differences were highly significant (p<0.01).
  
  
  CONCLUSIONS
  Intra-operative characterization of gliomas by NIRS is feasible. High tBV represents extensive angiogenetic activity of the tumour, whereas high tSaO(2) may be result of non-oxidative glucose metabolism with less oxygen extraction from the capillary bed of the tumour. However, the extent of tBV and tSaO(2) are both of possible prognostic value thus resulting in additional information about the tumour.
authors.affiliation: Department of Neurosurgery, University Hospital, Essen, Germany. siamek.asgari@uni-essen.de
authors.forename: S
authors.initials: S
authors.lastname: Asgari
authors.forename: H J
authors.initials: HJ
authors.lastname: Röhrborn
authors.forename: T
authors.initials: T
authors.lastname: Engelhorn
authors.forename: D
authors.initials: D
authors.lastname: Stolke
mesh_terms: D000328:Adult; D000368:Aged; D001254:Astrocytoma / Q000098:blood supply* / Q000473:pathology / Q000503:physiopathology*; D001810:Blood Volume; D001932:Brain Neoplasms / Q000098:blood supply* / Q000473:pathology / Q000503:physiopathology*; D005260:Female; D005909:Glioblastoma / Q000098:blood supply* / Q000473:pathology / Q000503:physiopathology*; D005947:Glucose / Q000378:metabolism; D006801:Humans; D008297:Male; D008833:Microcirculation; D008875:Middle Aged; D016343:Monitoring, Intraoperative; D009389:Neovascularization, Pathologic; D010100:Oxygen / Q000032:analysis; D011237:Predictive Value of Tests; D011379:Prognosis; D019265:Spectroscopy, Near-Infrared; D016019:Survival Analysis
chemical_list: D005947:Glucose; D010100:Oxygen