Role of endorectal coil magnetic resonance imaging in local staging of rectal cancer: Experience from a single center

Purpose: In order to obtain an improvement in preoperative staging accuracy for rectal cancer, new imaging modalities are now under investigation. The purpose of our study was to evaluate the accuracy of endorectal coil magnetic resonance imaging (ECMRI) in the preoperative local staging of rectal cancer and correlation with intraoperative and histopathologic staging of retrieved specimen with respect to depth of tumor invasion and lymph node metastasis. Materials and Methods: The study was a prospective one and included 38 patients with biopsy proved rectal cancer. ECMRI studies were performed on a 1.5 Tesla MR unit using a standard endorectal coil. All patients underwent surgery and a comparative evaluation of ECMRI and surgical and pathological staging was done. Accuracy, sensitivity, specificity, and positive and negative predictive value (PPV and NPV) were assessed. Results: The diagnostic accuracy of ECMRI for T1/T2 tumors was 90%; for T3 and T4 tumors accuracy was 100% each. For perirectal lymph node metastasis, the diagnostic accuracy of ECMRI was 83.3%. Conclusion: ECMRI is a reliable radiologic tool for local (T) staging of rectal cancer and has excellent diagnostic accuracy, sensitivity, and specificity. ECMRI is also useful in detecting perirectal lymph node metastasis, but accuracy is not as good as that for T staging.