E2728. Rectal MRI: A Review of Primary Staging and Posttreatment Imaging of Rectal Cancer
  1. Hala Khasawneh; Memorial Sloan Kettering Cancer Center
  2. Kevin Chang; Boston Medical Center
  3. Natally Horvat; Memorial Sloan Kettering Cancer Center
  4. Zahra Kassam; St Joseph's Health Care London
  5. Gaurav Khatri; UT Southwestern Medical Center
  6. Ashish Wasnik; University of Michigan
  7. Maria El Homsi; Memorial Sloan Kettering Cancer Center
Rectal MRI plays an important role in guiding multidisciplinary teams in treatment planning. It has a key role in primary staging of rectal cancer and post-treatment evaluation. It is essential for the radiologist to be aware of how to acquire high quality MRI scan. Moreover, a radiologist’s knowledge about the relevant anatomy in the pelvis is crucial to determine disease extent and invasion to pelvis structures. The current management is guided by rectal MRI reports including the local extent of the disease. We will provide a brief review of what a radiologist needs to know about current surgical and treatment management for patients with rectal cancer.

Educational Goals / Teaching Points
Using a case-based approach we will reinforce the role of MRI in patient’s diagnosis and management of patients with rectal cancer. The exhibit will include the role of MRI in primary staging, including rectal tumor location and morphology assessment, the relationship of tumor and with surrounding pelvic structures (involvement of anal canal, Circumferential Resection Margin (CRM), tumor invasion of adjacent organs, Extramural Vascular Invasion (EMVI). The role of functional sequence particularly Diffusion Weighted Images (DWI). Through follow-up cases, we will give an overview of MRI in restaging patients with rectal cancer. By emphasizing the role of T2W and DWI and discussing the assessment for complete versus partial response rectal tumors or tumor progression. Lastly, we aim to highlight the cases with mucin development posttreatment. We will discuss relevant lymph nodes assessment in the setting of rectal cancer by describing the imaging criteria for TME and extra-TME nodes in both, primary staging and treatment response. Finally, a brief overview of distant metastases imaging.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
Overview of relevant MRI anatomy of the pelvis and an overview of MRI imaging technique and protocol to acquire dedicated rectal MRI .

Rectal MRI is essential in staging and restaging of patients with rectal cancer as it plays a pivotal role in guiding management.