Magnetic Resonance Imaging of Rectal Cancer

High-resolution magnetic resonance imaging (MRI) plays a pivotal role in the pretreatment assessment of primary rectal cancer. The success of this technique depends on obtaining good-quality high-resolution T2-weighted images of the primary tumor, orthogonal to rectal lumen. The goal of magnetic resonance staging is to identify patients who will benefit from neoadjuvant therapy prior to surgery to minimize postoperative recurrence and planning of optimal surgical approach. MRI also facilitates optimal identification of important prognostic factors, which improves both treatment selection and posttreatment follow-up. The objective of this article is to review the existing literature and provide a concise update on various aspects of rectal cancer imaging, discuss the current role of advanced imaging techniques such as diffusion-weighted and perfusion imaging in the evaluation of rectal cancer, and to assess response to therapy.