磁共振扩散加权成像对直肠癌新辅助治疗后病理完全缓解的预测价值

Clinical value of MR diffusion weighted imaging in prediction of pathological complete response of rectal cancer after neoadjuvant therapy

目的探讨磁共振扩散加权成像（DWI）结合常规T2WI序列对直肠癌新辅助治疗后病理完全缓解（pCR）的预测价值。方法回顾性分析2012年6月至2013年4月间在中山大学附属第六医院直肠癌诊疗中心接受新辅助治疗加根治性切除术的51例局部进展期中低位直肠癌患者的临床资料。所有患者均于新辅助治疗前1周内和术前1周内行磁共振DWI和T2WI两种序列扫描成像，分别采用T2WI序列和DWI结合T2WI序列两种方法主观评价肿瘤有无残留，并与术后病理结果对照，比较两种方法对pCR的预测价值。结果51例患者中12例（23．5％）获得pCR。DWI结合T2WI序列正确预测pCR8例，其预测敏感性和特异性分别为66．7％（8／12）和94．9％（37／39）；单独采用T2WI序列正确预测pCR4例，其预测敏感性和特异性分别为33．3％（4／12）和84．6％（33／39）；前者对pCR的预测价值明显高于后者（曲线下面积分别为0．808和0．590，P=0．001）。结论与单独应用T2WI序列相比。DWI结合T2WI序列能更加准确地对pCR进行预测。

Objective To evaluate the application value of magnetic resonance diffusion- weighted imaging （DWI） combined with routine T2WI sequence in the determination of pathological complete response（pCR） after neoadjuvant therapy for rectal cancer. Methods Clinical data of 51 cases with locally advanced mid-low rectal cancer undergoing neoadjuvant therapy plus radical resection in the Rectal Cancer Center at The Sixth Affiliated Hospital of Sun Yat-sen University from June 2012 to April 2013 were analyzed retrospectively. Magnetic resonance DWI and T2WI sequences scanning were performed within 1 week before neoadjuvant therapy and within 1 week before operation. Routine single T2WI sequence and DWI combined with T2WI sequence were used separately to predict the residual tumor and to compare with postoperative pathological examination. The prediction values of two methods were compared. Results Of 51 patients, 12 cases had pathological complete response（pCR）. Prediction of DWI combined T2WI sequence was correct in 8 cases of pCR, whose sensitivity and specificity were higher than those of routine single T2WI sequence （66.7%, 94.9% vs. 33.3%, 84.6%）. Prediction value of DWI combined T2WI sequence for pCR was significantly higher as compared to routine single T2WIsequence （AUC, 0.808 vs. 0.590, P=0.001）. Conclusion Compared with the routine single T2WI sequence, DWI combined with T2WI sequence can improve the prediction accuracy of pathological complete response.