MRI of rectal carcinoma: Preoperative staging and planning of sphincter-sparing surgery

BackgroundRectal cancer constitutes about one-third of all gastrointestinal tract tumors. Because of its high recurrence rates reaching 30%, it is vitally important to accurately stage these tumors preoperatively, so that appropriate surgical resection can be undertaken. MRI is used to assist in staging, identifying patients who may benefit from preoperative chemotherapy–radiation therapy, and in surgical planning.AimTo determine the accuracy of MRI in the preoperative staging and planning of surgical management of rectal carcinoma.Subjects and methodsTwenty-five patients (14 males, 11 females) with rectal carcinoma were included in this study. MRI scans were performed prior to surgery in all patients, on a 1.5T scanner, and images were evaluated by three experienced radiologists. Inter-observer agreement between the three radiologists and the correlation between the imaging findings, histopathology and operative findings were evaluated.ResultsMRI findings were correctly predictive of T category in 21 cases (accuracy, 84%). In 19 (86.4%) of the 22 resectable cases, sphincter-sparing surgical approaches were accurately chosen on the basis of MRI findings.ConclusionMRI of rectal cancer is accurate for prediction of tumor stage and the feasibility of sphincter-sparing surgery, which are the main factors affecting the outcome of surgery.