Virtual Colonoscopy

What is a CT or “virtual” colonoscopy?

A CT colonoscopy is a CT scan of your abdomen after the colon has been gently filled with air. The scan is then sent to a computer workstation where the data is analyzed.

Will I need to prep for the exam?

You will use a prep called the Lo-So Prep.  This includes a liquid diet, laxatives and a suppository to clean your bowel.  The bowel must be free of fecal residue (stool) which can be confused with growths such as polyps and cancers.  This prep is available at any SJRA location that offers CT scans (not available in Pennsauken or Sicklerville).

Does the test have any risk?

Essentially, no. As opposed to traditional colonoscopies, where there is a 1 in 1000 risk of perforating the colon, CT colonoscopy has no such risk. The only risk to the test is from the small amount of radiation from the scan.  Studies have shown the benefits of a CT colon exam in terms of cancer detection outweigh any theoretical risk from radiation exposure.

Will I need to be sedated?

No. You do not need sedation for this exam. Most traditional colonoscopies take the better part of a day, allowing for recovery from sedation. You can drive yourself to and from a virtual colonoscopy!

Is the test painful?

Most people describe the test as mildly uncomfortable. This is due to the need to insufflate air into the colon. Most studies in which patients have had both traditional and virtual colonoscopies show people rate the virtual exam less uncomfortable than the traditional study.

How long does the test take?

You will be on the CT table for about 15 minutes which will include the set up time, scan time (approximately 5 minutes) and scan processing time.  You will have your bowel filled with air for about 5-7 minutes and then you may use the restroom.

Will I need to take off from work for the exam?

No. You will not be sedated, so you can go to work. You can start your prep at home the night before the exam rather than going on a limited diet the day before the exam. We use the 18 hour prep, which starts at noon the day before your exam to minimize your inconvenience.

Are there any other benefits to this exam compared to standard invasive colonoscopies?

Yes. Because we image not just the colon we can see other abdominal organs. Early kidney cancers, liver cancers, kidney stones, and other diseases can be found. Occasionally, incidental findings that are not clear, such as renal cysts, may require another test to better define them such as an ultrasound or an MRI scan.

How accurate is the test?

This is a very difficult question to answer. CT colonography is an evolving technology. Most recent published studies with modern multislice equipment such as we have at SJRA show detection rates (sensitivity) of 90-95% for polyps greater than 1 cm in size. This is critical, since polyps smaller than this have a much lesser chance of harboring cancer or developing into a cancer; however, no test, including a traditional colonoscopy is 100% accurate, even with the best equipment in the best of hands.

Is the test covered by insurance?

Coverage varies by payor and indication.  You can check with your carrier to see if they will cover your examination.

What happens if the test is positive?

Generally, you will need to consider a traditional colonoscopy or a flexible sigmoidoscopy depending on the location of the abnormality.


Because we have the most advanced and current equipment. Our preferred relationship with Siemens Medical Systems allows us to have the most advanced computers for analyzing your colon.

Which test is right for me?

We have provided the following chart on CT colonography and traditional colonoscopy for your comparison to educate you and help you make an informed decision.  Please feel free to talk to any of our Radiologists at any time if you have any questions.

Which test is right for me?

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