title: Comparison of first-pass and second-bolus dynamic susceptibility perfusion MRI in brain tumors.
abstract: BACKGROUND
  Our goal was to evaluate whether the T1 shortening effect caused by contrast leakage into brain tumors, a well-known confounding effect in the quantification of relative cerebral blood volume (rCBV) measurements, may be corrected by the administration of a predose of gadolinium-DTPA.
  
  
  METHODS
  As part of their presurgical imaging protocol, 25 patients with primary brain tumors underwent two consecutive dynamic susceptibility-weighted contrast-enhanced (DSC) perfusion MR studies. Intratumoral rCBV measurements and normalized rCBV values obtained during the first-pass and second-bolus studies were compared (Wilcoxon signed-ranks test). The frequency of relatively increased rCBV ratios on the second-bolus study was compared between enhancing and non-enhancing neoplasms (Fisher's exact test). Postprocessing perfusion studies were evaluated for image quality on a scale of 0-3 (Wilcoxon signed-ranks test). Four studies were excluded due to unacceptable image quality.
  
  
  RESULTS
  Mean normalized rCBVs were 9.04 (SD 4.64) for the first-pass and 7.99 (SD 3.84) for the second-bolus study. There was no statistically significant difference between the two perfusion studies in either intratumoral rCBV (P=0.237) or rCBV ratio (P=0.181). Five enhancing and four non-enhancing tumors showed a relative increase in rCBV ratio on the second-bolus study, without a significant difference between the groups. Image quality was not significantly different between perfusion studies.
  
  
  CONCLUSIONS
  Our results did not demonstrate a significant difference between first-pass and second-bolus rCBV measurements in DSC perfusion MR imaging. The administration of a predose of gadolinium-DTPA does not appear to be an efficient way of compensating for the underestimation of intratumoral rCBV values due to the T1 shortening effect.
authors.affiliation: Department of Radiology, Medical University of South Carolina, 169 Ashley Avenue, P.O. Box 250322, Charleston, SC 29425, USA. spampin@musc.edu
authors.forename: M Vittoria
authors.initials: MV
authors.lastname: Spampinato
authors.forename: Caroline
authors.initials: C
authors.lastname: Wooten
authors.forename: Margaret
authors.initials: M
authors.lastname: Dorlon
authors.forename: Nada
authors.initials: N
authors.lastname: Besenski
authors.forename: Zoran
authors.initials: Z
authors.lastname: Rumboldt
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001932:Brain Neoplasms / Q000175:diagnosis*; D002560:Cerebrovascular Circulation; D002648:Child; D002675:Child, Preschool; D003287:Contrast Media / Q000008:administration & dosage*; D005240:Feasibility Studies; D005260:Female; D019786:Gadolinium DTPA / Q000008:administration & dosage*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D018709:Statistics, Nonparametric
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA