Determination of the maturity and functionality of tumor vasculature by MRI: Correlation between BOLD-MRI and DCE-MRI using P792 in experimental fibrosarcoma tumors

Using hypercapnia and carbogen as functional markers of vessel maturation and function, we compared blood oxygen level‐dependent (BOLD) contrast with standard dynamic contrast‐enhanced (DCE)‐MRI quantitative parameters in murine fibrosarcoma. Our results show that there was no correlation between vessel maturity and contrast‐agent uptake rate (KinTrans) or contrast agent efflux rate (kep). In addition, DCE‐MRI provided higher estimates of the fraction of functional tumor compared to BOLD‐MRI. The two putative markers of regional vascular density, i.e., the magnitude of BOLD signal change during carbogen challenge (VF) and the fractional plasma volume found by DCE‐MRI (Vp), were only weakly correlated (r2 = 0.02–0.14). Furthermore, VF showed no correlation with KinTrans. A positive correlation was observed (r2 = 0.75) between mean tumor VF and kep, but only when averaged over the whole tumor (which includes tumor regions completely unperfused by the gadolinium (Gd) contrast agent). This would merely reveal a relationship between perfusion status and the capacity to respond to carbogen breathing. In conclusion, characterizations of tumor microvasculature imaging using BOLD‐MRI and DCE‐MRI appear to be largely complementary, given the weak correlations between their corresponding derived parameters. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.