Small Bowel Follow-Through

What is a small bowel follow-through?

As far as the patient is concerned, the small bowel follow-through is a very straightforward examination. It essentially consists of the patient ingesting at least two large cupfuls of a dilute liquid barium, a substance that enhances X-ray images. Following ingestion, the radiologist will use an X-ray machine to follow the passage of barium through the stomach and into the small intestine, also referred to as the small bowel.

It is possible to evaluate the small intestine in terms of:

  • diameter
  • peristalsis (which means movement)
  • whether or not there is any abnormal filling defect within the bowel
  • whether there is abnormal holdup to the flow of barium

The duration of the examination is variable and essentially depends on the amount of time it takes for the barium to pass from the stomach to the colon (large intestine). Normally, this is approximately one to two hours, but in some patients it may take up to four hours and still be normal.

What happens during a small bowel follow-through?

Once the barium reaches the colon, the radiologist will spend some time examining the terminal portion of the small intestine (the terminal ileum). This may involve some sort of compression device pressing down on the right-lower portion of the patient's abdomen in order to better distend the bowel. Such compression devices (spoon or gloved hand) may be used at any point during the examination in order to better separate loops of bowel and to confirm whether or not they are indeed normal or abnormal.

In order to produce a good examination it is necessary that the small bowel continue to fill with barium and that the barium moves in a satisfactory manner. This is most likely to happen if the stomach remains full and therefore it is necessary for the patient to keep drinking sufficient quantities in order for the stomach to remain distended with fluid.

The radiologist will intermittently screen the patient's abdomen to assess the passage of barium and to take images to document any abnormal findings. In between X-rays it is usual for the patient to lie on their right side in order to encourage fluid to pass from the stomach into the small bowel.

Once the barium has reached the colon, the patient is usually asked to visit the bathroom followed by a single further X-ray in order to provide an overview of the barium within the small and large intestines.

Why is a small bowel follow-through performed?

Your doctor may have previously performed an endoscopy that yielded no conclusive results, and thus may be trying to rule out the following conditions:

  • small bowel obstruction
  • inflammatory bowel disease
  • Crohn's disease
  • neoplasm (a mass that is inconsistent)
  • cancer of the small bowel
  • blood in the stool
  • fresh blood emitting from the rectum