Computed tomography colography

Computed tomography colonography (CTC), also known as virtual colonoscopy, is a medical imaging procedure that uses computed tomography (CT) scanning to produce two- and three-dimensional images of the colon (large intestine) and the distal part of the small intestine. It has been developed as a minimally invasive method to examine the colon and rectum, and is a potential alternative to traditional colonoscopy.

Procedure

CTC begins with the preparation of the colon, which involves a clear liquid diet and consumption of oral contrast agents to tag residual fluid and stool. The patient is then positioned on the CT scanner table, and a small, flexible tube is inserted into the rectum to inflate the colon with air or carbon dioxide. The CT scanner then takes a series of images of the colon, which are processed and interpreted by a radiologist.

Applications

CTC is primarily used for colorectal cancer screening, especially in patients who are unable or unwilling to undergo traditional colonoscopy. It can also be used to investigate unexplained changes in bowel habits, abdominal pain, and rectal bleeding, and to follow up on findings from other imaging tests.

Advantages and Disadvantages

The main advantages of CTC over traditional colonoscopy include its non-invasiveness, the absence of sedation, a lower risk of complications, and the ability to visualize other abdominal and pelvic structures. However, it also has some disadvantages, such as the inability to remove polyps or take tissue samples during the procedure, the exposure to ionizing radiation, and the potential for false-positive or false-negative results.

See Also

• Computed tomography
• Colonoscopy
• Colorectal cancer

References

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