Value of magnetic resonance imaging in the preoperative TN staging of rectal cancer

Objective To assess the value of magnetic resonance imaging (MRI) in the preoperative TN staging of rectal cancer. Methods Between January 2006 and January 2007, 60 patients with rectal cancer completed preoperative MRI staging which were compared with pathologic staging and then the results were analyzed by means of Kappa statistics. Results The 60 patients were graded in T and N staging respectively. The sensitivity of MRI in detecting the bowel wall invasion was 77.8%, the specificity was 81.8%, and the accuracy was 80%. The sensitivity for the detection of malignant lymph nodes metastasis was 85.3%, the specificity was 69.2%, and the accuracy was 78.3%. Statistically, there was good correlation between pathologic and radiologic results of T staging (Kappa, 0.596) and N staging (Kappa, 0.553). Conclusions Preoperative MRI staging is able to detect the penetration of rectal cancer and metastasis of malignant lymph nodes, and therefore correctly predicts the staging of rectal cancer.