The clinical significance of CT in the preoperative diagnosis of colon and rectal cancer was studied. Thirty four patients were investigated in this series. The diagnostic criteria of the CT examination were previously established in a study of wall invasion (S factor), lymph node metastasis (N factor), liver metastasis (H factor) and peritoneal dissemination (P factor). The CT diagnosis was done prospectively according to these criteria, and the CT diagnosis was compared with the macroscopic and histological diagnosis.
The accuracy of the prospective diagnosis as to H, S, N and P factors was 79.4%, 55.9%, 41.2% and 20.6%, respectively. The diagnostic value of CT seemed to be acceptable as to the H factor, but limited to some extent to the S and N factors.