The page explains about having a cardiac MRI scan without general anaesthetic and what to expect when your child comes to Great Ormond Street Hospital (GOSH) to have this procedure.
Magnetic resonance imaging (MRI) is a way to take pictures of the body using a large magnet, radio waves and a computer. The machine takes pictures without touching the body. It does not hurt and does not use X-rays or any radioactive radiation.
The MRI machine is shaped like a short, open-ended tunnel and sits in a large room. The patient lies down on a flat scanning bed that slides into the tunnel.
For more information, watch our video podcast about having an MRI.
Is cardiac MRI safe for everyone?
If your child has a cardiac pacemaker or other metal devices in their chest or aneurysm clips in their head, then the magnetic field of the MRI scanner may not be safe for them. If your daughter is 12 years old or older, we will ask her about her periods and any possibility she could be pregnant. Please contact our booking office on the numbers below if you have any questions about safety.
Where is the Cardiac MRI Unit at GOSH?
When you arrive at the hospital, please come first to the main reception desk just inside the front doors. From there, you will be directed towards the lift or stairs to Level 1 and follow the signs to the Cardiac MRI Unit reception desk. The Cardiac MRI Unit is in the basement (Level 1) of the Variety Club Building at GOSH.
What happens if my child is unwell before or at the time of the appointment?
If your child is unwell or there is another reason that you cannot keep the appointment, please inform the booking office as soon as possible. Sometimes, we can offer the appointment to another child on the waiting list and it will enable us to book you another appointment.
What time should I arrive?
Please arrive at least 15 minutes before the scheduled start time of the scan, so we can register your child, answer any questions and check that they are fit and well for the scan. We also need to check that they are safe to go into the magnetic environment of the MRI scanner. If you arrive late, we may have to cancel the investigation.
What should I wear?
Your child should wear comfortable clothing without metal zips or fasteners, such as a tracksuit and t-shirt. He or she can wear these clothes for the scan if they do not have any metal zips or fasteners. We also have a changing room and gowns your child can wear if preferable.
If you are accompanying your child into the scanning room, you will need to remove all metal objects such as watches and glasses, but metal in your clothing, such as zips or fasteners, is safe to wear.
May I eat and drink before the scan?
As long as your child is not having a general anaesthetic, he or she can eat and drink before the scan.
Please note: if your child is booked to have the scan under general anaesthetic, they cannot eat and drink beforehand. Please read our information about having a cardiac MRI scan under general anaesthetic.
What will happen first?
We will greet you at our reception desk, check our metal object safety sheet with you and your child before guiding you both to change into a gown if necessary. We have changing rooms and lockers in which you can leave your clothing (if necessary), keys, coins, watches, rail tickets, wallets, credit cards, hair clips and any other metal objects.
Before the scan, we will need to know your child’s weight and height. Most patients will have an intravenous (IV) contrast dye called gadolinium for some of the pictures during the scan. This flows through your child’s blood vessels, making them show up on the scan more clearly. We will insert a cannula into a vein (usually in your child’s arm) before the scan takes place.
We can put some local anaesthetic cream on the area first to make inserting the cannula more comfortable. The cannula will be removed again after the scan, before you go home.
What happens during the scan?
We will help your child into the scanning room and onto the bed, making them as comfortable as possible. We will put ECG leads on the skin of your child’s chest and a light, rectangular plastic device containing receiver coils over these leads.
We will give your child earphones to wear, as the scanner makes a loud knocking noise during the scan. Your child can watch a DVD during the scan. You can bring your own DVD or we have a selection of DVDs from which you can choose.
A radiographer will operate the MRI machine from the room beside the scanning room, but he or she will talk and listen to your child through an intercom and watch them through a large glass window. While the scan is happening, your child will need to relax and lie as still as possible. We will give your child instructions about holding his or her breath for some of the pictures.
How long will the scan take?
The scanning time is usually between 45 minutes and one hour.
Can anyone go into the scanning room?
If you or your partner is able to go into a strong magnetic field and has been through our metal object safety check, you can then stay inside the scanning room with your child. You will also need to wear earphones for protection during the scan, but can sit near your child’s head or feet to keep him or her company while the scanning is happening.
What happens afterwards?
When the MRI scan is finished, your child will be able to get dressed and leave. Many families will need to return to other parts of the Cardiac Unit for other tests. The cardiac MRI specialist will review the images and report the results to your child’s cardiologist. He or she will contact you about the results and any outpatient appointments needed.
Last reviewed by Great Ormond Street Hospital: September 2012
Ref: 2012F0045 September 2012
Compiled by the Cardiac MRI team in collaboration with the Child and Family Information Group.
This information does not constitute health or medical advice and will not necessarily reflect treatment at other hospitals. If you have any questions, please ask your doctor. No liability can be taken as a result of using this information.