Perfusion Parameters of Dynamic Contrast-Enhanced Magnetic Resonance Imaging in Patients with Rectal Cancer: Correlation with Microvascular Density and Vascular Endothelial Growth Factor Expression

Objective: To determine whether quantitative perfusion parameters of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) correlate with immunohistochemical markers of angiogenesis in rectal cancer. Materials and Methods: Preoperative DCE-MRI was performed in 63 patients with rectal adenocarcinoma. Transendothelial volume transfer ($K^{trans}$) and fractional volume of the extravascular-extracellular space (Ve) were measured by Interactive Data Language software in rectal cancer. After surgery, microvessel density (MVD) and vascular endothelial growth factor (VEGF) expression scores were determined using immunohistochemical staining of rectal cancer specimens. Perfusion parameters ($K^{trans}$, Ve) of DCE-MRI in rectal cancer were found to be correlated with MVD and VEGF expression scores by Spearman's rank coefficient analysis. T stage and N stage (negative or positive) were correlated with perfusion parameters and MVD. Results: Significant correlation was not found between any DCE-MRI perfusion parameters and MVD (rs = -0.056 and p = 0.662 for $K^{trans}$; rs = -0.103 and p = 0.416 for Ve), or between any DCE-MRI perfusion parameters and the VEGF expression score (rs = -0.042, p = 0.741 for $K^{trans}$; r = 0.086, p = 0.497 for Ve) in rectal cancer. TN stage showed no significant correlation with perfusion parameters or MVD (p > 0.05 for all). Conclusion: DCE-MRI perfusion parameters, $K^{trans}$ and Ve, correlated poorly with MVD and VEGF expression scores in rectal cancer, suggesting that these parameters do not simply denote static histological vascular properties.