Magnetic resonance imaging (MRI) is a type of scan that takes detailed pictures of the inside of the body. Cardiac MRI is a scan of the heart and blood vessels. It is safe and painless.
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Why Have a Cardiac MRI?
A cardiac MRI scan is done using an MRI machine, which uses magnets and radio waves to create detailed pictures of the inside of the heart. A cardiac MRI is used to find out:
A cardiac MRI scan also looks at the blood supply to the heart, which allows your doctor to see:
Preparing for a Cardiac MRI
The strong magnets used during the scan may affect metal in your body. If you have any of the following symptoms, please let the MRI department know as soon as possible:
- Medical implants such as pacemakers, implantable cardioverter defibrillators (ICDs), electrocardiogram measuring devices, and loop recorders (electrocardiogram monitors)
- Coronary Artery Stents
- Heart valve surgery (mechanical valve replacement)
- Other metals in the body.
Most people with medical implants such as pacemakers or ICDs can have an MRI scan. It is important that your doctor checks your device before you have a scan.
Please inform the hospital if:
- Afraid of small spaces (claustrophobia)
- Are pregnant or possibly pregnant
- If you have COPD or asthma and use an inhaler
- you If you have a history of kidney disease, see us for contrast agents (dyes).
- Weighing over 102kg (16 stone).
MRI machines are not available at all hospitals, so you may have to travel to another hospital for your scan.
On the day of your scan, please prepare as follows:
- Remove electronic devices and debit and credit cards from your pockets
- Remove metal objects such as belts, jewelry, earrings, watches, and hearing aids.
- Avoid applying oils or lotions to your skin
- Avoid smoking.
If you have particularly thick chest hair, you may need to shave it before you arrive, as they will be placing adhesive pads on your chest to check your heart rate.
Before your scan, you can eat, drink, and continue to take your usual medications as usual, unless otherwise advised. You may be asked to avoid caffeine for a short while before your scan.
You won’t have to worry about forgetting any of these as they will be checked several times during your stay.
During cardiac MRI
This video explains what to expect, but it may not be the same at every hospital.
- The scan lasts between 15 and 90 minutes and is painless. Here’s what to expect during the test:
- You will be asked to lie on a moving bed inside a tunnel-shaped scanner, which is open on both ends.
- You will be asked to lie still while the scan is being done, and you may be asked to hold your breath for a moment.
- A small device may be placed on your chest or abdomen to get clearer pictures.
- A blood pressure cuff may be placed on your arm to check your blood pressure during the procedure.
- The scan will last up to 90 minutes, but you can press a buzzer if you need to speak to the person operating the scanner (the radiologist).
- The scanners are quite noisy – you may hear loud banging noises while being scanned – you can usually wear earplugs or listen to music with earphones.
If you have a fear of tight spaces, tell your doctor before the procedure, as he or she may prescribe a mild sedative to help you relax.
Infants
Babies and young children may be given anesthesia before having an MRI scan, as it is important that they do not move during the scan.
If your baby or child needs to have a cardiac MRI scan, you may be worried about what it means and what will happen during the test. Ask your doctor for more information about what the test involves. You can also call the Cardiac Helpline to speak to a specialist cardiac nurse.
Contrast agents (dyes)
You may be injected with a dye (contrast material), which helps the scan show a clearer picture of blood flow to your heart. The dye is injected into a vein in your arm on the same day as your MRI scan. After your scan, you will usually need to drink plenty of fluids to help the dye leave your body through your urine.
Your doctor can give you more information on this.
If your kidneys are not working well, the dye used during the scan may cause further damage to your kidneys. Your doctor may do blood tests before the scan to check your kidney function and explain the risks and benefits. In some cases, the amount of dye used may be reduced. In rare cases, if you have kidney problems, you may need to be given a ‘drip’ into a vein in your arm to keep you hydrated before the MRI scan.
Cardiac MRI Stress Test
Your doctor may have you undergo a cardiac MRI stress test, which is a test to see how well your heart works when it has to work a little harder than usual.
A cardiac MRI stress test is different from an exercise ECG (stress test), which looks at how your heart works during exercise. With an MRI stress test, you receive medicine through a vein in your arm to make your heart beat faster. This shows how your heart works when it’s under stress (like exercise). A radiologist or cardiac radiologist will be with you during the test.
The test is safe and painless. You may feel some effects from the medication, such as shortness of breath or a sudden hot flash. These effects stop soon after the medication is administered, as the medication only stays in your body for a short time.
After Cardiac MRI
You usually won’t need to stay in hospital overnight after a cardiac MRI, and you can return to your normal activities straight away.
There are a few exceptions to this:
- If you are sedated, you will need a friend or relative to drive you home. You will be asked to refrain from drinking alcohol, driving, or operating machinery for 24 hours.
- If you have been injected with contrast (dye), you should drink plenty of water for 24 hours after your scan to help flush the dye from your body.
The doctor who arranged your scan will usually discuss the results with you when they are ready and a report will be sent to your GP.
Many people feel worried or anxious during this time. There is no right or wrong way to deal with these feelings; it’s different for everyone. Continuing with daily activities, like going to work or spending time with loved ones and pets, can serve as a distraction. Talking to your partner, family, or close friends may also help.
More information and support
If you require any more information or would like to speak to someone, please feel free to contact us.
