Colonoscopy is usually the preferred test used to examine the digestive tract. However, there are several commonly performed X-ray tests that allow your doctor to examine your digestive tract from the esophagus to the rectum.
These tests utilize barium or an iodine-containing agent that allows visualization of the digestive tract and a form of X-ray machine called fluoroscopy. Fluoroscopy allows part of the body to be studied in motion and recorded on a video monitor.
Although there are many theories about what causes Crohn's disease, none of them have been proven. So exactly what causes it is unknown. There is a benefit, though, in understanding the possible causes of Crohn's disease and how they interact with one another. Doing so can help one better understand the symptoms, diagnosis, and treatment of Crohn's disease.
Scientists believe that Crohn's disease is caused by a combination of these factors:
Immune system problems
Fluoroscopic examinations of your GI tract may be performed in a doctor's office, a commercial X-ray facility, or a hospital. These tests are usually called either an "upper GI" or a barium or contrast enema or a "lower GI", depending on the organs to be studied.
Upper GI Tests
Upper GI tests use X-rays to examine the esophagus, stomach, and first part of the small intestine (the duodenum). See the article The Digestive System to learn more about these organs.
For these tests, you need to drink barium. As the barium passes through the digestive tract, it fills and coats the esophagus, stomach, and first part of the small intestine making them more visible with X-ray. Then a fluroscope machine is held over the part of the body being examined and transmits continuous images to a video monitor.
This upper GI test is used to diagnose:
Obstruction or narrowing of the upper GI tract
It may also be used to determine the cause of:
Reflux symptoms (dyspepsia or heartburn)
Unexplained vomiting, weight loss, or bleeding
There are several types of tests used to view the upper GI tract, including:
Barium swallow. This is an X-ray test that examines how food moves down the esophagus to the stomach. Approximate time: 30 minutes.
Modified barium swallow. This test looks at the beginning of swallowing from the mouth to the pharynx and down to the esophagus. Approximate time: 30 minutes to 1 hour.
Upper GI series. This is an X-ray examination of the esophagus, stomach, and upper part of the small intestine. Approximate time: 30-45 minutes.
Small bowel series. This is an X-ray examination of the small intestine (small bowel). Approximate time: 2 to 4 hours, depending upon how long it takes for the barium to reach the colon.
Lower GI Tests
Lower GI tests or barium enemas are used to examine the large intestine and the rectum. For this test, barium or an iodine-containing liquid is introduced gradually into the colon through a tube inserted into the rectum. As the barium passes through the lower intestines, it fills the colon, allowing the radiologist to see growths or polyps and areas that are narrowed. The fluoroscope is held over the part of the body being examined and transmits continuous images to the video monitor.