New imaging modalities for follow-up of colorectal carcinoma.

Recurrent disease after curative resection occurred in 37-44% of patients. The common sites of recurrent disease are at the anastomotic site, in the liver, in the lymph nodes, and in the peritoneal linings. Computed tomography (CT), barium enema, and endoscopy detected local recurrent disease in 61-88% of the patients, whereas magnetic resonance imaging (MRI) detected 80-88% of the cases reported in some Phase 1 studies. CT and MRI are equally effective in the detection of hepatic metastases when lesions are larger than 2 cm, with detectability rate of 95-100%. They are fair (50-60% detectability rate) when tumors are between 1 and 2 cm and poor (less than 40%) when tumors are smaller than 1 cm. For recurrent nodal metastases and peritoneal deposits, CT is the modality of choice.