Computed Tomographic Colonography (CTC)

Computed Tomographic Colonography, also known as Virtual Colonoscopy, is a medical imaging procedure used to visualize the colon and rectum. It uses computed tomography (CT) scans to produce high-resolution images of the colon and rectum, allowing for the detection of polyps, tumors, and other abnormalities.

Procedure

The CTC procedure typically involves the following steps:

• The patient is instructed to prepare for the exam by following a special diet and bowel preparation regimen, which may include laxatives or enemas to cleanse the colon.
• The patient lies on a table that slides into the CT scanner, a large, doughnut-shaped machine.
• A small tube is inserted into the rectum to inflate the colon with air or carbon dioxide, which helps to distend the colon and provide clearer images.
• The CT scanner takes a series of X-ray images of the abdomen and pelvis, which are then reconstructed into detailed cross-sectional images of the colon and rectum.
• The procedure typically takes about 10-15 minutes to complete.

Indications

CTC is commonly used for:

• Screening for colorectal cancer in average-risk individuals
• Detecting polyps and tumors in the colon and rectum
• Evaluating symptoms such as abdominal pain, changes in bowel habits, or bleeding
• Monitoring patients with a history of colorectal cancer or polyps

Advantages

The advantages of CTC include:

• Less invasive than traditional colonoscopy
• No sedation required
• Faster procedure time
• Lower risk of complications, such as bleeding or perforation
• Able to visualize the entire colon and rectum, including areas that may be difficult to reach with traditional colonoscopy

Limitations

The limitations of CTC include:

• May not detect small polyps or flat lesions
• Requires bowel preparation and air insufflation, which may cause discomfort
• Exposes patients to radiation, although the dose is typically low
• May require additional testing, such as colonoscopy, if abnormalities are detected

Interpretation

The images obtained from CTC are interpreted by a radiologist, who looks for signs of polyps, tumors, or other abnormalities. The results are typically reported as:

• Normal: No abnormalities detected
• Polyp(s) detected: One or more polyps are present, which may require removal and further evaluation
• Tumor detected: A tumor is present, which may require biopsy and treatment
• Inconclusive: Additional testing, such as colonoscopy, may be required to confirm the diagnosis

Frequently Asked Questions (FAQs)

What is Computed Tomographic Colonography?
A medical imaging procedure used to visualize the colon and rectum.

How does it work?
Uses X-rays and computer technology to produce detailed images of the colon.

Is it invasive?
Minimally invasive, requiring insertion of air or carbon dioxide into the colon.

What is the purpose of Computed Tomographic Colonography?
To detect polyps, cancer, and other abnormalities in the colon.

Is preparation required?
Yes, typically including bowel cleansing and dietary restrictions.

Are there risks associated with the procedure?
Generally considered safe, but may include radiation exposure and discomfort.

Can it replace traditional colonoscopy?
May be used as an alternative for some patients, but not for all.

How long does the procedure take?
Typically around 10-30 minutes.

Are the results immediately available?
Usually, but may require additional time for interpretation by a radiologist.

Is Computed Tomographic Colonography covered by insurance?
Coverage varies depending on the insurance provider and individual policy.