Colorectal carcinoma: a radiologic and clinical review.

A profusion of imaging techniques is currently used for evaluating patients with suspected or known colorectal carcinoma. In most institutions, the combination of flexible sigmoidoscopy and a well-performed barium enema study should be retained as a more cost-effective, safe, and complete method of examination than colonoscopy. Endosonography appears to be promising for evaluating preoperatively the local extent of rectal carcinoma. CT is being challenged by MR imaging as the most sensitive modality for detecting liver metastases, but CT currently remains the technique of choice for evaluating recurrent disease and its extent. The diversity of available modalities will ensure that the radiologist remains at the forefront in the clinical investigation of colorectal carcinoma.