Objectives: To evaluate the role of CT scan in preoperative staging of colorectal carcinoma by comparing it with the surgical-pathologic staging and pathologic findings.
Material and Method: The CT scans of twenty four patients with pathological proven primary colorectal carcinoma from January 1998 to December 2002 at Srinagarind hospital Khon Kaen University were review. The CT findings were analyzed according to serosal and or pericolic fat invasion, involvement of lymphnodes, liver or other metastases, and correlated the CT staging with TNM staging.
Results: The CT imaging had 100% sensitivity, 57% specificity, 87.5% accuracy for evaluating serosal and/or pericolic fat invasion, 93.2% sensitivity, 54% specificity, 75% accuracy for evaluating involvement of the lymph nodes. In the present study, the distant metastases was not detected.
Conclusion: The role of CT in preoperative staging of colorectal carcinoma in this report can be summarized as: (1) The sensitivity in detecting serosal and/or pericolic fat invasion is relatively higher than in previous reports. (2) The criteria for evaluation of nodal disease increased accuracy of CT, and its high sensitivity is considered clinically useful.

Keywords: Colorectal carcinoma, CT staging