What Happens During a Double-Contrast Barium Enema (DCBE)?

A DCBE is also called a lower gastrointestinal series. It is a way to use X-rays to locate polyps and colon cancer. It is a very effective tool for finding large colon polyps and cancer. But it only finds polyps smaller than 1 cm about half the time. So it is a better exam for diagnosing colorectal cancer than for catching it early. Consequently, it is used mainly when you can’t have a colonoscopy, but it is not considered standard of care at this time.

During a DCBE, the doctor takes X-rays of your colon and rectum. Because the walls of the colon are very thin, they don’t absorb X-rays well and can’t create a good picture. So contrast material is used to coat your bowel wall and highlight abnormalities. Two materials are commonly used. The most effective one for coating the bowel wall is barium. Barium is a thick, chalky, white material. Gastrografin is a liquid used occasionally instead of barium. However, it is not as effective. You get the barium as an enema so that it fills your entire colon. You will be asked to change your position to help the barium move around throughout your large intestine. This can be uncomfortable. With barium alone, large polyps or cancers can be seen on the X-ray. To get a better picture, though, so that smaller polyps and abnormalities can be seen, air is blown into your colon after the barium to create a “double contrast” image.

A DCBE can be an uncomfortable examination. There are, though, few risks associated with it, and it does not require any kind of sedation. It does require a complete bowel-cleansing preparation the day before to empty your bowel. It is also necessary to hold the barium inside your colon for the whole exam, which can last 1 to 2 hours.