Dynamic contrast-enhanced MRI using macromolecular contrast media for monitoring the response to isolated limb perfusion in experimental soft-tissue sarcomas

The objective of this study was to evaluate the potential of dynamic contrast-enhanced MRI for quantitative characterization of tumor microvessels and to assess the microvascular changes in response to isolated limb perfusion with TNF-alpha and melphalan. Dynamic contrast-enhanced MRI was performed in an experimental cancer model, using a macromolecular contrast medium, albumin-(Gd-DTPA)(45)- Small fragments of BN 175, a soft-tissue sarcoma, were implanted in I I brown Norway (BN) rats. Animals were assigned randomly to a control (Haemaccel) or drug-treated group (TNF-alpha/melphalan). MRI was performed at baseline and 24 h after ILP. The transendothelial permeability (K-PS) and the fractional plasma volume (fPV) were estimated from the kinetic analysis of MR data using a two-compartment bi-directional model. K-PS and fPV decreased significantly in the drug-treated group compared to baseline (p < 0.05). In addition, K-PS post therapy was significantly lower (p < 0.05) in the drug-treated group than in the control group. There was no significant difference in fPV between the drug-treated and the control group after therapy Tumor microvascular changes in response to isolated limb perfusion can be determined after 24 h by dynamic contrast-enhanced MRI. The data obtained in this experimental model suggest possible applications in the clinical setting, using the appropriate MR contrast agents.