Cardiac Magnetic Resonance Imaging – Cardiac MRI – is one of the most advanced and accurate ways to look at the heart in great detail. If you’ve been told you need a cardiac MRI, you may have questions: What is it? Why do I need it? Is it safe? What happens during the scan?
In this post, I will walk you through everything you need to know about this powerful diagnostic test, what to expect, and how it helps us understand your heart health.
What is Cardiac MRI scan?
A Cardiac MRI is a specialised scan that uses strong magnetic fields and radio waves to create detailed images of your heart and blood vessels – without using X-rays or radiation.
Unlike a standard MRI that focuses on bones or the brain, a cardiac MRI is specifically tailored to capture the structure, function, and tissue characteristics of the heart. It gives us a three-dimensional view and allows us to see your heart beating in real-time, measure blood flow, assess damage from previous heart attacks, and detect inflammation, scarring, or congenital heart abnormalities.
Indications for Cardiac MRI
Cardiac MRI is used when we need a more detailed picture than what an echocardiogram (ultrasound of the heart) or CT scan can provide. It’s particularly useful for:
- Diagnosing heart muscle diseases (like cardiomyopathy)
- Evaluating inflammation or infection of the heart (myocarditis or pericarditis)
- Assessing damage after a heart attack (myocardial infarction)
- Checking for scar tissue or fibrosis in the heart muscle
- Detecting tumours or congenital abnormalities
- Understanding heart valve problems
- Measuring heart function in very precise detail
It’s also commonly used in patients with unexplained chest pain, breathlessness, or abnormal heart rhythms, especially when other tests are inconclusive.
What is Stress Cardiac MRI?
A Stress Cardiac MRI is a detailed heart scan performed while your heart is under controlled stress – usually using medication rather than exercise. It allows us to see:
• Whether parts of your heart muscle aren’t getting enough blood.
• If there’s any scarring or previous damage.
• How well your heart is pumping overall.
This test gives your cardiologist a clear picture of whether any narrowed or blocked arteries are affecting your heart function. It can guide the decision whether further intervention including coronary stents or open heart surgery is required.
Is Cardiac MRI Safe?
Yes – cardiac MRI is very safe for most people. It doesn’t use ionising radiation like a CT scan or X-ray, so there’s no radiation risk.
However, it’s not suitable for everyone. You may not be able to have an MRI if you have:
- Certain types of pacemakers or defibrillators
- Metal implants or fragments (especially in the eye or brain)
- Severe kidney disease (if a contrast agent is required)
Before the scan, we’ll ask detailed questions about your medical history and any implants you may have to ensure the procedure is safe for you.
What Happens During a Cardiac MRI?
- Preparation
You’ll be asked to change into a hospital gown and remove all metal objects (including jewellery, belts, glasses, and underwire bras). We may place ECG leads on your chest to monitor your heart rhythm during the scan.
- Contrast Agent
In many cases, a contrast dye called gadolinium will be injected into a vein in your arm. This helps highlight areas of inflammation or scarring. It’s generally well-tolerated and very rarely causes allergic reactions.
- The Scan
You’ll lie flat on a table that slides into the MRI scanner – a large, tunnel-shaped machine. The scan is painless but can be noisy, so you’ll be given headphones or earplugs. You’ll need to lie very still, and at times, you may be asked to hold your breath for a few seconds.
- Duration
A cardiac MRI typically takes 30 to 60 minutes, depending on the complexity of the scan.
- After the Scan
Once the scan is complete, you’ll be able to go home right away. There’s no recovery time unless you’ve received a sedative (rarely needed). The images will be analysed by a cardiac imaging specialist, and the results will be sent to your referring cardiologist for further discussion.
What Are the Benefits of Cardiac MRI?
Cardiac MRI offers several advantages:
- Highly accurate for diagnosing heart conditions
- Non-invasive and painless
- No radiation exposure
- Provides detailed information that other tests may miss
- Can guide treatment decisions and monitor progress over time
It’s considered the gold standard for assessing heart muscle and function in many cases.
Frequently Asked Questions
Is the test uncomfortable?
Most people tolerate the scan well. If you have specific fears of enclosed spaces – claustrophobic, let us know – we can take steps to make you more comfortable. Alternatively, your cardiologist can refer you to an alternative imaging modality.
Is the contrast dye safe?
Yes. Gadolinium is usually very safe, especially in patients with normal kidney function. We’ll check your kidney function beforehand if needed.
How long until I get results?
Results are typically available within a few days. Your cardiologist will go over them with you and explain what they mean.
Final Thoughts
A cardiac MRI is one of the most informative tests we have in modern cardiology. Whether we’re investigating symptoms, monitoring a known condition, or planning treatment, this scan can give us crucial insights into how your heart is functioning and help us provide the best possible care.
Author’s biography
Dr Ahmed Kharabish
- MSc, MD/PhD, CESR, Facharzt
- Consultant Cardiac Radiologist
- Associate Professor of Radiology
- SCMR Level III
- EACVI Congenital MRI Level III
- BSCI BSCCT Level II
Dr. Kharabish has received his Masters and MD/PhD Degree in radiology from Cairo University, Egypt in 2009 and 2016 respectively. Currently he holds the position of an associate professor of radiology (on leave), Cairo University.
In 2014, he obtained a clinical fellowship in cardiac imaging in the German Heart Centre, Munich, Germany. Later in 2017 successfully obtained the German Board of Radiology (Facharzt). He has worked as the head of the Radiology Department in Aswan Heart Centre, Egypt with Sir Prof. M. Yacoub years and also successfully led the radiology department at Liverpool Heart and Chest Hospital until December 2024. Currently he continues to work as a consultant of cardiac imaging in Liverpool Heart and Chest Centre, United Kingdom. In addition to receiving the Level III training certificate from the SCMR in 2014, he has received level III certificate of Congenital Heart Disease CMR from the European Association of Cardiovascular Imaging (2018) and Level II in cardiac CT from the British Society of Cardiovascular Imaging.
Dr. Kharabish conducted many presentations at various national and international cardiac imaging conferences as well as authored and co-authored many valuable publications in the field of cardiac imaging as well as admin and manges an educational free youtube channel in cardiovascular imaging.
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