Computerised Tomography (CT)

About the examination

A Computerised Tomography (CT) scan uses X-rays and computer systems to create three-dimensional images of different areas of the body. During a CT scan, the patient lies on the CT table which moves in and out of a large, donut shaped scanner, taking multiple images of the area being scanned.

What parts of the body is examined by CT?

A CT scan can be used to examine most parts of the body including:

  • Internal organs
  • Blood vessels
  • Bones and joints

Why is a CT required?

CT’s can be used to diagnose and monitor a variety of conditions and disorders. It can also be used to guide procedures such as biopsies or therapeutic injections.

What are the possible risks and complications of a CT?

A CT is a relatively low risk procedure as it is non-invasive.

CT uses radiation technology and it has not been demonstrated that there is any risk from the doses of radiation used in medical imaging. Your referring Doctor has deemed that there is clinical benefit from performing the CT scan.

If deemed clinically necessary, an injection of contrast media may be required. Some people can be allergic to the contrast media, and this is more likely if you have other multiple severe allergies. Allergic reactions to the X-ray dye are usually mild such as nausea, vomiting and hives.

There is a very minor risk that patients may suffer from a severe reaction to the contrast medium and experience:

  • Breathlessness
  • Low blood pressure
  • Anaphylactic shock
  • Cardiac arrest

Are there alternatives to CT?

Depending on the area being examined and clinical history, doctors may consider an Ultrasound or MRI instead of a CT.

Preparation for a CT

What should you tell us when making a booking for a CT?

  • If you are pregnant
  • If you are diabetic
  • If you have kidney problems
  • If you have multiple severe allergies, or a previous allergy to contrast media

You may be asked to have a blood test to check your kidney function before the test, and definitely if you are diabetic.

What special diet is required before a CT?

You may be instructed to fast for 4 hours prior and/or come well hydrated. For some examinations of the abdomen, you may be asked to come in prior to your appointed scan time to drink an oral contrast. Please follow all instructions given at the time of your booking.

What to bring for a CT?

Your doctor may ask you to bring any previous scans or X-rays to the procedure, along with any medications you’re currently taking.

What to wear for a CT?

You will be asked to remove any metallic items, such as jewellery, watches, eyewear and belts, as these items can show up on the CT images.

You may be asked to remove any clothing obstructing the area to be scanned and given a medical gown to wear instead, so you should try and wear something that is comfortable and easy to remove.

How long will a CT take?

Depending on the area being imaged, the duration usually takes between 10 and 30 minutes.

CT Procedure description

What does a CT involve?

After arrival at the Radiology Department, the radiographer may ask you to change into a gown if necessary. You will be taken to the CT Scan Room, and asked to lay on the CT bed. If the procedure requires an injection of contrast media, the radiographer or radiology nurse will insert a cannula usually on the inside of your elbow. You may be asked to hold your breath during the scan, this is very important.

If an injection of contrast media is required, this will happen following some planning scans being done. You may experience the following sensations as the contrast agent moves through the body:

  • Warmth or heat
  • Mild burning
  • A metallic taste or smell
  • A feeling as though you have passed urine

Post CT instructions

What are the recovery details?

You may be asked to stay on-site for up to an hour after the CT, to ensure that there are no side effects or reactions to the contrast medium.

After the procedure, you will be able to return to normal activity the next day. The results of the scan will be sent to your doctor, who will discuss them with you during your next appointment.

Can I drive home?

Most patients are able to drive home after the procedure. If you have had a therapeutic spinal injection, you may be required to have someone drive you home.