Dynamic Contrast-Enhanced MRI for Monitoring Antiangiogenic Treatment: Determination of Accurate and Reliable Perfusion Parameters in a Longitudinal Study of a Mouse Xenograft Model

Objective: To determine the reliable perfusion parameters in dynamic contrast-enhanced MRI (DCE-MRI) for the monitoring antiangiogenic treatment in mice. Materials and Methods: Mice, with U-118 MG tumor, were treated with either saline (n = 3) or antiangiogenic agent (sunitinib, n = 8). Before (day 0) and after (days 2, 8, 15, 25) treatment, DCE examinations using correlations of perfusion parameters (Kep, Kel, and AH from two compartment model; time to peak, initial slope and % enhancement from time-intensity curve analysis) were evaluated. Results: Tumor growth rate was found to be 129 % ± 28 in control group,-33 % ± 11 in four mice with sunitinib-treatment (tumor regression) and 47 % ± 15 in four with sunitinib-treatment (growth retardation). Kep (r = 0.80) and initial slope (r = 0.84) showed strong positive correlation to the initial tumor volume (p < 0.05). In control mice, tumor regression group and growth retardation group animals, Kep (r: 0.75, 0.78, 0.81, 0.69) and initial slope (r: 0.79, 0.65, 0.67, 0.84) showed significant correlation with tumor volume (p < 0.01). In four mice with tumor re-growth, Kep and initial slope increased 20 % or greater at earlier (n = 2) than or same periods (n = 2) to when the tumor started to re-grow with 20 % or greater growth rate