DWI combined with standard T2WI for judging local recurrence of rectal cancer
Objective To observe the application value of MR DWI combined with standard T2WI in the judgment of local recurrence of rectal cancer.Methods Totally 325postoperative rectal cancer patients underwent MR examination including axial,coronal,sagittal T2Wand axial DWI sequence(b=0,1000s/mm2),and postoperative pelvic abnormalities were detected in 89patients.Two radiologists(observer 1,observer 2)used 2methods(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 29patients(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 2radiologists using DWI+T2WI were larger than that using only T2WI(observer 1:0.907vs 0.856;observer 2:0.882vs 0.823).The inter-observer agreement of 2observers 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.