[Supplement of CT evaluation on staging of rectal carcinoma]

Preoperative pelvic computed tomographic (CT) images were analyzed in 50 patients with rectal carcinoma to evaluate the depth of mural invasion. Firstly the rectum was inflated with air. Secondly cross-sectional CT images of the rectal carcinoma were taken, in all cases referring to lateral scout view films and barium enema films. The circle rate of the tumor was determined in the cross-sectional image. Perirectal changes on CT were evaluated where there were spiculated and nodular appearances. The circle rate correlated with the extent of mural invasion. In cases within 1/3 circle in the circle rate and without perirectal nodular appearance, more than 90% of the tumors were limited to the muscularis propria of the rectal wall. These findings were very useful for assessing suitable surgical treatment.