A virtual colonoscopy is a CT scan that looks for polyps or cancer in your colon and rectum. This test uses highly detailed, 3D images to see the entire length of your colon, and you don’t need sedation.
A virtual colonoscopy is an X-ray that looks for polyps (growths), ulcers (sores) and cancer in your colon and rectum. Your colon and rectum are tube-like organs that are part of your large intestine, and they help digest food. A virtual colonoscopy is also called a computerized tomography (CT) colonography.
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Health experts recommend everyone get a screening for colorectal cancer starting at age 45. If you have a higher risk for colorectal cancer, you may need screening at a younger age. Risk factors for colorectal cancer include:
A traditional colonoscopy is different from a virtual colonoscopy in a few ways:
A trained X-ray technician performs your virtual colonoscopy and gathers all the images. Then, a radiologist (a medical doctor who specializes in medical imaging) looks at the images and checks for colon polyps, ulcers or spots that could be cancer or precancerous.
Before your virtual colonoscopy, you’ll do a bowel preparation, or “prep.” This process empties your colon of all stool, so your provider can see your colon and rectum clearly. Your prep for a virtual colonoscopy is similar to the prep you’d do for a traditional colonoscopy. You usually do your prep the day before your virtual colonoscopy.
Your provider will give you instructions on how to complete your virtual colonoscopy bowel prep, which may include:
A complete bowel prep is necessary for a successful virtual colonoscopy. It will cause frequent and watery diarrhea, so plan to stay at home and near a bathroom during your prep period.
The day of your appointment, wear comfortable clothing and don’t wear any jewelry. The X-ray technician will take you to a room with the CT scanner, which looks like a large, donut-shaped machine. Your virtual colonoscopy usually involves these steps:
After your virtual colonoscopy, you can go back to normal activities and eat and drink normally. Because it doesn’t require anesthesia, virtual colonoscopy usually has very little or no recovery time.
You may have some excess gas from the air that was pumped into your colon. This is normal, and the gas may cause some cramping or bloating. Usually, this is not severe.
Benefits of a virtual colonoscopy include:
A virtual colonoscopy uses X-rays, which expose you to a small amount of radiation. Large amounts of radiation over time increase the risk of cancer. However, the amount of radiation from a virtual colonoscopy is small. Experts believe the benefits of detecting colon cancer outweigh this risk.
There’s also a small risk of bowel perforation (tear in your bowel) from inflating your bowel with air. However, the risk of bowel perforation is lower in a virtual colonoscopy compared to a traditional colonoscopy.
You shouldn’t have a virtual colonoscopy if you’re pregnant or could be pregnant. In addition, the contrast medium can interact with some medications and may not be safe for people with certain health conditions. Before scheduling your virtual colonoscopy, tell your provider:
If your provider finds an abnormality or a polyp on your virtual colonoscopy, this doesn’t mean you have colorectal cancer. However, you will need a follow-up colonoscopy so your provider can remove the polyp or abnormality.
In some cases, your provider can perform a colonoscopy right after your virtual colonoscopy. This can be helpful if your provider needs to remove something and you’ve already completed your bowel prep. Or, you may need to schedule your colonoscopy for a later date.
If your results are normal, ask your provider when you should have your next colorectal cancer screening. If you have a low risk of colorectal cancer, you may need a repeat virtual colonoscopy every five years.
Seek medical care right away if you notice these symptoms after your virtual colonoscopy:
A note from Cleveland Clinic
Colorectal cancer is the third most common cancer in U.S. adults, excluding skin cancers. Colorectal screening tests can catch this cancer early when it’s easier to treat. Still, many people don’t get the screening they need because they don’t want a colonoscopy.
With a low risk of complications and a faster recovery, a virtual colonoscopy is a good alternative to traditional colonoscopy for many people. Talk to your healthcare provider about your colorectal screening options to find out which test is right for you.
Last reviewed by a Cleveland Clinic medical professional on 04/20/2022.
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