CT VS MRI IN DIAGNOSIS OF RECURRENT RECTOSIGMOID CARCINOMA

Objective: Our goal was to compare the relative values of MRI vs. CT i n diagnosing recurrent rectosigmoid cancer. Materials and Methods: We conducted a retrospective review of 18 patients who had surgical resec tion of primary rectosigmoid carcinoma and suspected recurrence. They were studied with CT and MR and followed for up to 4 years. Results: A t the time of the initial imaging, 10 patients had recurrent tumor and 4 of the remaining 8 patients later demonstrated local recurrence. Ma gnetic resonance demonstrated 91% sensitivity, 100% specificity, a pos itive predictive value (PPV) of 100%, and a negative predictive value (NPC) 89% with a 95% accuracy. Computed tomography demonstrated a sens itivity of 82% and a specificity of 50% with a PPV of 69%. In three ca ses interpreted on CT as presacral masses, all were shown on MR to rep resent displaced but normal pelvic structures. In four cases MR reveal ed tumor involving the sacrum and sacral nerves not apparent on CT. Co nclusion: Magnetic resonance showed superior sensitivity, specificity, and accuracy to CT and better definition of the extent of tumor.