Clinical significance of magnetic resonance imaging findings in rectal cancer

Staging of rectal cancer is essential to help guide clinicians to decide upon the correct type of surgery and determine whether or not neoadjuvant therapy is indicated. Magnetic resonance imaging (MRI) is currently one of the most accurate modalities on which to base treatment decisions for patients with rectal cancer. MRI can accurately detect the mesorectal fascia, assess the invasion of the mesorectum or surrounding organs and predict the circumferential resection margin. Although nodal disease remains a difficult radiological diagnosis, new lymphographic agents and diffusion weighted imaging may allow identification of metastatic nodes by criteria other then size. In light of this, we have reviewed the literature on the accuracy of specific MRI findings for staging the local extent of primary rectal cancer. The aim of this review is to establish a correlation between MRI findings, prognosis, and available treatment options.