title: Evaluation of perfusion CT in grading and prognostication of high-grade gliomas at diagnosis: a pilot study.
abstract: OBJECTIVE
  Differentiation of grade 3 astrocytoma from glioblastoma multiforme can be difficult with conventional structural imaging but is important for prognosis. The purpose of this study was to assess perfusion CT in differentiating high-grade gliomas (HGGs) and their role in prognosis in the care of patients with HGG.
  
  
  METHODS
  Twenty patients with previously untreated HGG underwent prospective evaluation with perfusion CT. Permeability surface area product (PS) and cerebral blood volume (CBV) were calculated by the deconvolution method and were compared between HGGs with Student two-sample t tests. Receiver operating characteristic curves were generated for PS, CBV, and the conjoint factor PS + CBV. Cox regression analysis was used to correlate these parameters with patient survival over a follow-up period. Hazard ratios were calculated, and Kaplan-Meier survival curves were drawn.
  
  
  RESULTS
  There was a significant difference between grade 3 and grade 4 gliomas for PS (p = 0.022) and PS + CBV (p = 0.019) but not for CBV alone (p = 0.411). Receiver operating characteristic analyses showed that PS (area under the curve [AUC], 0.72) and CBV + PS (AUC, 0.73) can be used to differentiate grade 3 from grade 4 gliomas but that CBV alone cannot be so used (AUC, 0.54). There was a significant relation between patient outcome and age (p = 0.034) and CBV + PS (p = 0.048). Patients with HGG and a CBV + PS greater than 9 had a poor outcome (hazard ratio, 6.00).
  
  
  CONCLUSIONS
  PS and CBV + PS can be used to differentiate grade 3 from grade 4 gliomas. The outcome of patients with HGG depends on age and CBV + PS.
authors.affiliation: Department of Diagnostic Imaging, QEII Hospital, Halifax, Canada. shivajai1@rediffmail.com
authors.forename: Jai Jai Shiva
authors.initials: JJ
authors.lastname: Shankar
authors.forename: John
authors.initials: J
authors.lastname: Woulfe
authors.forename: Vasco Da
authors.initials: VD
authors.lastname: Silva
authors.forename: Thanh B
authors.initials: TB
authors.lastname: Nguyen
mesh_terms: D001932:Brain Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology*; D002533:Cerebral Angiography / Q000379:methods*; D003287:Contrast Media; D005260:Female; D005910:Glioma / Q000000981:diagnostic imaging / Q000473:pathology*; D006801:Humans; D007472:Iohexol; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D055420:Perfusion Imaging / Q000379:methods*; D010865:Pilot Projects; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media; D007472:Iohexol