磁共振DWI结合标准T2WI判断直肠癌局部复发

DWI combined with standard T2WI for judging local recurrence of rectal cancer

目的评价MR DWI结合标准T2WI判断直肠癌局部复发的价值。方法对325例直肠癌患者术后随访期间均行MR轴位、冠状位、矢状位T2W和轴位DWI(b=0、1000s/mm2);其中89例存在盆腔异常表现,2名医师(观察者1、2)分别采用两种方法(T2WI、DWI+T2WI)进行阅片,探讨DWI+T2WI对直肠癌局部复发的诊断效能。结果 89例盆腔局部异常表现患者中,32.58%(29/89)为直肠癌局部复发。2名医师单独采用T2WI判断局部复发的准确率分别为85.39%(76/89)、80.90%(72/89);采用DWI+T2WI的准确率分别达91.01%(81/89)、87.64%(78/89)。DWI+T2WI的ROC曲线下面积均高于T2WI(观察者1:0.907vs 0.856;观察者2:0.882vs 0.823)。采用T2WI时,2名阅片者的一致性良好(Kappa=0.674);采用DWI+T2WI时,一致性非常好(Kappa=0.831)。结论标准T2WI诊断直肠癌术后局部复发的准确率较高,结合DWI可进一步提高诊断效能。

Objective To observe the application value of MR DWI combined with standard T2WI in the judgment of local recurrence of rectal cancer. Methods Totally 325 postoperative rectal cancer patients underwent MR examination including axial, coronal, sagittal T2W and axial DWI sequence （b=0, 1000 s/mm2）, and postoperative pelvic abnormalities were detected in 89 patients. Two radiologists （observer 1, observer 2） used 2 methods （T2WI, DWI＋T2WI） to observe the images, and the value of DWI＋T2WI in diagnosis of local recurrence were assessed. Results Among patients with postoperative pelvic abnormalities, local recurrence of rectal cancer was proved in 29 patients （29/89, 32.58%） . The accuracy of 2 radiologists were 85.39% （76/89） and 80.90% （72/89） using only T2WI, 91.01% （81/89） and 87.64% （78/89） using DWI＋T2WI, respectively. Areas under ROC curve of 2 radiologists using DWI＋T2WI were larger than that using only T2WI （observer 1：0.907 vs 0.856; observer 2： 0.882 vs 0.823）. The inter-observer agreement of 2 observers for T2WI was good （Kappa=0.674）, while it was excellent （Kappa=0.831） of T2WI combined with DWI. Conclusion Standard T2WI has high diagnostic accuracy for locally recurrent rectal cancer, which can be improved when combining with DWI.