Magnetic Resonance Imaging (MRI)

Magnetic Resonance Imaging (MRI) is a non-invasive medical imaging test that uses magnetic fields and radiofrequency waves to see the inside of our body.

MRI is used to detect:

• Brain tumours
• Traumatic head injury
• Developmental anomalies
• Multiple sclerosis
• Stroke
• Dementia
• Infection
• Brain aneurysms
• Arteriovenous malformations (AVM)
• Spine and spinal diseases

Frequently Asked Questions

How should I prepare for the procedure?

• Complete an MRI safety questionnaire
• Continue with your regular diet and medications, except those for sedation
• Do not use make-up, perfumes, hair products and medicinal patches on the day of your test
• Remove all metal objects e.g. hearing aids, jewellery, glasses, dentures, hairpins
• Inform our staff if you are/have:
• Pregnant
• Metallic clips/implants in your body
• Unable to keep still during the scan or fear enclosed spaces. Our clinicians may prescribe mild sedatives before the test
• Breastfeeding patients may consider pumping milk ahead of time

What to expect during the procedure?

• You will be asked to lie on the MRI couch
• The MRI coil may be placed over the area being studied
  After the initial positioning, the couch is moved into the center of the tunnel. The staff will leave the room just before the MRI is carried out (Figure 1)

Figure 1 Preparation for MRI scan

• Staff will observe you through a window and closed-circuit TV, and communicate with you through the intercom
• Patients are usually alone in the MRI room during the scan, unless required to be accompanied. If so, the accompanier must undergo a safety screening
• During the scan, a faint knocking or thumping sound may be produced by the machine. Earplugs/earphones with piped-in music will be provided
• For emergencies, press the buzzer given
• The scan takes between 20 minutes to more than an hour, depending on the area to be scanned. Remain still throughout

What happens after the procedure?

• You may resume your usual activities, unless sedated
• Sedation will usually last for the duration of the scan. After resting, you should be able to go home preferably accompanied

What are the benefits, risks and limitations?

Benefits

• Non-invasive, painless and does not involve exposureto radiation
• No known side or after-effects
• Abnormalities blocked by overlying bones may be seen more clearly
  

Risks

• Generally safe when safety guidelines are followed
• Undetected implants containing metal may affect the scan
• In very rare instances, patients with very poor kidney function may suffer from Nephrogenic Systemic Fibrosis, a rare disease that leads to thickening/hardening of the skin and deposits around the body if high doses of contrast material are injected
  

Limitations

• Weight limit of 200kg
• Patient movement and metallic clips/implants will affect quality of scan produced
• Pregnant patients are advised not to have a MRI scan unless necessary
• Takes longer compared to a Computed Tomography (CT) scan