[Preliminary study of semi-quantitative and quantitative dynamic contrast-enhanced MRI in evaluating the response to...

To investigate the capability of semi-quantitative and quantitative parameters of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) to predict the response to concurrent chemoradiotherapy( CCRT) in patients with non-small cell lung cancer (NSCLC).

A total of 24 patients with stage III or IIIB NSCLC, who underwent 3.0T DCE-MRI before CCRT, were enrolled in this study. Semi-quantitative and quantitative parameters were calculated by Funtool and Omnikinetics software. The relationship between these obtained parameters and tumor response was evaluated by Spearmen' s correlation analysis. The patients were classified into two groups according to the tumor regression rate after treatment, as response group (group A) and non-response group ( group B). Mann-Whitney U test was used to compare the parameters of responders and non-responders. The value of the parameters on predicting response was calculated by receiver operating characteristic curve (ROC).

The tumor regression rate after treatment was negatively correlated with time to peak (TTP) and the extravascular-extracellular volume fraction (Ve), and was positively correlated with signal enhancement ratio (SERmax) and volume transfer constant (Ktrans) (P < 0.05 for all). Statistical significant differences were found between group A and group B both in semi-quantitative and quantitative parameters (P < 0.05). Group A had a lower TTP value [(34.66 ± 16.37) s vs. (44.09 ± 17.41) s] and Ve value [(0.19 ± 0.03) vs. (0.25 ± 0.05)] than group B, whereas group A had a higher SERmax [(166.50 ± 44.95)% vs. (113.57 ± 46.62)%] and Ktrans [(0.41 ± 0.17) min(-1) vs. (0.28 ± 0.12) min(-1)] than group B (P < 0.05 for all). The ROC analysis indicated that when setting the threshold of Ve on ≤ 0.21 for predicting response, the specificity, sensitivity and accuracy were 85.7%, 80.0% and 83.3%, respectively, with an area under curve of 0.875 (P < 0.001).

Both the semi-quantitative and quantitative DCE-MRI parameters are helpful for predicting the response after CCRT of NSCLC. Quantitative parameters seem to be more meaningful than semi-quantitative parameters.