1: Magn Reson Med. 2006 Nov;56(5):1041-9. Determination of the maturity and functionality of tumor vasculature by MRI: correlation between BOLD-MRI and DCE-MRI using P792 in experimental fibrosarcoma tumors. Baudelet C, Cron GO, Gallez B. Laboratory of Biomedical Magnetic Resonance, Université Catholique de Louvain, Brussels, Belgium. 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 (K(in) (Trans)) or contrast agent efflux rate (k(ep)). 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 (V(p)), were only weakly correlated (r(2) = 0.02-0.14). Furthermore, VF showed no correlation with K(in) (Trans). A positive correlation was observed (r(2) = 0.75) between mean tumor VF and k(ep), 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. (c) 2006 Wiley-Liss, Inc. PMID: 16986109 [PubMed - indexed for MEDLINE] Related Links The role of vessel maturation and vessel functionality in spontaneous fluctuations of T2*-weighted GRE signal within tumors. [NMR Biomed. 2006] PMID:16411170 PTK787/ZK222584, a tyrosine kinase inhibitor of vascular endothelial growth factor receptor, reduces uptake of the contrast agent GdDOTA by murine orthotopic B16/BL6 melanoma tumours and inhibits their growth in vivo. [NMR Biomed. 2005] PMID:15918178 Noninvasive monitoring of radiotherapy-induced microvascular changes using dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) in a colorectal tumor model. [Int J Radiat Oncol Biol Phys. 2006] PMID:16457965 Physiological noise in murine solid tumours using T2*-weighted gradient-echo imaging: a marker of tumour acute hypoxia? [Phys Med Biol. 2004] PMID:15379021 Quantitative dynamic contrast-enhanced MRI in tumor-bearing rats and mice with inversion recovery TrueFISP and two contrast agents at 4.7 T. [J Magn Reson Imaging. 2006] PMID:16878308