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Computed Tomography (CT) Scan

Computed Tomography (CT) imaging uses x-rays to produce cross-sectional images of the body such as the brain, spine, and other parts (Figure 1 and 2).

CT scans are used to detect:

Figure 1 CT scan of the brain

Figure 2 CT scan of the spine

Frequently Asked Questions

How should I prepare for the procedure?

  • Wear comfortable and loose-fitting clothes. A gown will be provided if needed.
  • Inform our staff if you are/have:
    • Pregnant
    • On dialysis
    • On medication (especially diabetic)
    • A history of asthma, kidney or renal disease
    • Any allergies, especially to contrast materials. Medication may be prescribed to reduce the risk of an allergy
    • Breastfeeding patients may consider pumping milk ahead of time should a contrast injection be given
    • Remove all metal objects e.g. hearing aids, jewellery, glasses, dentures, hairpins

What to expect during the procedure?

  • You will be asked to lie on the scanner’s couch, which will be moved into the scanner (Figure 3)

Figure 3 Preparation for CT scan

  • When required, a contrast material may be injected. You may feel a hot sensation and a metallic taste in your mouth that lasts a few seconds
  • Patients are usually alone in the CT room during the scan, unless required to be accompanied
  • Staff will observe you through a window and communicate with you through the intercom
  • You will be asked to wait until the images are verified to be of good quality
  • The test may take up to 20 minutes but the actual scan takes less than a minute

What happens after the procedure?

  • You may resume your usual activities

What are the benefits, risks and limitations?


  • No radiation remains in the body after the scan
  • Usually no side effects
  • Non-invasive, painless and fast, making it a vital imaging tool in acute and emergency settings
  • Repeat images can be taken easily and quickly when necessary


  • Injury to skin, blood vessels and nerves if a large amount of contrast material leaks out from the vessel and spreads under the skin
  • Mild reactions to the contrast material like itching, flushing, mild skin rash or hives, nausea and vomiting may happen. Severe allergy to contrast material such as difficulty in breathing and cardiac arrest is extremely rare


  • Weight limit of 300kg
  • Pregnant patients are advised not to have a CT scan unless necessary