Correlation of quantitative dynamic contrast-enhanced MRI with microvascular density in necrotic, partial necrotic, and viable liver tumors in a rabbit model

The purpose of this study was to examine the correlation of quantitative dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) with microvessel density (MVD) in necrotic, partial necrotic, and viable tumors using a rabbit VX2 liver tumor model. Nine rabbits were used for this study. The complete necrotic area (CNA), partial necrotic area (PNA), and viable tumor area (VTA) of liver tumors were experimentally induced by radiofrequency ablation (RFA). DCE-MRI data were processed based on the extended Kety model to estimate K^trans, v_e and v_p parameters. The boundaries among CNA, PNA, and VTA were delineated based on H&E stain images, and MVD was assessed for each subregion of each VX2 tumor based. There were no correlations between ph-parameters (K^trans, v_e, and v_p) and MVD for CNA. For PNA, the K^trans values were positively correlated with the MVD (r = 0.8124, p < 0.001). For VTA, we found a positive correlation between K^trans values and the MVD (r = 0.5743, p < 0.05). Measuring from both the PNA and the VTA, mean K^trans values were positively correlated with mean MVD (r = 0.8470, p < 0.0001). In a rabbit VX2 liver tumor model, K^trans values correlated well with MVD counts of PNA and VTA in liver tumors.