CT Colonography

Computed Tomography (CT) Colonography is a minimally invasive exam to screen for cancer of the large intestine, also known as colon cancer. Colon cancer is common, affecting almost 1 in 20 people.

In most cases, symptoms of colon cancer, such as persistent abdominal pain, rectal bleeding or blood in the stool, don’t appear until the disease is in its advanced stages. CT colonography has a much lower risk of perforating the colon than conventional colonoscopy. Most people who undergo CT colonography do not have polyps and can be spared having to undergo a full colonoscopy which typically requires sedation.

As part of its recommendation, the American Cancer Society suggests CT colonography as an option once every five years. Individuals at increased risk or with a family history of colon cancer may start screening at age 40 or younger and may be screened at shorter intervals (for example, having a colonoscopy every five years). Capitol Imaging Services recommends discussing colon cancer screening options with your doctor or medical provider to determine whether CT colonography is a good option for you.

When would I get a CT Colonography?

Typically, CT colonography may be used to screen for colon cancer in people who are at least 50 years of age and at average risk for the disease. Some people with an increased risk, such as those with a family history of colon cancer, may need to start screening sooner.

Your medical provider may recommend a CT colonography if:

  • you are reluctant to have a traditional optical colonoscopy
  • you are at risk of traditional colonoscopy complications such as excess bleeding if your blood doesn’t clot normally
  • you have a bowel obstruction
  • you do not have a history of colon cancer or abnormal tissue clumps, known as polyps, in your colon
  • you do not have a family history of colon cancer or colon polyps
  • you do not have Crohn’s disease or Ulcerative Colitis
  • you do not have Acute Diverticulitis

What Will I Experience?

Before the exam, patient preparation is required so that the bowel is as empty and clean as possible. It is important to cleanse the bowel so that stool is not mistaken for a polyp. Most bowel preparation is safe and well tolerated. Your doctor will instruct you on which of your medications you should continue to take or discontinue before your exam.

The technologist will explain the procedure. You will be asked to lie in the CT scanner. The technologist will insert a short catheter into the rectum. Air is introduced into your bowel via a specially designed pump.

Once there is sufficient air, the technologist captures images through the entire bowel. You will be asked to lie in different positions to distribute the air before taking the images.

After the exam is completed, most patients feel sufficiently comfortable to return to their normal activities. You will be able to eat and drink normally.

Typically, a CT colonography exam takes approximately 15 to 20 minutes to complete.