X-Ray Exams of the Digestive Tract
Lower GI Tests continued...
This lower GI testing is used to detect:
- Colon polyps
- Diverticular disease
- Strictures or sites of narrowing and obstruction
- Ulcerative colitis or Crohn's disease
- Other causes of abdominal pain or blood, mucus, or pus in the stool
There are several types of tests used to view the lower GI, including:
- Air contrast barium enema (double contrast barium enema). This is an X-ray examination of the large intestine (colon). Barium and air are introduced gradually into the colon by a rectal tube. Approximate time: 1 hour.
- Barium enema. This is an X-ray examination of the large intestine (colon). Barium is introduced gradually into the colon by a rectal tube. Approximate time: 1 hour.
With the barium or contrast enema, the colon is filled with a contrast material containing barium or iodine-containing contrast (a liquid that lights up on X-ray) by running it through a tube inserted into the rectum. The barium blocks X-rays; therefore the colon, when filled with the agent, shows up clearly on the X-ray picture.
The air contrast study is slightly different. The colon is first filled with some barium, and then the colon is filled with air. This technique provides a more detailed picture of the lining of the colon, improving the procedure's ability to detect small polyps or inflammation.
What Should I Do Before the Upper or Lower GI Studies?
Preparation for upper GI or lower GI testing usually includes making dietary changes (such as following a low-fiber diet for two to three days before the test), not smoking for 12 to 24 hours before the test, not taking any medications for up to 24 hours before the test and not eating anything for 12 hours before the test. Your doctor will give you specific instructions. Never stop taking any medications without first discussing it with your doctor.
Additional preparation for the lower GI test usually includes taking oral laxatives and an enema the night before the test. Please follow the pretest directions given to you by your doctor carefully and ask questions if you do not understand them.
What Happens During the GI Tests
During GI testing:
- You will be positioned on a tilting X-ray table by the technologist. For an upper GI test, the table usually starts in a vertical position, with the person standing. For a lower GI test, the table usually starts in a horizontal position, with the person lying on his or her back or stomach. The table will be tilted at various angles during the test to help spread the barium solution throughout the body so that different views can be seen on the fluoroscope. During the test, the radiologist may put pressure on your abdomen to get a clearer image on the fluoroscope.
- Although the barium solution given in an upper GI test is unpleasant tasting, there is no pain and little discomfort during the procedure. The lower GI test may cause some discomfort, including cramps and a strong urge to have a bowel movement.
- After the barium enema is administered in a lower GI test and a few X-rays are taken, you will be helped to the bathroom (or given a bedpan) and asked to move your bowels to expel as much of the barium as possible. Then you will go back to the X-ray examination room where more X-rays will be taken of the barium solution that remains on the lining of the intestine. In some cases, air will be injected slowly into the colon (air contrast barium enema) to provide further contrast on the X-rays to detect abnormalities.