Quantification of tumor microvascular permeability in human glioma xenografts using dynamic T1 MRI with Gadomer-17

Dynamic Magnetic Resonance Imaging (T1-mapping) using the Gadolinium complex Gadomer-17, was applied to characterize the vascular permeability of human glioma xenografts implanted in nude mice. We aimed at measuring permeability differences in two types of glioma xenograft lines with a known difference in perfusion status. The T1-data could be analyzed according to the Tofts-Kermode compartmental model for modeling tracer kinetics to vascular permeability. This vascular permeability was mapped as the permeability surface area product per unit of leakage volume (k). The two tumor types displayed different k-maps. For the fast growing E102 tumor, we observed a homogeneous distribution of the vascular permeability across the tumor with a mean k-value of (0.207 plus or minus 0.027) min-1. However, for the slowly growing E106 tumor, we could distinguish four different regions with different permeability characteristics: a well-perfused rim [k equals (0.30 plus or minus 0.09) min-1], regions at the inner side of the tumor with lower permeability [k equals (0.130 plus or minus 0.019) min-1], regions at the inner side of the tumor around necrotic regions demonstrating locally increased permeability [k equals (0.33 plus or minus 0.11) min-1], and necrotic regions.