title: Elevated peritumoural rCBV values as a mean to differentiate metastases from high-grade gliomas.
abstract: OBJECTIVE
  Increased relative cerebral blood volume (rCBV) was previously found in peritumoural oedema of glioblastomas (GBM). Supposing that peritumoural rCBV is not increased in metastases, we aimed to evaluate whether rCBV values of the whole peritumoural area are accurate to differentiate solitary metastasis from GBM irrespective of the peritumoural oedema.
  
  
  METHODS
  Contrast-enhanced T1-weighted (T1-w) and T2*-weighted dynamic susceptibility contrast MRI was performed in 52 patients with contrast-enhancing solitary brain tumours before surgery. In each T1-w slice depicting the contrast-enhancing tumour, a rim within approximately 15 mm was defined in the peritumoural area. The rCBV values were normalised to rCBV values of the contralateral normal white matter. Differences between metastases and GBM for normalised rCBV values for each slice were determined with the Mann-Whitney U test (p < 0.05).
  
  
  RESULTS
  Histopathological examination revealed 29 GBM and 23 metastases. Peritumoural rCBV was significantly lower in metastases than in GBM (p < 0.01). Using the cutoff value 1.0 for discriminating metastases from GBM yielded a sensitivity of 96%, specificity of 64%, a positive predictive value of 68% and a negative predictive value of 95%.
  
  
  CONCLUSIONS
  The rCBV in the peritumoural area of contrast-enhancing brain tumours has a high diagnostic accuracy to discriminate metastases from GBM irrespective of surrounding oedema and without the bias of slice selection and ROI positioning. Metastases should be excluded, if at least one tumour-depicting slice reveals an increase of peritumoural rCBV compared to the normal contralateral brain (normalised rCBV value >1). Conversely, the decrease of peritumoural rCBV may not reliably exclude GBM.
authors.affiliation: Institute of Neuroradiology, University of Frankfurt, Schleusenweg 2-16, Frankfurt, 60528, Germany. Stella.Blasel@kgu.de
authors.forename: Stella
authors.initials: S
authors.lastname: Blasel
authors.forename: Alina
authors.initials: A
authors.lastname: Jurcoane
authors.forename: Kea
authors.initials: K
authors.lastname: Franz
authors.forename: Gerald
authors.initials: G
authors.lastname: Morawe
authors.forename: Stefanie
authors.initials: S
authors.lastname: Pellikan
authors.forename: Elke
authors.initials: E
authors.lastname: Hattingen
mesh_terms: D000328:Adult; D000368:Aged; D001932:Brain Neoplasms / Q000098:blood supply* / Q000175:diagnosis* / Q000556:secondary; D002560:Cerebrovascular Circulation / Q000502:physiology*; D003287:Contrast Media; D003937:Diagnosis, Differential; D005260:Female; D005909:Glioblastoma / Q000098:blood supply / Q000175:diagnosis; D005910:Glioma / Q000098:blood supply* / Q000175:diagnosis*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis / Q000175:diagnosis* / Q000503:physiopathology; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D055815:Young Adult
chemical_list: D003287:Contrast Media