Lower gastrointestinal (GI) tract radiography, also called a lower GI or barium enema, is an x-ray examination of the large intestine, also known as the colon. This examination evaluates the right or ascending colon, the transverse colon, the left or descending colon, the sigmoid colon and the rectum. The appendix and a portion of the distal small intestine may also be included.
An x-ray (radiograph) is a noninvasive medical test that helps physicians diagnose and treat medical conditions. Imaging with x-rays involves exposing a part of the body to a small dose of ionizing radiation to produce pictures of the inside of the body. X-rays are the oldest and most frequently used form of medical imaging.
The lower GI uses a special form of x-ray called fluoroscopy and a contrast material called barium or a water soluble iodinated contrast. Fluoroscopy makes it possible to see internal organs in motion. When the lower gastrointestinal tract is filled with barium, the radiologist is able to view and assess the anatomy and function of the rectum, colon and sometimes part of the lower small intestine.
Before the test, you will be given special instructions and a medication called Colyte to clean out your colon. This should make you have several bowel movements the day and night before your exam. You will need to pick up Colyte from a pharmacy or drugstore using your referral from your doctor. Two days prior to exam, you will only be allowed clear liquids after 12 noon (no red jello or liquid with sediment). One day prior to exam, begin drinking the Colyte according to the manufacturer’s directions. The morning of the exam, have nothing to eat or drink. If you have any special dietary restrictions, check with your physician.
A technologist will position you on the fluoroscopy table and a scout image will be taken to determine if the colon is empty. The technologist will insert a small tube into the rectum and a small balloon will be inflated to hold the tube in place. The radiologist will control the flow of barium into your colon and you will be asked to roll on the table to ensure the colon is coated with barium. Sometimes air is added to the barium to help distend the walls of the colon for increased viewing. You will also be asked to move into different positions and hold your breath while the technologist takes several images of the colon.
As the barium begins to fill your colon, you will experience pressure and the urge to have a bowel movement. This feeling will usually subside. You may feel cramping and the sense of urgency during the procedure. Taking slow, deep breaths will help lessen this feeling. Let the technologist know if you are having difficulty.
Once the exam is complete, excess barium will be drained back into the tubing. The patient will then be escorted to the restroom to expel the remaining barium. This exam takes approximately 30-60 minutes to complete.
After the exam, you can return to a normal diet. Your bowel movements may appear white for a few days. It is recommended that you drink additional water to help the barium clear the colon.