In rectal cancer, MSCT of the rectum and anal canal can predict the stage preoperatively, but the final determination depends upon pathology examination of the resected tumor and adjacent lymph nodes (pathologic stage).MSCT is valuable in staging rectal cancer and is used to classify the T, N and M stage of rectal cancers. MSCT colonography is an excellent tool in detection of ascites and distant metastases especially in liver and it also allows simultaneous assessment of colonic mucosal surface by producing cross-sectional and endoluminal images of the colon, but it is not valuable enough in assessment of depth of wall invasion, pericolic lymph nodes involvement, surrounding structures invasion and relation to the anal sphincters which affect the outcome of surgery preoperative planning for neoadjuvant chemoradiation therapy.