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Lower GI Series

What is a Lower GI Series?

A lower GI or contrast enema is a test that produces images of a patient’s large intestine, which includes the colon and anus. This test is sometimes called a barium enema. Its full name is lower gastrointestinal tract radiography.

This test uses a form of X-ray called fluoroscopy and a contrast liquid, either a milky white substance called barium or a clear liquid containing iodine. Fluoroscopy makes it possible to see internal organs in motion, kind of like a “live” X-ray. It allows visualization of the colon and rectum and how they function. The contrast liquid helps the bowel to appear more clearly on the viewing screen.

Patients may have this test when they have problems with bowel movements, such as chronic diarrhea, constipation, blood in stools, a change in bowel habits, unexplained weight loss, or abdominal pain.

The test usually takes about 30 minutes.

The lower gastrointestinal tract includes the large intestine, the appendix, and the rectum.

The lower gastrointestinal tract includes the large intestine, the appendix, and the rectum.

Who performs a contrast enema?

A radiologist and radiological technologist perform the test.

Is a contrast enema safe?

A barium enema is a type of X-ray, so it uses a small amount of ionizing radiation to produce images. The amount of radiation is very small. The medical benefits far outweigh the small amount of radiation exposure. Parents should discuss any concerns with the medical team.

Fluoroscopic side view of a lower GI series test in a pediatric cancer patient.

Fluoroscopic side view of a lower GI series test in a pediatric cancer patient.

Small green arrow points to an obstruction in the lower gastrointestinal tract on an image from a lower GI series test

The small green arrow points to a problem area in the large intestine on an image from a lower GI series test.

What must patients do to prepare?

  • Empty the colon: The patient’s colon must be empty for the test. If the colon is not empty before the test, the procedure will be canceled.
  • No food or drink other than clear liquids: The patient must not eat or drink anything but clear liquids for several hours before the test. Instructions depend on the pediatric center, the patient’s age, and reason for the exam. Preparation usually involves taking magnesium citrate and drinking lots of water. The patient’s stools should be watery and clear several hours before the test.

How can parents help the patient prepare?

Parents should make sure the patient:

  • Understands why he or she is having the test and what will happen. Child life specialists can help with explanations.
  • Wears loose, comfortable clothing that is easy to change in and out of.

What details should be taken care of before the test?

  • Parents may need to consult with the insurance company to find out how much it will pay for the procedure.
  • Parents should tell the medical team about:
    • Any medications the patient takes, including over-the-counter ones.
    • Allergies, especially to contrast liquid. (It will likely either contain barium or iodine.)
  • Allow plenty of time to get to the center. It is important to arrive at the appointment on time, even a few minutes early to allow time for check-in.
  • The parent and patient will stay in a waiting area until it is time for the procedure. Bring activities just in case the waiting period is long.

What happens during a contrast enema?

  • A radiology staff member will talk with the family about why the patient needs a barium enema and will explain the procedure.
  • The staff member will help the patient onto the X-ray table. The patient will lie on his stomach or side for this test. Infants and young children may use a special device to help them stay still.
  • The technologist or radiologist will insert a small tube into the patient’s rectum. There are different sizes of tubes according to the patient’s size and age.
  • The technologist will use something to keep the tube in place, perhaps tape or a small inflated balloon. The tube will be connected to a bag containing the contrast liquid.
  • The radiologist will move the X-ray machine, also known as “fluoro tower,” over the patient. The contrast liquid will flow through the tube. While the contrast moves into colon, the technologist will gently roll the patient from side to side to get good images.
  • After the test, the technologist will remove the tube and allow the patient to go to the bathroom or put the patient in a diaper until he has a bowel movement. The team may then take additional images.

What will the patient feel?

The tube in the patient’s rectum will feel uncomfortable. The patient will feel like he has to have a bowel movement. There could be some cramping. These feelings will only last a short time.

What will the patient experience after the test?

  • After the study, patients should drink extra fluids because the contrast could cause constipation.
  • At first, the patient’s bowel movement may appear white or grayish if barium is used as the contrast liquid.

How will families find out the results?

The radiologist will interpret the results and send a report to the doctor who ordered the test. A member of the medical team will share results at the next appointment.


Reviewed: June 2018