Dynamic Contrast Enhanced MRI Parameters and Tumor Cellularity in a Rat Model of Cerebral Glioma at 7 T

PurposeTo test the hypothesis that a noninvasive dynamic contrast enhanced MRI (DCE-MRI) derived interstitial volume fraction (v(e)) and/or distribution volume (V-D) were correlated with tumor cellularity in cerebral tumor. MethodsT(1)-weighted DCE-MRI studies were performed in 18 athymic rats implanted with U251 xenografts. After DCE-MRI, sectioned brain tissues were stained with Hematoxylin and Eosin for cell counting. Using a Standard Model analysis and Logan graphical plot, DCE-MRI image sets during and after the injection of a gadolinium contrast agent were used to estimate the parameters plasma volume (v(p)), forward transfer constant (K-trans), v(e), and V-D. ResultsParameter values in regions where the standard model was selected as the best model were: (mean S.D.): v(p) = (0.81 +/- 0.40)%, K-trans = (2.09 +/- 0.65) x 10(-2) min(-1), v(e) = (6.65 +/- 1.86)%, and V-D = (7.21 +/- 1.98)%. The Logan-estimated V-D was strongly correlated with the standard model's v(p) + v(e) (r = 0.91, P < 0.001). The parameters, v(e) and/or V-D, were significantly correlated with tumor cellularity (r -0.75, P < 0.001 for both). ConclusionThese data suggest that tumor cellularity can be estimated noninvasively by DCE-MRI, thus supporting its utility in assessing tumor pathophysiology. Magn Reson Med 71:2206-2214, 2014. (c) 2013 Wiley Periodicals, Inc.