Progress in radiology: colorectal tumors: pathology and detection.

The prognosis in colorectal neoplasia has not improved in the past 20 years despite improved diagnostic techniques. The greatest promise lies in wider screening and earlier radiographic and endoscopic detection. To clarify the radiologist's role in finding large bowel tumors, the clinical, pathologic, and radiologic literature is reviewed. Since individuals over 40 years of age harbor the bulk of colon neoplasms, the most diligent efforts to detect these lesions should be made in this group. Controlled studies comparing single and double contrast barium enema techniques are lacking, but available data suggest that the double contrast examination is more sensitive for detection of the numerous small, but potentially malignant colon tumors. Careful radiographic technique, including a thoroughly clean colon, is critical for accurate detection regardless of which technique is used.