Objective To study the value of multi-slice spiral CT(MSCT)and high-resolution MR in evaluating the feasibility of total mesorectal excision(TME)for rectal cancer before operation.Methods Sixty-three cases biopsy-proven rectal cancer underwent MSCT and high-resolution MR examination,including CT in 35 and MR in 28.The involvement of mesorectal fascia,lymph nodes extra-fascia and the curve distance between the lesions and the anal margin were observed and compared with that of operation and pathology.Results In evaluating the involvement of mesorectal fascia,two patients were oversteped by CT and one patient by MRI,and there was no significantly statistic difference between CT and MRI.The curve distance between lesions and anal margis could be measured accurately on sagittal section of MR images in all cases.Sixteen patients had been found having metastatic lymph nodes at extra-mesorectal fascia,twelve of them were biopsy-proven.Thirty-seven patients had been found having metastatic lymph nodes at intra-mesorectal fascia,but 4 of them were inflammatory biopsy-proven.Conclusion MSCT and high-resolution MR are of significant values in evaluating the feasibility of TME in the patients with rectal carcinoma.