Rectal MR Imaging.

MR imaging comprising high-resolution T2-weighted imaging and high b value diffusion-weighted imaging has proven effective in guiding treatment selection and preoperative planning for rectal cancer. In addition to staging, it enables the noninvasive assessment of key bioimaging markers such as extramural vascular invasion, tumor deposits, and the presence and location of mesorectal fascia and anal sphincter involvement. After neoadjuvant therapy, MR imaging offers noninvasive treatment response, complementing endoscopic and digital rectal evaluations. This assessment plays a crucial role in determining the feasibility of organ preservation or watch-and-wait strategy in patients who achieve complete clinical response.