The diagnostic efficiency of the perfusion-related parameters in assessing the vascular disrupting agent (CA4P) response in a rabbit VX2 liver tumor model.

BACKGROUND: There are inconsistencies when concomitantly using dynamic contrast enhancement (DCE) and intravoxel incoherent motion (IVIM) to evaluate diagnostic efficiency. PURPOSE: To evaluate the diagnostic efficiency of perfusion-related parameters in assessing the effect of Combretastatin-A4-phosphate (CA4P) in a rabbit VX2 liver tumor model using DCE and IVIM. MATERIAL AND METHODS: Twenty rabbits implanted with VX2 tumors were included in the study. The perfusion-parameters of DCE (Ktrans and iAUC60) and IVIM (f and D*) were measured at baseline and 4 h after administration of CA4P. Subsequently, the rabbits were euthanized. Pre- and post-treatment perfusion parameters were analyzed using paired t-test. Correlation between the various perfusion parameters and correlation of perfusion parameters with microvascular density (MVD) were assessed using Pearson correlation analysis. The diagnostic efficiency was evaluated using receiver operating characteristic (ROC) curve analysis. RESULTS: All perfusion parameters (Ktrans, iAUC60, f and D*) showed significant decrease after 4 h of CA4P administration (all P < 0.001). Post-treatment perfusion parameters showed a moderate correlation with MVD (r = 0.663, r = 0.567, r = 0.685, r = 0.618, respectively; all P < 0.05). At baseline and after treatment, Ktrans values and iAUC60 showed correlation with f and D* (all P < 0.05). Concomitant use of perfusion parameters of DCE and IVIM showed the best diagnostic performance, which was slightly greater than that observed with individual application of DCE or IVIM (AUC = 0.915, 0.880, and 0.895, respectively). CONCLUSION: Although concomitant application of DCE and IVIM can slightly improve the diagnostic value in assessing the effect of CA4P, the values were relatively small.