MRI scan factsheet


Magnetic resonance imaging (MRI) is a scan that uses magnets and sound waves to take very detailed pictures of the inside of your body. 

The MRI scan looks at soft tissue in the body like the:

  • brain
  • joints
  • heart
  • blood vessels
  • other internal organs.

They are also used to look at:

  • cancer and tumours
  • disease
  • injuries
  • organ damage.

The scan does not hurt, but it can be very uncomfortable. This is because the MRI machine tunnel can feel small, and your child must stay still for a long time.

 Before the test

You will get instructions from the hospital or your child's doctor before the MRI scan, including:

  • what to bring
  • where to go
  • how to prepare.

Instructions can be different depending on what part of the body is being scanned. Some MRI scans do not need any preparation.

Let your child's treatment team know if they have:

  • any allergies
  • asthma
  • kidney problems
  • had any recent surgery
  • claustrophobia – a strong fear of small spaces
  • any metal implants or devices in their body.

MRI and metals

Let your child's treatment team know if your child has had any recent surgery or if they have any metal implants or devices in their body.

The MRI uses magnets, which attract metals. This can be dangerous and affect the quality of the scan. Your child will change into a hospital gown for the MRI scan to make sure that there are no metals on their body.

Speak to your child's doctor if you are unsure about metal devices or implants and the MRI scan.

Sedation and fasting

The MRI scan can be uncomfortable for many children because the machine feels small, and they must stay still for long periods.

Some children can become anxious or frightened, so they may need help getting through the scan. This can include:

  • having a general anaesthetic – medicine that puts your child to sleep during the scan
  • being sedated – medicines that relax your child but are not as strong as a general anaesthetic.

If your child has a general anaesthetic or some types of sedation, they will need to fast. Fasting means no eating or drinking, usually 2 hours before the scan. 

This is to stop your child from aspirating, which can be life-threatening. Aspirating is when food or water is brought up into the lungs during a procedure.

Children who are having a general anaesthetic or some types of sedation will have a small tube placed in their wrist. This is called an intravenous (IV) cannula. This is so the medicine can go straight into the blood stream.


Some children may need to drink a liquid or inject a dye before their scan. This is called contrast. Contrast is a liquid that helps body parts show up clearly on a scan as it goes through the digestive system or the bloodstream. 

Children who need contrast for their scan will have a small tube placed in their wrist. This is called an IV cannula. The contrast will be pushed through the IV cannula before the scan starts.

Contrast dye can make your child sick, so they must fast beforehand.

Let your child's doctor know if they are allergic to contrast or have ever had a reaction to a scan before.

 During the test

The MRI scan is done inside a big machine with a tunnel connected to a flat bed. 

Outside of the room is the radiographer. The radiographer is the person who runs the scan and makes sure all the images are taken. The radiographer will be able to speak to your child while they are inside the machine using a microphone. 

Your child will enter the scanning room and lie on the flat bed. A frame may be placed over the body part that needs to be scanned to help keep it in a good position. 

If your child is sedated or asleep, medical staff will place them on the bed.

The table will slide inside the tunnel, and the scan will start. 

There will be loud tapping and buzzing sounds while the machine takes the pictures. Your child will be given headphones or earplugs to protect their hearing.

In some scans, the bed will move back and forth slightly at different times. This is so the machine can take different pictures. Your child might also be asked to hold their breath at different times, depending on the body part being scanned.

Each set of scans can take between 30 seconds and 7 minutes. It can take 20 to 120 minutes to take all the scans needed.

Between scans, the radiographer will speak to your child to make sure they are okay and encourage them to stay still. If your child moves during the scan, the images may need to be retaken.


Supporting your child during an MRI scan

MRI scans can be uncomfortable for children or cause anxiety.

Parents and carers can stay with their children during the scan for support if they are not pregnant. 

Another staff member can stay with your child if you cannot, and your child will be able to speak to the radiographer through the microphone.

Your child will be given a buzzer to squeeze if they need the scan to stop at any time.

You can also contact the Child Life Therapy team at your local hospital for information on how to support your child through stressful procedures and scans.

Keeping your child occupied during an MRI scan

Because MRI scans are so long, children can become bored and restless. Some children might fall asleep, but others need something to occupy them.

Your child can listen to their favourite music or watch their favourite movies and TV shows inside the machine. You can bring CDs or DVDs from home to play during the scan.

Last updated Friday 19th January 2024


This factsheet is provided for general information only. It does not constitute health advice and should not be used to diagnose or treat any health condition.

Please consult with your doctor or other health professional to make sure this information is right for you and/or your child.

The Sydney Children’s Hospitals Network does not accept responsibility for inaccuracies or omissions, the interpretation of the information, or for success or appropriateness of any treatment described in the factsheet.

© Sydney Children’s Hospitals Network 2024