Clinical Analysis On Diagnostic Value Of MRI In Preoperative T-stage Of Rectal Cancer

Objective: To evaluate the performance of MRI for assessingpreoperative T-stage of rectal cancer.Materials and methods: We retrospectively reviewed the relationshipbetween preoperative MRI T-stage and postoperative pathologicT-stage of75patients with diagnosis of primary rectal cancerconfirmed by pathology in China-Japan Union Hospital of JilinUniversity during October2012to September2013. There werealtogether51male cases and24females, aging from32to80yearsold, and the average is59.60. All patients were diagnosed withprimary rectal cancer by pathology, who later underwent MRIexaminations followed by surgery within1-4days afterwards. BeforeMRI examinations, no cases received preoperative chemoradiotherapyor any irritant physical examination. All the patients underwenttotal mesoretal excision(TME), including Dixon surgical approachand Miles surgical approach, and the surgical specimens were fixedby formalin within half an hour after excision when paraffinembedding took place and the specimens were cut into slices, HE staining afterwards. Finally the tissue slices were observed anddiagnosed under microscope by2independent experiencedpathologists, at the same time all MR images were analysed by twoexperienced radiologists respectively, and then TNM stagingconclusions were made. Pathologic staging was viewed as the goldstandard, which was compared with preoperative MRI staging tocalculate the accuracy, sensitivity, specific.Results: After the MRI examinations,2cases are diagnosed with T1stage,13cases are diagnosed with T2stage,55cases are diagnosedwith T3stage,5cases are diagnosed with T4stage; on the otherhand, pathologic staging shows that4cases are diagnosed with T1stage,18cases are diagnosed with T2stage,51cases are diagnosedwith T3stage,2cases are diagnosed with T4stage. The accuracyof the regular MRI sequence+DWI is76%in all. The sensitivitiesfrom T1to T4are50%,44.44%,88.24%and100%. The specificitiesfrom T1to T4are100%,91.23%,58.33%and95.89%. In all18misdiagnosed cases,15are overstaged which is83.33%and much morethan the understaged;13of all misdiagnosed cases are between T2and T3stages which is72.22%.Conclusion: The regular MRI sequence+DWI for evaluatingpreoperative T-stage of rectal cancer is of value.