MRI and MRA scans are both types of diagnostic imaging tests that help doctors and consultants diagnose (and potentially rule out) a wide range of diseases and conditions affecting various different parts of the body. The process for both types of medical imaging scan is very similar, but doctors will choose whether to perform an MRA vs MRI depending on your symptoms and what part of the body they’d like to take a detailed look at.
Many people have heard of an MRI scan, but you may not be familiar with an MRA scan. In this article, we’ll discuss everything you need to know about MRA vs MRI scans including the differences, similarities and why you might need to have one.
What Is an MRI?
MRI stands for magnetic resonance imaging. An MRI scan is a type of diagnostic imaging test that uses radio waves and a strong magnetic field to create detailed images of the inside of the body including the bones, tissues and organs.
How an MRI Works
The body is predominantly water, which contains hydrogen atoms. An MRI scan uses a strong magnetic field to cause these hydrogen atoms to line up and then radio waves to scatter them again.
During an MRI scan, the magnetic field and radio waves are turned on and off to move the hydrogen atoms around, which creates energy that’s picked up by a computer and turned into an image. It can detect differences between bone, organs and soft tissue, and abnormalities such as tumours, breaks and inflammation. You won’t feel anything throughout the scan, which will last between 30 and 90 minutes.
In some cases, a contrast dye will be injected into a blood vessel in your arm or groin. This allows certain abnormalities to show more clearly on the image.
Preparing for Your MRI
Your medical team will inform you if you need to avoid eating or drinking prior to your scan. In some instances, you will be asked to drink a lot of water beforehand, depending on the area being scanned.
Due to the use of strong magnets, you will also need to remove any metal piercings, hearing aids and other removable implants and leave anything metal, including keys, bank cards and your mobile phone outside of the scanning room. If you have any metallic implants that cannot be removed, or tattoos that contain metal, let your medical team know and they can make alternative arrangements if necessary.
What Is an MRA?
MRA stands for magnetic resonance angiography (sometimes referred to as a magnetic resonance angiogram or an angiography MRA) and is a type of MRI scan. However, an MRI scan looks at the bones, spine, muscles, nerves, brain, organs and tissues, and an MRA scan looks specifically at the blood vessels.
A traditional angiogram involves inserting a catheter into a blood vessel to give doctors an idea of how healthy it might be. This is an invasive procedure and can be painful. An MRA scan is a non-invasive, pain-free alternative to an angiogram.
How an MRA Works
An MRA scan works in much the same way as an MRI scan and will usually involve the use of a contrast agent injected into a blood vessel in your arm or groin. It focuses on the blood vessels in different parts of the body, and the contrast dye highlights any blockages, narrowing or abnormalities more clearly on the MRA image.
Preparing for Your MRA
Preparation for an MRA scan is the same as for an MRI scan, including the removal of any metals from your body, and discussing any that can’t be removed.
MRA vs. MRI: Definitions
An MRI, or magnetic resonance imaging scan looks inside the body at the muscles, bones, brain, spine, spinal cord, tissues and organs.
An MRA, or magnetic resonance angiography scan also looks inside the body, but specifically at the arteries and veins (known collectively as the blood vessels).
Both scans may also use a contrast dye to make the areas of interest stand out more clearly on the images produced, but this dye is more likely to be used during an MRA than an MRI. An MRA scan is often performed at the same time as an MRI, for example, to diagnose a stroke or heart disease that requires a detailed look at both the organ (i.e. the brain or the heart) as well as the blood vessels supplying it.
MRA vs. MRI: Similarities and Differences
An MRI scan and an MRA scan are similar types of diagnostic imaging tests that use the same technology and equipment to produce detailed images of various body parts. Although they’re similar, there are some differences, too.
How Are MRAs and MRIs Similar?
Here are the similarities between MRA vs MRI scans:
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Both MRA and MRI scans are carried out in an MRI machine to look inside the body
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They both utilise short bursts of radio waves and a strong magnetic field to produce detailed images of different body parts
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Both are considered a non-invasive, pain-free type of diagnostic imaging test
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Unlike CT scans and X rays, neither use radiation and are therefore considered the safest type of scan for most people
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Both may be unsuitable for anyone who has magnetic metal inside their body, such as piercings and implants that cannot be removed, due to the strong magnets used in the MRI scanner
How Are MRAs and MRIs Different?
The main difference when considering an MRA vs MRI scan is the part of the body that’s being scanned. MRI scans are used to take detailed images of the bones, nerves, organs and tissues while an MRA scan is used solely to look at the blood vessels and blood flow, and sometimes the organs and tissues (such as the heart and brain) immediately surrounding them.
An MRI scan tends to scan large parts of the body, or the entire body. An MRA scan usually only looks at a certain blood vessel.
MRA vs. MRI: Uses for Each Procedure
MRI and MRA scans both prove useful in various different health investigations, and as such, they’re used very commonly in hospitals and clinics in order to diagnose a wide range of conditions.
What Does an MRA Show?
An MRA will highlight:
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Blood clots
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Narrowing or blockages in the blood vessels
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Weaknesses in the walls of the blood vessels
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Problems with blood flow
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A brain aneurysm
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Heart disease
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The cause of a stroke or heart attack
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Deep vein thrombosis (DVT)
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Problems with the blood vessels supplying blood to the kidneys
What Does an MRI Show?
An MRI will show abnormalities such as breaks, tears, tumours, infections and inflammation in the bones, organs and tissues.
When Do Healthcare Professionals Use MRAs?
Your doctor or specialist will recommend that you have a magnetic resonance angiography scan if they suspect you may have a narrowing or a blockage in a blood vessel somewhere in your body, including the blood vessels that feed the brain and the heart.
You may also have an MRA scan before having heart or brain surgery so that they understand exactly where your blood vessels are, or before having heart bypass surgery where a blood vessel from elsewhere in the body is removed and used to graft into a diseased one in the heart.
When Do Healthcare Professionals Use MRIs?
If your medical team suspect you may have one of the following, they may perform an MRI scan:
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Joint injury affecting the bones, muscle, cartilage or connective tissue (ligaments and tendons)
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Arthritis
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Other types of damage such as breaks or tears
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Cancerous or benign tumours and growths
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Injury to the spinal cord, column or discs
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Brain injury
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Infection or injury to the inner ear or eye
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Inflammatory bowel conditions such as Crohn’s disease
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Alzheimers’ disease
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Multiple sclerosis
Why You Might Need an MRI
Here’s a more detailed look into why you might need an MRI scan…
Brain and Central Nervous System (CNS)
MRI scans, often in conjunction with an MRA, are an important diagnostic tool for diagnosing strokes and brain aneurysms, as well as conditions that affect the CNS (the spinal cord and nerves) such as degenerative disc disease and an annular tear.
Cardiovascular System
A cardiac MRI scan looks at the heart and surrounding tissues to diagnose conditions such as heart failure and diseases of the valves and to check for damage following a heart attack.
Abdominal
An MRI of the abdomen is used to detect and diagnose conditions affecting the bowel and gastrointestinal tract. These include Crohn’s disease, bowel cancer and blockages in the bile duct that can lead to gallstones.
Pelvic Organs
MRI scans are routinely used to diagnose problems affecting the uterus, ovaries and fallopian tubes in women and the prostate and testicles in men. A pelvic MRI can also be used to look at the bladder and rectum.
Musculoskeletal System
An MRI scan is capable of detecting soft tissue injuries, bone fractures and inflammation, more so than a CT scan or an X ray can. If you have a suspected ligament or muscle tear, a broken bone or unexplained pain that could be due to inflammation (such as in the case of arthritis), an MRI scan will be useful in order to get a diagnosis and treatment plan.
Breasts
MRI scans are used along with mammograms, biopsies and other tests to confirm or rule out breast cancer. An MRI scan can provide essential information on where any breast tumours are located and what size they may be.
Abnormalities
Often, abnormalities anywhere else in the body, such as pain, swelling, lumps and areas of tenderness can only be diagnosed with an MRI scan.
Why You Might Need an MRA
Your doctor will suggest an angiography MRA scan if they need to see detailed images of your blood vessels and the rate of your blood flow. There are various reasons why this might be…
Brain and Central Nervous System
Crucially, an MRA scan (along with an MRI scan) can help doctors diagnose a stroke or brain aneurysm that affects the blood vessels of the brain. They can also diagnose atherosclerotic disease, where plaque builds up in the blood vessels making them ‘sticky’ that could eventually lead to a stroke.
Cardiovascular System
MRA scans can be used to diagnose (or rule out) conditions affecting the heart and blood vessels, including:
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Blood clots
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Coronary heart disease
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Blockages or narrowing in the blood vessels leading to and from the lungs
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Damage or injury to the blood vessels
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Abnormalities in the blood vessels that are present at birth
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An aneurysm in another part of the body such as the chest or abdomen
An MRA scan can also indicate if your blood flow is moving too fast or too slowly. If your blood flow is too fast, it may suggest that you have high blood pressure that could lead to heart disease or strokes. Slow blood flow could indicate low blood pressure that could be as a result of a blockage that could cause a heart attack.
You may also have an MRA if you’re due to have surgery and your surgeon needs to know exactly where your blood vessels are located.
Extremities
Pain or swelling in the arms and legs is usually thought to be caused by muscle or soft tissue injury, perhaps due to sports and exercise. However, it could also be due to a problem with the blood vessels, for example deep vein thrombosis or peripheral artery disease. Unexplained pain in the extremities could therefore be caused by a blocked or narrowing blood vessel that can be confirmed via an MRA scan. .
Renal System
The renal system describes the kidneys, ureters, bladder and urethra, and is more often referred to as the urinary tract. An MRA scan can be useful for diagnosing a condition called renal artery stenosis that’s caused by a narrowing of the blood vessels of the kidneys and can lead to renal failure.
How Are MRIs and MRAs Performed?
MRI and MRA scans are performed in a machine called an MRI scanner. You will be required to lay completely still on a flat bed that moves into the scanning machine - the whole process will take between roughly 30 and 90 minutes.
If you’re unable to remain still, speak to your doctor who may be able to suggest an alternative type of imaging test. Likewise, if you think you’ll struggle being in the confined space of the MRI scanner or you have claustrophobia, speak to your medical team. They may be able to give you a mild sedative medication that will help to calm your nerves.
MRI and MRA Risks
MRI and MRA scans are considered safe for most people, mainly because they don’t use radiation. However, there are some very small risks associated with both and include:
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Skin heating and/or burning
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Damage to your hearing
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Reactions to magnetic metal in your body such as piercings or medical implants
These risks are very small, and your medical team will take steps to mitigate them including the use of heat absorbing pads to lay on, headphones or ear plugs and discussing any metal that you may have in your body beforehand.
Since both types of imaging test can potentially be carried out using a contrast dye, there are some small risks associated with this too. This includes the normal risks associated with having an injection or intravenous drip such as bruising and bleeding. The dye may also cause a metallic taste in the mouth and nausea. But it can also cause a more serious allergic reaction if you have kidney disease. If you do, or you have a known allergy to contrast dyes, let your medical team know beforehand.
How to Choose Between an MRA and MRI
It will be up to your medical team whether you have an MRA vs MRI scan, and it will depend on your symptoms and what they think might be the possible cause. If you’re concerned about anything to do with your health, the sooner you get it checked out, the sooner you can start any necessary treatment or gain peace of mind.
It’s helpful to prepare a few notes regarding your symptoms including when they started, what might cause them to feel worse and what might relieve them, ready for when you speak to your doctor.
Find a Private MRI Scan
Having any kind of scan or diagnostic test can feel daunting, but we’re here to help. Book a private MRI scan with us and we’ll ensure you get the tests you need. If you’re unsure if an MRA vs MRI scan is right for you, book an appointment to see one of our private consultants who can help you navigate your way through your journey to getting the medical treatment you need.
References
Sawyers, T. (2018, August 23). MRI vs. MRA: What Is the Difference? Healthline. https://www.healthline.com/health/mri-vs-mra
Professional, C. C. M. (2024c, December 19). MRA. Cleveland Clinic. https://my.clevelandclinic.org/health/diagnostics/24024-mra
MRA vs. MRI: What Are the Differences and Uses? (2021, September 3). AdventHealth University. https://www.ahu.edu/blog/mra-vs-mri
Brain Aneurysm Foundation. (2025, January 3). MRA vs. MRI - Brain Aneurysm Foundation. https://www.bafound.org/blog/mra-vs-mri/
