The value of multi-parameter diffusion and perfusion magnetic resonance imaging for evaluating epithelial-mesenchymal transition in rectal cancer

Purpose Epithelial-mesenchymal transition (EMT) is characterized by a decreased expression of E-cadherin and an increased expression of vimentin, which is associated with poor prognosis in rectal cancer. This study aimed to explore the feasibility of using multi-parameter diffusion and perfusion magnetic resonance imaging (MRI) to evaluate the expression of E-cadherin and vimentin. Methods One hundred and ten patients with rectal cancer, who underwent preoperative multi-parameter diffusion and perfusion MRI and subsequent radical resection of rectal carcinoma, were included in this prospective study. The expression of E-cadherin, vimentin, vascular endothelial growth factor (VEGF), and Ki67 was identified by immunohistochemical test and MRI morphology features; quantitative parameters were analyzed and combined diagnostic models were created by binary logistic regression. The receiver operating characteristics curve with area under the curve (AUC) was used to evaluated diagnostic performance. Interobserver agreement for MRI parameters was evaluated by intraclass correlation coefficient. Results In the low expression E-cadherin group, the VEGF expression was significantly higher than the high expression group (60.5% vs 37.3%, P < 0.05), and the Ki67 expression had no significant difference (P > 0.05). In the high expression vimentin group, the Ki67 expression was significantly higher than the low expression group (77.3% vs 56.1%, P < 0.05), and the VEGF expression was not significantly significant (P > 0.05). MRI morphological features had no significant diagnostic efficacy for E-cadherin and vimentin expression in rectal cancer (P > 0.05). There were positive and negative correlations between apparent diffusion coefficient (ADC) values with E-cadherin and vimentin expression (P < 0.05), the Ktrans and Kep values were negatively and positively correlated with the expression of E-cadherin and vimentin (P < 0.05). The ADC value (b = 3000 s/mm2) had mild significant diagnostic efficiencies for low E-cadherin expression and high vimentin expression (AUC = 0.63 and 0.644, P < 0.05), the Ktrans and Kep values had significant diagnostic efficiencies (AUC = 0.801 and 0.724, P < 0.05; AUC = 0.722 and 0.628, P < 0.05, respectively). The combined model of ADC, Ktrans, and Kep values had good diagnostic efficiencies for low E-cadherin expression and high vimentin expression (AUC = 0.814 and 0.728, P < 0.05). Conclusion The quantitative parameters of diffusion (with ultra-high b-values) and perfusion MRI can assess the major biomarkers of EMT in rectal cancer, and the combined diagnostic model could further improve the evaluating efficiency for EMT, which possibly can provide valuable information for non-invasive and preoperative assessment of the tumor microenvironment.