Virtual colonoscopy (CT colonography)

During a virtual colonoscopy, a CT scan produces cross-sectional images of the abdominal organs, allowing the doctor to detect changes or abnormalities in the colon and rectum. To help create clear images, a small tube (catheter) is placed inside your rectum to fill your colon with air or carbon dioxide.

Virtual colonoscopy takes about 10 minutes and is generally repeated every five years.

The pros:

• Unlike traditional colonoscopy, virtual colonoscopy doesn't require sedation or the insertion of a scope into the colon.

The cons:

• Like standard colonoscopy, a thorough cleansing of the bowel is required beforehand.
• The exam might not detect all small polyps and cancers.
• Diet changes are needed before the test, and medications may need to be adjusted.
• Radiation exposure may be a concern. However, the level of radiation used during a screening CT scan is lower than the amount used in a diagnostic CT scan.
• Since tissue samples can't be taken during the exam, a follow-up colonoscopy might be needed if an abnormality is detected.
• Cramping or bloating might occur afterward.
• The test may detect abnormalities in other abdominal organs and additional tests may be needed to determine the cause.