Perfusion parameters of dynamic contrast-enhanced magnetic resonance imaging in patients with rectal cancer: correlation with microvascular density and vascular endothelial growth factor expression

Abstract

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.

Keywords: Dynamic contrast-enhanced magnetic resonance imaging; MVD; Perfusion; Rectal cancer; VEGF.

Fig. 1

Dynamic contrast-enhanced magnetic resonance imaging image of pathologically T2N0 rectal cancer from 50-year-old woman. Three serial ROIs were drawn from three sections through tumor (A), and mean K^trans (1.174 min^-1) and Ve (0.209) were obtained (B). Histopathologic specimen of rectal adenocarcinoma showed (C) high MVD score (vascular endothelial cells shown in brown identify microvessels) and (D) strong VEGF expression (positive expression of VEGF is shown in brown in cytoplasm; 100 ×). Hot-spot MVD was 99.3 (mean number of microvessel/mm²), and VEGF expression score was 7. ROI = region of interest, MVD = microvessel density, VEGF = vascular endothelial growth factor

Fig. 2

Scattergram shows relationship between K^trans and MVD score (A) and between K^trans and VEGF score (B). K^trans value is not correlated with MVD and VEGF scores. MVD = microvessel density, VEGF = vascular endothelial growth factor