title: Intratumor distribution and test-retest comparisons of physiological parameters quantified by dynamic contrast-enhanced MRI in rat U251 glioma.
abstract: The distribution of dynamic contrast-enhanced MRI (DCE-MRI) parametric estimates in a rat U251 glioma model was analyzed. Using Magnevist as contrast agent (CA), 17 nude rats implanted with U251 cerebral glioma were studied by DCE-MRI twice in a 24 h interval. A data-driven analysis selected one of three models to estimate either (1) plasma volume (vp), (2) vp and forward volume transfer constant (K(trans)) or (3) vp, K(trans) and interstitial volume fraction (ve), constituting Models 1, 2 and 3, respectively. CA distribution volume (VD) was estimated in Model 3 regions by Logan plots. Regions of interest (ROIs) were selected by model. In the Model 3 ROI, descriptors of parameter distributions--mean, median, variance and skewness--were calculated and compared between the two time points for repeatability. All distributions of parametric estimates in Model 3 ROIs were positively skewed. Test-retest differences between population summaries for any parameter were not significant (p ≥ 0.10; Wilcoxon signed-rank and paired t tests). These and similar measures of parametric distribution and test-retest variance from other tumor models can be used to inform the choice of biomarkers that best summarize tumor status and treatment effects.
authors.affiliation: Department of Neurology, Henry Ford Hospital, Detroit, MI, USA.
authors.forename: Madhava P
authors.initials: MP
authors.lastname: Aryal
authors.forename: Tavarekere N
authors.initials: TN
authors.lastname: Nagaraja
authors.forename: Stephen L
authors.initials: SL
authors.lastname: Brown
authors.forename: Mei
authors.initials: M
authors.lastname: Lu
authors.forename: Hassan
authors.initials: H
authors.lastname: Bagher-Ebadian
authors.forename: Guangliang
authors.initials: G
authors.lastname: Ding
authors.forename: Swayamprava
authors.initials: S
authors.lastname: Panda
authors.forename: Kelly
authors.initials: K
authors.lastname: Keenan
authors.forename: Glauber
authors.initials: G
authors.lastname: Cabral
authors.forename: Tom
authors.initials: T
authors.lastname: Mikkelsen
authors.forename: James R
authors.initials: JR
authors.lastname: Ewing
mesh_terms: D000818:Animals; D014408:Biomarkers, Tumor; D001932:Brain Neoplasms / Q000098:blood supply / Q000737:chemistry* / Q000473:pathology; D045744:Cell Line, Tumor; D003287:Contrast Media / Q000493:pharmacokinetics*; D019786:Gadolinium DTPA / Q000493:pharmacokinetics*; D005909:Glioblastoma / Q000098:blood supply / Q000737:chemistry* / Q000473:pathology; D064593:Heterografts; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008954:Models, Biological; D009368:Neoplasm Transplantation; D059906:Neuroimaging / Q000379:methods*; D010949:Plasma; D011522:Protons; D051381:Rats; D011923:Rats, Nude; D018709:Statistics, Nonparametric; D014018:Tissue Distribution
chemical_list: D014408:Biomarkers, Tumor; D003287:Contrast Media; D011522:Protons; D019786:Gadolinium DTPA
keywords: Ktrans; Logan plot; Magnevist; Patlak plot; distribution volume; interstitial volume