Prognostic value of dynamic MR imaging for non-small-cell lung cancer patients after chemoradiotherapy

Purpose: To determine the prognostic value of dynamic MRI for non-small-cell lung cancer (NSCLC) patients after chemoradiotherapy. Materials and Methods: A total of 114 consecutive patients with NSCLC underwent dynamic MRI after chemoradiotherapy. The patients were divided into two groups (local control (n = 22) and local failure (n = 92)) according to the presence of local recurrence. From the signal intensity-time course curve in each subject, the maximum relative enhancement ratio and slope of enhancement were calculated, and compared between two groups by Student's t-test. To determine the feasible threshold values of both MR indexes for group differentiation, ROC-based positive tests were performed. Finally, the Kaplan-Meier survival curves of each group divided by the adapted threshold value were compared by log-rank test. Results: The maximum relative enhancement ratio and the slope of enhancement in the local control group were significantly lower than those in the local failure group (P < 0.05). Using 0.08/sec as the threshold value of the slope of enhancement, the sensitivity and specificity for differentiation between the two groups were 90.9% and 91.3%, respectively. When the slope of enhancement was adopted for estimation of prognosis after therapy, the mean survival period of the slope of enhancement ≤ 0.08/sec group was significantly longer than that seen in the group with a slope of enhancement > 0.08/sec (P < 0.0001). Conclusion: Dynamic MRI has potential prognostic value for NSCLC patients after chemoradiotherapy.