Lower GI exam also called a barium enema is a test to evaluate the colon using barium. This test is less commonly performed now because of colonoscopy. It is occasionally ordered when a colonoscopy is incomplete or when a patient can’t tolerate the colonoscopy. The goal is to primarily detect polyps and masses. There are also more specific reasons a lower GI is ordered, like after surgery to check for leaks.
The lower GI exam is done in the radiology department. A radiology doctor will supervise the exam and a technologist will assist him. An X-ray is done to make sure there is no retained stool in the colon. You will be provided instructions on how to prepare for the exam, as far as diet, laxatives and any enemas you may take.
You will be placed on a flat fluoroscopy table which is a continuous form of X-ray. A tube will be placed into your rectum so that the barium contrast can be placed. Once this is done, the radiologist will start placing the barium contrast and monitoring with X-ray. He will also place air into the colon so that it can be distended and better evaluated.
The radiologist will monitor the exam using the X-ray or fluoroscopy. After the barium is placed, you may feel pressure and cramps. This will go away once the test is done and you let some of the gas out. Once the entire colon is filled with barium and nicely distended by air, the radiologist will take focused X-rays followed by more general overhead X-rays taken by the technologist. These will include different projections. The technologist will ask you to go to the bathroom and have you try to expel the barium. He will then take an X-ray after that.
After all the X-rays are taken, the exam is sent to the radiology doctor for interpretation. There are lots of pictures to scrutinize. The radiologist will look for polyps, masses, narrowed areas and other abnormalities. The radiologist will issue a report to your doctor with the findings and any limitations.