To determine the prognostic value of dynamic contrast-enhanced MRI (DCE)and diffusion-weighed imaging (DWI) for stage Ⅲ non-small-cell lung cancer (NSCLC) treated with concurrent chemoradiotherapy(CRT).

55 stage III NSCLC patients treated with CRT underwent DCE and DWI . The patients were divided into two groups (local control (n=11) and local failure (n=44)). From the signal intensity-time course curve in each subject, the maximum enhancement ratio and slope of enhancement were calculated, while gained the apparent diffusion coefficients from DWI and compared between two groups by t test. To determine the feasible threshold values of both MR indexes for group differentiation, ROC-based positive tests were performed. 

The maximum enhancement ratio and the slope of enhancement in the local control group were significantly lower than those in the local failure one (P =0.017, 0.033). The apparent diffusion coefficients in the local control group were significantly higher than those in the local failure one (P =0.017, 0.003). Using 0.028/sec as the threshold value of the slope of enhancement, the sensitivity and specificity for differentiation between the two groups were 90.9% and 93.2%, respectively. When the slope of enhancement was adopted for estimation of prognosis after therapy, the mean survival period of the slope of enhancement ≥ 0.028/sec group was significantly longer than that seen in the other group(P =0.009). Using 1.676×10^-3mm²/s as the threshold value of the apparent diffusion coefficients (b=300s/ mm²), the sensitivity and specificity for differentiation between the two groups were 90.9% and 93.2%, respectively. When the apparent diffusion coefficients (b=300s/ mm²) was adopted for estimation of prognosis after therapy, the mean survival period of the apparent diffusion coefficients < 1.676×10^-3mm²/s group was significantly longer than that seen in the other group (P =0.033).

DCE and DWI may be as a prognostic factor for patients with stage III NSCLC undergone CRT.