What is an MRI?
Magnetic resonance imaging (MRI) is a way of taking pictures of the inside of the body without X-rays. MRI uses a strong magnet to make the pictures. This is called an MRI scan.
An MRI scan is fairly noisy but does not hurt. A number of short MRI scans make up a complete MRI study. A complete MRI study may take as little as 30 minutes and up to two hours to complete.
What to tell your child about the MRI
Tell your child exactly what will happen during the MRI scan. Explain what they will see, hear and feel. Here is a description of what happens during an MRI scan. Remember, MRI scans do not hurt!
What happens before an MRI
- Before your child goes into the room, the staff will ask some questions. They want to make sure your child will have no problems being near the strong magnet in the MRI scanner. There are some metal devices and implants that make it impossible to have an MRI.
- Your child will have to empty their pockets completely of everything, including coins, keys, pens, cell phones, wallets and bank cards. They will also have to take off their watch. Your child cannot wear any makeup or jewellery.
- Your child will change into a hospital gown.
What happens during an MRI
- The MRI scanner is a large, round machine with a wide tunnel in the centre.
- Your child will lie on the bed. The technologist will place them in the correct position for the MRI scan.
- When everything is ready, the bed will be moved into the tunnel. Most of your child's body will be inside the tunnel.
- Your child must lie completely still for the whole time of each MRI scan.
- The scanner makes a loud knocking or drumming sound during scanning. Everyone staying in the room will wear ear plugs or headphones to protect their hearing.
- The technologist will talk to your child through a speaker. When the MRI scan is complete, the technologist will help your child off the table.
- In some scanners, there is an entertainment system so your child will be able to watch a movie while having the scan.
- If your child does not need to be asleep during the study, you will be able to stay in the room with your child if you wish. If you wish to stay in the room, you will also need to be screened for metal implants.
Getting ready for the MRI
Tell the MRI team about any metal in your child's body
Because MRI involves a strong magnetic field, certain metal implants could injure your child. Tell the MRI team if your child has had any surgeries, procedures or injuries that involved metal, such as metal rods, plates, screws, braces, clips or body piercing. If your child does have any implants, please give the MRI team information about the type of device and the manufacturer. In some cases, your child may need an X-ray to confirm that it is safe for them to have an MRI. If you have any questions, please contact the MRI team.
Your child may need sedation or general anaesthetic
If your child is old enough and able to lie completely still for about an hour (on average), they will not need to do anything special to prepare for the MRI study.
If your child is not able to lie still for the whole study, they may need a special sleep medicine. If your child is an outpatient and needs to be asleep for the procedure, the MRI unit will give you information about when to stop feeding your child before the appointment.
If your child needs to be asleep for the procedure, the nurse or anaesthesiologist will perform a full medical assessment to make sure it is safe for your child to have the sleep medicine. If it is not safe, your child's appointment will be delayed or cancelled.
Write the date and time of your child's study here:
What to do if you need to cancel your child's appointment
If you have to cancel your child's MRI appointment, please call the department as soon as possible.
If your child has a bad cold and a cough, you should change the time of your child's appointment. Your child will likely be unable to lie still for the whole MRI study. Another patient will take your original appointment time. The need for MRI studies is very high.
If you are late for your child's appointment, we may have to delay or cancel your appointment.
Your child may need a needle for the MRI study
Some MRI scans give the doctor more information when they are done with a special liquid called a contrast medium. This liquid is put into the vein in the hand or arm using an intravenous line (IV). The IV is put in with a small needle. If needed, the IV will be inserted before the MRI scan.
Contrast medium is normally very safe, but it may produce a reaction in rare cases. The team will watch your child very closely during and after the MRI to see if your child has a reaction. The team is trained to deal with these problems if they happen. A member of the team will discuss the risks with you before the MRI.
Members of the MRI team
A team of three or four people will be involved in the MRI study:
- A medical radiation technologist will do the MRI scans.
- A nurse will prepare your child for the scans. If your child is having sedation, the nurse will give the sedation. If your child is having a general anaesthetic, the nurse will assist the anaesthesiologist.
- The anaestheologist is the doctor who gives the general anaesthetic.
- A doctor will check each MRI scan to make sure that the study is complete. Most of the time, this will be a radiologist. This is a doctor who specializes in diagnostic images like MRI scans.
What happens after the MRI study
After the MRI study, outpatients may go home unless they have other appointments at the hospital. If your child has had sedation or a general anaesthetic, you must stay until they are awake. This means your whole visit will usually take three to four hours.
Your doctor will receive a report of the MRI scan. Your doctor will talk to you about the results of the MRI study.
Who to call if you have any questions
If you have any questions, call the MRI centre.
At SickKids
The Hospital for Sick Children (SickKids) patients usually have their MRI study in the MRI Centre at SickKids.
To get to the MRI Centre, take the Atrium elevators to the 4th floor. Follow the hallway between 4A and 4D. This will link to CDIU. At the end of the hallway, turn left.
For the MRI scans, we ask that you arrive 30 minutes before your appointment time. If your child is receiving a general anaesthetic, we ask that you arrive one hour before your appointment time.
If your child's study is at Toronto General Hospital (TGH), the TGH staff will call you to tell you how to get there.
MRI without sedation or general anaesthesia
The WAGS program (Wonderful Alternatives to General Anesthesia & Sedation) provides techniques for alleviating anxiety and reducing the need for general anaesthesia in paediatric diagnostic imaging, particularly in MRI. To learn more about the WAGS program at SickKids, please visit https://www.sickkids.ca/en/care-services/clinical-departments/diagnostic-interventional-radiology/wags/.
