CT Enterography is a specialized scan that uses X-rays and computer imaging to look at the entire thickness of the small bowel wall, as well as the surrounding abdominal organs.
Doctors request this scan to pinpoint inflammation, find hidden bleeding, and locate bowel blockages.
Unlike a standard abdominal CT, this test uses a relatively large volume of oral contrast to distend the small bowel so its wall can be assessed. It can reveal important abnormalities but does not identify every cause of symptoms.
Common Indications for CT Enterography
Your doctor may request a CT Enterography for:
- Diagnosing or tracking inflammatory bowel diseases, especially Crohn's disease.
- Investigating unexplained internal bleeding.
- Locating a small bowel obstruction (blockage).
- Finding small bowel tumors.
- Locating abscesses (pockets of infection).
What does the CT scanner look like?
It looks like a large, illuminated donut. You will lie on a motorized table that smoothly glides you into the opening of the machine.
What happens during a CT Enterography scan?
- Before scanning, you will drink a prescribed volume of oral contrast over a stated period; the volume and formulation vary by centre and patient.
- Once you finish drinking, you will lie flat on the scanner table.
- An IV will be placed in your arm to inject contrast dye.
- You will hold your breath for up to 15 seconds while the machine slides you through the ring to take the pictures.
Do I need to prepare for a CT Enterography scan?
- Follow the centre's fasting instructions; these vary by protocol.
- Arrive at the time requested so there is enough time to drink the oral contrast.
Can I eat or drink before my CT Enterography scan?
Follow the specific food and clear-liquid instructions issued by the centre rather than assuming a universal four-hour fast.
How long does a CT Enterography scan take?
The time inside the scanner is very short (about 10 minutes), but you should plan to be at the clinic for up to 2 hours because of the time required to drink the oral prep.
Are there different types of CT Enterography scans?
Protocols vary in oral contrast formulation and volume, timing, IV contrast, and whether a medicine is given to reduce bowel movement. Follow the instructions for your exact examination.
Why might contrast be needed?
This test uses two types of contrast:
- Oral Contrast: The large volume of liquid you drink inflates the small bowel so the walls aren't collapsed against each other.
- IV Contrast: The dye injected into your arm highlights the blood supply to the intestine, making inflamed or diseased areas shine brightly on the scan.
Is a CT Enterography safe?
Yes. However, because Crohn's disease often affects young people who may need many scans over their lifetime, doctors try to limit radiation exposure when possible. In some cases, they might suggest an MR Enterography instead.
Pregnancy Precaution
Tell the clinician and CT team if you are pregnant or could be pregnant. Ultrasound or MR enterography may be preferred when they can answer the question in time, but CT should not be withheld when it is the most appropriate test for a serious condition and delay could cause harm.
What are the risks of contrast dye?
IV contrast may cause a brief warm flush or metallic taste. Allergic-like reactions can occur and severe reactions are rare; people with acute kidney injury or severe chronic kidney disease require individual review. Oral contrast formulations vary and may cause fullness, cramps, nausea, or diarrhoea. Report injection-site pain or swelling immediately.
Will the scan hurt?
The scan itself does not usually hurt, but the IV, large volume of oral contrast, fullness, cramps, and lying still can be uncomfortable.
What happens after the scan?
Most people can go home afterward. Depending on the oral contrast used, loose stools may occur, so ask the centre what to expect and follow any aftercare instructions.
Sources and further reading
- RadiologyInfo: CT enterography
- ACR Manual on Contrast Media
- FDA: Computed tomography benefits and risks
Conclusion
CT enterography can provide detailed assessment of the small-bowel wall and surrounding tissues. Its usefulness depends on adequate bowel distension, contrast timing, and the clinical question, and endoscopy, MRI, biopsy, or follow-up may still be needed.