title: Comparison of permeability in high-grade and low-grade brain tumors using dynamic susceptibility contrast MR imaging.
abstract: OBJECTIVE
  The purpose of this study was to compare permeability measurements in high-grade and low-grade glial neoplasms using a T2(*)-weighted method. Our hypothesis was that permeability measurements using a T2(*)-weighted technique would show permeability in high-grade neoplasms to be higher than that in low-grade neoplasms.
  
  
  METHODS
  Twelve patients with biopsy-proven high-grade neoplasms and 10 patients with biopsy-proven low-grade neoplasms underwent dynamic susceptibility contrast MR perfusion imaging (TR/TE, 1500/80) after bolus infusion of 0.2 mmol/kg of MR contrast material. Color-coded permeability-weighted maps were created using a model that weights relative contributions to signal intensity from intravascular T2(*) effects and extravascular T1 effects from blood-brain barrier permeability. Two measures of permeability were performed: mean value of highest permeability found on three images through the tumor (mean regional value) and highest value found at any region of interest in the tumor (single area of maximum permeability). Depending on the normality of the data sets, we used the Wilcoxon's rank sum test or the two-tailed Student's t test for statistical analysis.
  
  
  RESULTS
  For low-grade tumors, the range was 0.006-0.041, and the median of the mean regional value for each image was 0.017. For high-grade tumors, the range was 0.005-0.092, and the median of the mean regional value was 0.035 (p = 0.025). For low-grade tumors, the range was 0.008-0.045, and the mean of the single area of maximum values was 0.02. For high-grade tumors, the range was 0.007-0.136, and the mean of the single area of maximum values was 0.054 (p = 0.018).
  
  
  CONCLUSIONS
  Permeability values for high-grade tumors obtained using a T2(*)-weighted method were significantly greater than those for low-grade tumors and are consistent with previous studies reporting results using T1-weighted methods.
authors.affiliation: Department of Radiology, Duke University Medical Center, Box 3808, Durham, NC 27710, USA.
authors.forename: James M
authors.initials: JM
authors.lastname: Provenzale
authors.forename: Gin R
authors.initials: GR
authors.lastname: Wang
authors.forename: Thomas
authors.initials: T
authors.lastname: Brenner
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Petrella
authors.forename: A Gregory
authors.initials: AG
authors.lastname: Sorensen
mesh_terms: D000328:Adult; D000368:Aged; D001932:Brain Neoplasms / Q000098:blood supply* / Q000175:diagnosis / Q000473:pathology; D002199:Capillary Permeability; D003287:Contrast Media; D019786:Gadolinium DTPA; D005910:Glioma / Q000098:blood supply* / Q000175:diagnosis / Q000473:pathology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods; D008875:Middle Aged; D012189:Retrospective Studies; D013788:Thalamus / Q000098:blood supply
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA