CT - Colonography. English.

Colonoscopy has been the diagnostic procedure of choice for examining the colon and rectum for many years, although it is well known that detection rates of significant pathology are operator dependent. Cecal acces rates may vary between experienced endoscopists and depend on various factors, with inadequate bowel preparation, anatomic variants, fixed colon segment, obstructing lesions, being a few of the possible reasons for incomplete colonoscopy. A generally accepted rule, however, is that each endoscopist should be able to intubate the cecum in at least 90% of colonoscopies. A recent study showed that advanced neoplasia can be missed in up to 4.3% of patients during incomplete colonoscopy, suggesting that further colonic evaluation is mandatory in these cases. One of the suggested options is to refer a patient for a second procedure to a skilled endoscopist with a known high colonoscopic success rate. A repeat colonoscopy on a different occasion, however, has the disadvantage of a repeat, bowel preparation with the risk of a second procedure failure. Several radiological modalities are available to visualize the colon. Double-contrast barium enema has traditionally been the procedure of choice after incomplete colonoscopy. It has a high success rate (>99%) for visualizing the entire colon. In recent years, computed tomography- colonography (CTC) has emerged as an alternative modality to visualize the colonic lumen. Although relatively new, it is a diagnostic modality with proven good results for detecting polyps with a size of 5 mm or larger and has been suggested to be a promising screening modality for colorectal cancer (CRC). In addition, it can be used to investigate the colon in patients in whom colonoscopy is contraindicated. The fact that both intracolonic and extracolonic lesions can be visualized may make this modality attractive in patients with symptoms that possibly, but not definitely, originate from the colon. All patients underwent CTC with intravenous contrast, conceivably adding to the interpretability of the extracolonic tissues. This may also explain our relatively low yield of undetermined incidental findings necessitating further diagnostic evaluation. In case of extracolonic findings, the radiologist was, in most cases, sufficiently confident with regard to the diagnosis to refrain from advising additional investigations. The final evidence for the added value of CTC after incomplete colonoscopy, if indeed required, should come from a randomized trial in which CTC is compared with repeat colonoscopy performed by another (expert) endoscopist for relevant findings, quality of life and acceptance of patients, and cost-effectiveness.