Purpose:To evaluate multi-parametric MRI features in predicting pathological response after preoperative chemo-radiation therapy (CRT) for locally advanced rectal cancer (LARC). Experimental Design: Forty-eight consecutive patients (01/2012-11/2014) receiving neoadjuvant CRT were enrolled. All underwent anatomical T1/T2, Diffusion-Weighted-MRI(DWI) and Dynamic-Contrast-Enhanced(DCE)-MRI before CRT. A total of 103 imaging features, analyzed using both volume-averaged and voxelized methods, were extracted for each patient. Univariate analyses were performed to evaluate the capability of each individual parameter in predicting pathological-complete-response (pCR) or good-response (GR) evaluated based on tumor regression grade (TRG). Artificial neural network (ANN) with 4-fold validation technique was further utilized to select the best predictor sets to classify different response groups and the predictive performance was calculated using receiver operating characteristic (ROC) curves. Results:The conventional volume-averaged analysis could provide an area under ROC curve (AUC) ranging from 0.54-0.73 in predicting pCR. While if the models were replaced by voxelized heterogeneity analysis, the prediction accuracy measured by AUC could be improved to 0.71-0.79. Similar results were found for GR prediction. In addition, each sub-category images could generate moderate power in predicting the response, which if combining all information together, the AUC could be further improved to 0.84 for pCR and 0.89 for GR prediction, respectively. Conclusions:Through a systematic analysis of multi-parametric MR imaging features, we are able to build models with improved predictive value over conventional imaging metrics. The results are encouraging, suggesting the wealth of imaging radiomics should be further explored to help tailoring the treatment into the era of personalized medicine.
- Received December 16, 2015.
- Revision received May 6, 2016.
- Accepted May 7, 2016.
- Copyright ©2016, American Association for Cancer Research.