The radiologist or technologist will then make the contrast injection by inserting a small tube into the rectum. A mixture of barium and water is passed into the patient s colon through the tube. To help the barium thoroughly coat the lining of the colon, air may also be injected through the tube. Then a series of images is captured. The patient may be repositioned frequently, to enable the technologist to capture views from several angles.
Some newer equipment allows patients to remain in the same position throughout the exam.
During the study, the radiologist will view the films and request special views or close-ups. Once the x-ray images are completed, most of the barium is drawn back into a bag, and the patient is directed to the washroom to expel the remaining barium and air. In some cases, the technologist may then take additional images to help the doctor see how well the colon has cleared. The patient is then released. A lower GI study typically takes between 30 and 60 minutes.