Cardiac MRI Scan

During a cardiac MRI, a narrow beam X-ray will rotate around the area that's been scanned. The high-strength magnet and radio waves that are used generate pictures of internal organs and structures, which are then produced on a computer screen. This type of scan can also show a doctor how well blood is moving throughout the heart area.

The X-ray beam takes multiple images through the scan, and these images are taken in extremely quick succession and from multiple angles. Once the pictures are taken, computer programs have the ability to link these images up to produce a 3D image for the technician to use to diagnose the condition.

Unlike X-rays, an MRI doesn't use radiation. Instead, it harnesses radio waves from data that already exist in the body, meaning it won't cause chemical change or damage to tissue.

Sometimes, technicians use a contrast agent when conducting cardiac MRI scans. This means that the recipient of the scan will be administered a contrast dye, usually through IV or barium meal. The dye helps produce clearer images of internal organs and tissues and assists doctors to detect certain issues.

A Cardiac MRI will almost always need to be ordered by a referring physician. If a doctor detects that the patient may have a condition that can be detected with an MRI, they will recommend a cardiac MRI.

If you are experiencing any of the following issues, you may be referred for a cardiac MRI: shortness of breath in the chest; pain in the chest; weakness, light-headedness or nausea; pain or discomfort in the arms or shoulder; or heart palpitations.

Below are a number of conditions that a cardiac MRI scan can help diagnose: an enlarged heart; coronary artery disease; heart failure; heart muscle damage, inflammation, infiltration and infection; heart valve disease; heart disease; cancer and other masses; and heart defects.

A cardiac MRI is a non-invasive test and won't require much preparation in the lead up to your scan. Patients are usually able to eat and drink as normal up until their scan. However, it's always a good idea to check with the referring technician if there are any special requirements, as some scans may be slightly different. For example, patients who are having an MRI with a contrast agent, or who are claustrophobic and will be sedated, may be required to stop eating and/or drinking for a certain period before the scan.

All MRIs require patients to remove all metal objects from their body. This includes things like jewellery, piercings and a watch. While it's possible to remove these items at the clinic, it's a good idea to take them off before you leave home to save some time.

If a patient has a metal object implanted in their body — like a hearing aid or pacemaker — it's very important that they let their technician know prior to the scan.

When you arrive for your scan, a receptionist will check you in like a normal doctor's appointment. Once the technician is ready for your scan you will be taken to a room where you'll find a large tubular machine — this is the MRI machine.

For a cardiac MRI, you'll be asked to change into a hospital gown, and a technician or radiologist will have a quick consultation with you to answer any questions you may have. If your scan requires a contrast agent, the physician will administer it before the scan.

Once you've changed into your gown the technician will ask you to lie on a thin metal table, and adjust your body into a position so that the scan can clearly capture the required images. You'll almost always be fitted with earphones and a buzzer — these tools allow you to speak to the physician while you're in the scan, and the earphones can also help to block out the loud noises.

The technician will then slide the table into the MRI machine. These machines are usually loud and dark, so if you're claustrophobic you should inform your technician prior to the scan. The scan itself should only take a few minutes, and it's very important to stay completely still, as even the smallest movement can blur the image. Once the scan is completed, the physician will slide you out of the MRI machine and you'll be able to continue your day as normal.

After the scan, patients shouldn't feel any different unless they have had a sedative for claustrophobic purposes. In very rare cases, patients can be allergic to MRI contrast dye — if you notice any allergic reactions like a rash or hives, contact a doctor immediately. Results are usually available about a week after the scan, though urgent cases can be prioritised.

Cardiac MRI scans can identify issues with soft tissues within the heart which traditional X-rays can't. The preciseness of an MRI means they are able to pick up very small abnormalities that may not otherwise be evident. MRIs are non-invasive and don't involve any radiation, meaning they are a very safe procedure. The results are quick, which means that treatment can be started promptly.

There are a variety of conditions that, if a doctor suspects, may lead them to order an MRI for your heart. Some of these include heart disease, heart failure, and heart defects. A doctor may also use a cardiac MRI to monitor existing conditions, diseases or defects.

A patient should allocate about 45 minutes for a cardiac MRI appointment. However, this can vary greatly if a sedative or a contrast agent is used. While the appointment usually takes a little under an hour, this includes preparation time — the scan itself generally only takes a few minutes.

Generally, yes. Cardiac MRIs are relatively accurate in showing cardiac blockages in large sections of the coronary organs. However, they may miss blockages in smaller organs. If a physician detects a blockage, they may order a test called a CT coronary angiogram.

Cardiac MRIs are non-invasive and shouldn't cause any discomfort. However, some patients may feel discomfort during the process of the scan due to having to lie still in the same place while images are being taken, as well as the loud noise and dark tube.

Not necessarily. A doctor will conduct a physical exam and speak with you about your symptoms. If they suspect a condition that a cardiac MRI will be able to detect, then they will refer you for a scan.