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- Imaging
- • Barium enema x-ray.
- • Ultrasound of the abdomen and, perhaps, within the rectum. Endorectal ultrasonography can accurately show
- tumor invasion and enlarged lymph nodes outside the rectum, but cannot indicate if enlarged lymph nodes
- actually contain metastatic tumor.
- • Abdominal CT and MRI scans to identify distant metastases before surgery.
- • Chest x-ray may reveal lung metastases.
- • PET (positron emission tomography) scanning, (experimental), can help assess the early response of liver
- metastases to chemotherapy by showing changes in sugar metabolism.
- • Radioimaging body scan before surgery with CYT-103 monoclonal radiolabeled indium antibodies may help
- detect hidden metastatic disease in about 12 percent of cases. This experimental method can complement CT
- scans, increasing their diagnostic sensitivity for finding hidden metastatic sites in the pelvis and other areas
- outside the liver. Other monoclonal antibody and imaging tests are being developed. Current monoclonal
- antibody scans are not completely reliable in the detection of liver metastases.
- Studies with anti-CEA monoclonal antibodies have shown a high accuracy in detecting tumors smaller than 1
- cm (¬Ω in.). This may be helpful to the surgeon. The usefulness of these radioisotope scans is not yet certain.