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CRMA
CT · Targeted study

CT enterography

A CT scan targeted at the small bowel, performed after drinking an oral contrast that distends the bowel loops. It is often requested in the study of Crohn's disease and other conditions of the small bowel.

Duration≈1h15 total
EquipmentPhilips 128-slice
ContrastOral + IV
Preparation4 h fasting + oral contrast
CRMA's Computed Tomography (CT) scanner, in Faro
In summary

A CT enterography (Entero-CT) is a CT scan (also known as a CAT scan) targeted at the small bowel. Before the exam, you drink an oral contrast prepared at the clinic over 45 minutes, which distends the bowel loops to make them clearly visible. It is often requested in the study of Crohn's disease. At CRMA, in Faro, it is performed on a 128-slice scanner; between preparation and exam, allow about 1h15 at the clinic.

What is assessed in a CT enterography?

A CT enterography allows assessment of the small bowel — a part of the digestive tract that is difficult to study by other methods — including the wall of the bowel loops, their distension and the neighbouring structures (mesentery, lymph nodes, vessels). Distension with oral contrast is what makes the bowel wall clearly assessable; the intravenous contrast complements the study. It is often requested in the study of Crohn's disease — activity, extent and complications.

There is also MR enterography, the equivalent exam by magnetic resonance imaging, without radiation, often preferred in young patients who need repeated exams. The choice rests with the referring doctor. The report is produced by a radiologist; the clinical interpretation rests with your doctor.

CT enterography: axial, coronal and sagittal slices of the abdomen with the small-bowel loops distended by the oral contrast and enhanced by the intravenous iodinated contrast.

When it is requested

  • Crohn's disease — assessment of activity, extent and complications.
  • Suspected inflammatory disease of the small bowel.
  • Abdominal pain or chronic diarrhoea under investigation, according to clinical guidance.
  • Gastrointestinal bleeding of unexplained cause, after endoscopies.
  • Study of small-bowel changes identified on other exams.
  • Assessment after bowel surgery, according to guidance.

What the exam is like

  • 1Before

    Before the day of the exam

    Buy the product indicated when booking from the pharmacy — one 250 mL bottle of a lactulose solution — and bring it with you. Fast for 4 hours. If you have recent blood tests with kidney function (last 3 to 6 months), it's advisable to bring them. Arrive 1 hour before your appointment time.

  • 2

    Preparing the oral contrast

    At CRMA, the bottle you brought is mixed with 1.5 litres of water, forming the solution you will drink.

  • 345 min

    Drinking the solution

    For the first 15 minutes, drink as quickly as you can; for the remaining time, continue at a normal pace, up to at least 1250 mL. The team supports you throughout the whole process.

  • 4

    Start of the exam

    About 45 to 50 minutes after you start drinking, you go through to the CT room. You remove only the metal objects from the abdomen area (belts, fasteners, piercings).

  • 510–20 min

    Medication and intravenous contrast

    A venous line is placed; a medicine that temporarily reduces the movements of the bowel may be given (it improves image quality), along with the intravenous iodinated contrast — it is normal to feel a passing warmth and a metallic taste. You will be asked to hold your breath for a few seconds during each acquisition.

  • 6

    Finishing

    You can resume your normal day and your usual diet; we recommend drinking water throughout the day. The oral contrast may have a mild, passing laxative effect. If you notice passing blurred vision after the medication, wait for it to pass before driving.

Preparation

  • Buy from the pharmacy: the product indicated when booking — one 250 mL bottle of a lactulose solution — and bring it on the day of the exam. The mixture is prepared at CRMA.
  • Fasting: 4 hours.
  • Arrival: 1 hour before your appointment time, for the preparation with the oral contrast. Allow about 1h15 in total at the clinic.
  • Kidney function: if you have recent blood tests (last 3 to 6 months) with creatinine/kidney function, it's advisable to bring them. They are not mandatory.
  • Medication: keep your regular medication — including metformin — unless your doctor advises otherwise.
  • Iodinated contrast allergy: if you have had a reaction to iodinated contrast, let us know when booking. Each case is assessed individually by the radiologist.
  • Metal objects: remove only those from the area being studied — belts, fasteners, piercings.
  • Pregnancy: CT uses X-rays. If you are or think you may be pregnant, always let us know before the exam.
  • Breastfeeding: always let us know. If the exam is with intravenous contrast, breastfeeding may continue as normal after the contrast is given (ACR/ESUR recommendation).
  • After the exam: you can resume your usual diet. The oral contrast may have a mild, passing laxative effect. If you notice passing blurred vision after the medication, wait for it to pass before driving.
  • Documents: referral, insurer/scheme card (if applicable), previous exams (endoscopies/CT/MRI) and recent blood tests, if you have them.

Results

The report is produced by a radiologist from the images. The report is available as a PDF (by email or printed) and the images on CD and on CRMA's imaging platform, to take to your doctor.

Frequently asked questions

About CT enterography.

Does a CT enterography hurt?

No. It is a painless exam. The most demanding part is drinking the oral contrast solution over 45 minutes. You will also feel the pinprick of the venous line and, with the intravenous contrast, a passing warmth and a metallic taste — normal sensations.

Is a CT scan the same as a CAT scan?

Yes. CT (computed tomography) and CAT (computed axial tomography) are names for the same exam — CAT is the older term, while CT is the term used today. You may come across both: the exam is exactly the same.

How long does it take?

You should arrive 1 hour before your appointment time. Allow about 1h15 at the clinic: 45 minutes drinking the oral contrast, followed by the exam, which takes 10 to 20 minutes.

What do I need to bring on the day of the exam?

The 250 mL bottle of the lactulose solution indicated when booking, bought from the pharmacy, your referral and, if you have them, recent blood tests with kidney function. The oral contrast mixture is prepared at CRMA.

Why do I have to drink so much liquid?

The solution distends the loops of the small bowel, making the bowel wall clearly visible — this is what allows the exam to assess this part of the digestive tract. Drinking the indicated volume, at the indicated pace, is essential for the quality of the exam.

Does the oral contrast have side effects?

It may have a mild, passing laxative effect in the following hours — this is expected, given the type of solution used.

What medicines are given during the exam?

A medicine that temporarily reduces the movements of the bowel may be given intravenously, to improve image quality, in addition to the iodinated contrast. If you notice passing blurred vision, wait for it to pass before driving.

What's the difference between CT enterography and MR enterography?

They assess the same thing: the small bowel distended by oral contrast. MR enterography does not use radiation and is often preferred in young patients who need repeated exams; CT enterography is faster in acquisition. The choice rests with the referring doctor.

Is CT radiation dangerous?

CT uses X-rays. At CRMA, protocols are adjusted to use the minimum dose needed for diagnostic quality, on a recent 128-slice scanner (2026). The exam is performed when the clinical benefit of the information it provides justifies the exposure.

Can I have a CT enterography if I'm pregnant?

CT uses X-rays and, in pregnancy, is only performed when the clinical benefit justifies it, by medical decision. Always let us know, before the exam, if you are or think you may be pregnant.

Ready to book?

Book your CT enterography at CRMA.

In Faro, with personal service in PT, EN and FR. We'll confirm your booking with you during working hours.