LOCAL STAGING OF RECTAL CANCER USING THE BLACK LUMEN MAGNETIC RESONANCE IMAGING TECHNIQUE

Background and Aims: The treatment of rectal cancer is comprised of surgery and possible adjuvant therapy depending on the stage of the tumour. This prospective study evaluates the accuracy of magnetic resonance imaging (MRI) in the preoperative staging of rectal cancer using an endorectal and intravenous contrast. Materials and Methods: 37 consecutive patients with rectal cancer were imaged using a mixture of ferumoxsil and methylcellulose endorectally, and a gadolinium contrast intravenously. 33 tumours were resected and 4 tumours were considered unresectable during operation. The images were reviewed for local staging of the tumours. A tumour confined to the rectal wall was classified as a negative finding and a tumour invading through muscularis propria as a positive finding. The results were correlated with the histopathologic T stage (n = 33), or the clinical status (n = 4). Results and Conclusions: Of 37 cases, 20 (51 %) were true positive, and 11 (28%) were true negative. There were 3 false negative and 3 false positive cases. The sensitivity was 87%, specificity 79%, and diagnostic accuracy 84%. For the non-contrast images the figures were 78%, 79% and 78%, respectively. We consider black lumen magnetic resonance imaging to be a useful method for preoperative local staging of rectal cancer.