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

Abstract

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. J. Magn. Reson. Imaging 2005;21:775–783.