Radiological examinations (CT, MRI, enterography, CEUS)

a) CT scan of the abdomen and pelvis

What is it?

Computed tomography (CT) is an X-ray-based examination that provides a rapid and accurate assessment of the abdominal organs, blood vessels and other tissues. An iodine-based contrast medium is often injected into a vein during the examination to make the organs and blood vessels more visible.

How should I prepare?

• If the examination requires contrast medium, do not eat for 3–4 hours beforehand. You can usually drink water.
• You are advised to drink plenty of fluids before and after the examination, unless your doctor tells you otherwise.
• Tell your doctor in advance if:
  • you have previously had an allergic reaction to contrast medium;
  • you have kidney disease;
  • you have a thyroid condition, particularly hyperthyroidism;
  • you are pregnant or may be pregnant.
• If contrast medium is required, you will usually be asked to provide the results of a recent creatinine test to assess your kidney function.
• If you take metformin, follow the instructions provided by your doctor or radiology department regarding its use before and after the examination.
• For some examinations, you may need to drink an oral contrast medium before the procedure.

After the examination

• If contrast medium was injected, you are advised to drink more fluids that day, unless your doctor tells you otherwise.

b) MRI scan of the abdomen and pelvis

What is it?

Magnetic resonance imaging (MRI) uses a strong magnetic field and radio waves. Unlike CT, MRI does not use ionising radiation. If necessary, a gadolinium-based contrast medium may be injected into a vein.

How should I prepare?

• If the examination requires contrast medium, you may need to provide the results of a recent creatinine test.
• Make sure you tell your doctor if you have:
  • a pacemaker or another implanted electronic device;
  • metal implants, vascular stents or other metallic foreign bodies;
  • claustrophobia;
  • kidney disease;
  • or if you are pregnant.
• If you have an implant card or other documents containing information about your implant, bring them with you to the examination.
• For an abdominal MRI or magnetic resonance cholangiopancreatography (MRCP), you will usually be advised not to eat for 4–6 hours beforehand.
• You will need to remove all metal items, including jewellery, watches and hearing aids, before the examination.

During the examination

• The examination usually takes 30–60 minutes.
• It is very important to remain still.
• You will be given headphones or earplugs because of the noise made by the scanner.

c) CT or MR enterography of the small bowel

What is it?

CT and MR enterography are specialised examinations used to assess the small bowel in detail. They are particularly important for diagnosing and monitoring Crohn’s disease and detecting inflammation, narrowing of the bowel (strictures), fistulas or abscesses. MR enterography is more commonly selected for younger patients and long-term monitoring because it does not use ionising radiation.

How should I prepare?

• Do not eat for 4–6 hours before the examination.
• You may drink water unless your doctor tells you otherwise.
• After arriving at the healthcare facility, you will usually need to drink approximately 1–1.5 litres of a special oral contrast medium gradually over 45–60 minutes. This helps to expand the small bowel and makes it more visible.
• Contrast medium is usually also injected into a vein during the examination.
• In some cases, you may be given medicine that temporarily reduces bowel movement. This can cause temporary blurred vision, so you are advised not to drive that day until your vision has completely returned to normal.
• Some healthcare facilities may require additional preparation, such as a low-fibre diet or bowel cleansing. Always follow the instructions provided by the facility performing your examination.

After the examination

• The oral contrast solution may cause looser stools or abdominal bloating for several hours. This is common and usually passes quickly.
• If contrast medium was injected, you are advised to drink more fluids, unless your doctor tells you otherwise.

d) Contrast-enhanced ultrasound of the abdominal organs (CEUS)

What is it?

Contrast-enhanced ultrasound (CEUS) is a modern ultrasound examination in which a special ultrasound contrast agent made up of microbubbles is injected into a vein. It provides a highly detailed real-time assessment of blood flow within organs and different lesions.

CEUS is most commonly used to assess liver lesions, but it may also be used to examine the pancreas, kidneys, spleen and other organs. The examination can help distinguish benign lesions from malignant ones, assess blood flow within lesions, monitor treatment outcomes following interventional procedures or tumour treatment and, in some cases, avoid the need for additional CT or MRI examinations.

How should I prepare?

• You are usually advised not to eat for 3–4 hours before the examination.
• You may drink water.
• Take any essential medicines as usual with a small amount of water.
• Before the examination, tell your doctor if you are pregnant, have a serious heart or lung condition or have previously had an allergic reaction to a contrast agent.

How is the examination performed?

• The examination begins with a standard abdominal ultrasound.
• An intravenous cannula is inserted into a vein in your arm and used to inject the contrast agent.
• The doctor observes for several minutes as the contrast agent passes through the organ or lesion being examined.
• The entire examination usually takes 20–30 minutes.

Is the examination safe?

The contrast agent used for CEUS is neither an iodine-based contrast medium used for CT scans nor a gadolinium-based contrast medium used for MRI scans. It is not toxic to the kidneys, so many patients do not need a creatinine test before the procedure. Adverse reactions are rare.

After the examination

• You can return to your usual activities and eat and drink immediately after the examination.
• If an intravenous cannula was inserted, it will be removed immediately after the examination.
• Your doctor will discuss the results with you immediately or in accordance with the healthcare facility’s usual procedure.