The accuracy of High Resolution Magnetic Resonance in local staging of rectal cancer

Objective: To assess the accuracy of preoperative staging of rectal cancer with magnetic resonance imaging (MRI) and illustrate the correlation of MR imaging with pathologic findings and clinical impact of MR imaging in this setting. Methods: Total of 447 patients with rectal cancer between 01.04.2009-31.03.2010 underwent MRI in our department. 76 patients with suspected or confirmed rectal carcinoma had preoperative staging examination. Rectal cancer imaging protocol included T2weighted imaging in the sagittal, coronal and axial planes alongside a high-resolution plane perpendicular to the rectum at the level of primary tumor, and fat suppressed contrast-enhanced MRI was performed. Histopathological results were used as gold standard. Results: Rectal carcinoma was identified on MRI and confirmed histological in 24 patients. MRI findings were correctly of T category in T1 1/6 cases, in T2 4/9, T3 8/9, T4 5/6 cases. Accuracy was 70% Conclusion: Comparing pretreatment MRI staging and post therapy histology assessment we concluded that high resolution MR (HRMR) is an accurate technique for prediction of rectal tumor stage. It allows identification of patients with extrarectal spread, who might benefit from preoperative radiation therapy and patients with minimal or no sphincteral involvement, who might be suitable for sphincter sparing surgery.