We propose to determine the sensitivity, specificity and diagnostic odds ratio (DOR) of magnetic resonance imaging (MRI) and computed tomography (CT) for detecting lymph node metastasis in patients with preoperative rectal cancer and specifically to determine which one is the optimal radiologic modality for the diagnosis of lymph node metastasis. We propose to identify the test which has the higher sensitivity and acceptable DOR as the optimal test.

We also plan to estimate the difference in diagnostic accuracy for lymph node metastasis between patients with and without preoperative chemotherapy and/or radiation therapy.