Association between high-resolution MRI-detected extramural vascular invasion and tumour microcirculation estimated by dynamic contrast-enhanced MRI in rectal cancer: preliminary results

BackgroundTo determine whether magnetic resonance imaging (MRI)-detected extramural vascular invasion (mrEMVI) status is associated with quantitative perfusion parameters derived from dynamic contrast-enhanced MRI (DCE-MRI) in rectal cancer.MethodsSeventy-two patients with rectal adenocarcinoma who underwent curative surgery alone within 2weeks following rectal MRI were enrolled in this retrospective study. mrEMVI status was determined based on high-resolution MRI. The quantitative perfusion parameters (K-trans, k(ep) and v(e)) derived from DCE-MRI were calculated from all sections containing tumours. DCE-MRI parameters and clinicopathological variables in patients with different mrEMVI statuses were compared.ResultsFor patients who were mrEMVI positive, the tumours demonstrated significantly lower k(ep) values (P=0.012) and higher v(e) values (P=0.021) than tumours of patients who were mrEMVI negative, while the K-trans value displayed no significant difference (P=0.390). The patients who were mrEMVI positive had larger tumour size, higher pathological tumour stage and increased regional nodal metastases compared to those who were mrEMVI negative (2.9cm vs. 3.5cm, P=0.011; 63.8% vs. 92.0%, P=0.010; 36.2% vs. 76.0%, P=0.001; respectively).ConclusionsThis study demonstrated for the first time that tumour microcirculation is altered in mrEMVI-positive patients with rectal adenocarcinoma, as evidenced by significantly lower k(ep) and higher v(e) values. In addition, these patients were more likely to have a larger tumour size, a higher pathological tumour stage and regional nodal metastases than mrEMVI-negative patients.