Colon cancer is formed in the tissues of the colon (large intestine) and affects the digestive system. Virtual CT Colonoscopy, also known as CT Colonography, is used to detect cancer or polyps in the large intestine. Doctors insert a small tube a short distance into the rectum and use gas or air to inflate it and capture images.
Why is it done?
CT Colonoscopy is done in the following cases when a person–
- Is at risk of having colon cancer.
- Needs to drive back home after the procedure.
- Does not want to have sedation.
- Does not want to have a colonoscopy.
- Has a bowel obstruction.
- Is at risk of having complications during the colonoscopy.
What are the Signs/ Symptoms?
- Some signs and symptoms of colon cancer in a patient include:
- Pain or discomfort in the abdomen
- Unusual weight loss
- Continuous change in bowel habits
How to prepare for the test?
- Eat a special diet (only liquids) the day before the exam.
- Take laxatives at night before the exam.
- Take additional agents the day before the exam to differentiate between poops and polyps.
- Inform your doctor if you have any disease related to the kidney, liver, etc.
- Inform the doctor if you are pregnant.
- You may need to stop taking your regular medicines for a day or so.
What are the advantages and disadvantages?
- Less time consuming and non-invasive.
- It provides a more detailed and clear image.
- Can detect any abnormalities that are present outside of the colon.
- It does not require sedation and pain relievers.
- Radiation is not left in the body of the patient.
- X-Rays used in the process should not have immediate side effects.
- It is not recommended for people having active Crohn’s disease.
- Fecal material remains can lead to wrong interpretation.
- During the procedure, the specimen for the biopsy cannot be taken.
- It is completely a diagnostic procedure.
What are the risks involved?
Though it is a safe process but some risks could be –
- Pain in the abdomen
- Blurry vision
- Tear in the colon or rectum
- Exposure to radiation
- Chances of cancer due to excessive exposure to radiation
Doctors would interpret the test and deliver the result:
If the doctor finds everything to be normal, the result would be negative. This means you are not having colon cancer and are at the average risk of cancer. The only risk factor could be age and your doctor may ask you to take this test again in the next 5 years.
If the images show any abnormal tissue in the colon or any polyps, then the result is positive. The doctor might ask you to undergo a traditional colonoscopy to get the polyps removed and the samples of the abnormal tissue. It can be performed on the same day as a CT colonoscopy.
If the images show any other problem outside the colon such as in the kidney or the pancreas, then the doctor might recommend an additional test to detect their causes.