MRI and its importance in rectal cancer.

Abstract

The potential value of thin slice, high resolution MRI of the pelvis is in assessing the important surgical prognostic risk factors. In the local staging of rectal cancer high resolution MRI should not only be used to predict the T stage but assessment should also include the depth of extramural spread of tumour, the relationship of the tumour to the peritoneal reflection and to the anal sphincter complex, the relationship between the outermost extension of the tumour and the mesorectal fascia, the presence and location of mesorectal deposits and identification of other prognostic factors such as extramural venous invasion and peritoneal invasion. Preoperative identification of patients with adverse prognostic features may allow targeting of such patients for the most appropriate preoperative adjuvant therapy, assist in surgical planning and serve as an accurate baseline study from which to assess the success of different treatment strategies.