The clinical availability of CT colonography

Computed tomographic (CT) colonography allows the visualization of extracolonic organs, thereby permitting the detection of potentially significant pathologies beyond the colon.

Extracolonic lesions are found in 15%-85% of cases, with some being important lesions, such as extracolonic cancer or aortic aneurysm. Early detection of extracolonic lesions is an aim of CT colonography. In particular, the detection of significant lesions is very important. However, the incidence rates of significant extracolonic lesions vary from country to country, and most reports relate to the Western population.

A research team led by Dr Dong Il Park from Korea determine the frequency and characteristics of extracolonic lesions detected using CT colonography. Their study will be published on March 28, 2009 in the World Journal of Gastroenterology.

Extracolonic lesions were divided into three categories, according to their significance. Highly significant lesions include those requiring immediate surgical therapy, medical intervention and/or further investigation. Lesions of intermediate significance include conditions that do not require immediate therapy but would likely require further investigation, recognition or therapy at a later time. Lesions of low significance include benign conditions that do not require further medical therapy or additional work-up.

A total of 920 consecutive subjects (men/women = 535/385) were analyzed. Six hundred and ninety two extracolonic findings were found in 532 (57.8%) subjects, and 60 (8.7%) highly significant, 250 (36.1%) intermediate significant and 382 (55.2%) low significant lesions were detected. When factors related to the clinical significance of extracolonic findings were analyzed, older age (P <0.001), being female (P = 0.001), presence of symptoms (P < 0.001) and the use of contrast during CT colonography (P = 0.003) were associated with detection of the more significant extracolonic lesions.

Based on these results, it could be concluded that most of the extracolonic lesions detected by CT colonography were lesions of low significance. Careful case selection and use of contrast enhancement would increase the effectiveness of exam. This study is helpful to clinicians to determine the best way to use the CT colonography for detecting highly significant extracolonic lesions.