title: Pharmacokinetic modeling of Gd-DTPA extravasation in brain tumors.
abstract: OBJECTIVE
  The endothelial permeability of brain tumors affecting the blood-brain barrier can be quantified using dynamic contrast enhanced MR imaging.
  
  
  METHODS
  The dynamics of contrast medium (CM) exchange was investigated in 31 brain tumors (intra- and extra-axial) by fast repeated T1-weighted imaging in order to determine the exchange rates and saturation concentrations.
  
  
  RESULTS
  The analysis of CM exchange reveals two different transport processes from the blood into two separate interstitial subcompartments for intra- and extra-axial tumors, a rapid one with a transfer constant of 1/ =7.0 seconds and a slow one with 1/ =133.7 seconds. Highly significant differences exhibit gliomas and meningiomas with respect to the saturation concentrations of fast and slowly enhancing compartments.
  
  
  CONCLUSIONS
  The fast component is probably caused by extravasation into viable tissue (enhanced in meningiomas) while the slow one probably reflects increased diffusion distances into poorly perfused tissue such as necrotic areas in glioblastomas.
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001812:Blood-Brain Barrier; D001932:Brain Neoplasms / Q000098:blood supply / Q000175:diagnosis* / Q000473:pathology; D002560:Cerebrovascular Circulation; D002648:Child; D003287:Contrast Media / Q000493:pharmacokinetics*; D005119:Extravasation of Diagnostic and Therapeutic Materials; D005260:Female; D019786:Gadolinium DTPA / Q000493:pharmacokinetics*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA