About an MR angiogram of the arm
An MR angiogram (MRA) is a type of MRI scan that focuses on blood vessels. It uses a strong magnetic field, radio waves and a computer to make detailed pictures of the arteries, and sometimes the veins, without X-rays. Unlike a traditional (catheter) angiogram, no tube needs to be passed into an artery.
An MRA of the arm looks at the blood vessels running from the shoulder area down towards the hand. It is used to look for narrowing, blockages, swellings (aneurysms) or abnormal connections in these vessels, and to help plan treatment. Left and right arms are separate scans, so choose the side you need when you book.
Referral needed: this scan requires a referral from a specialist, such as a vascular surgeon or other hospital consultant. You can upload the referral when you book.
What happens during the scan
You lie on your back on the scanner bed with a coil placed around your arm. The scanner is loud, so you will wear ear plugs or headphones, and the radiographer can see, hear and talk to you throughout. You will need to keep your arm very still, as even small movements can blur the pictures of the blood vessels.
Most MR angiograms use an injection of contrast dye (gadolinium) through a small cannula in a vein, usually in your arm or hand, so the blood vessels show up clearly. Gadolinium is less likely to cause an allergic reaction than the iodine-based dye used for CT. Some vessels can also be imaged without contrast. If you have contrast, you may be asked to wait for up to 30 minutes afterwards. Where contrast is needed, it is charged separately.
If your specialist suspects that the blood vessels are being squeezed when you move your arm (for example in thoracic outlet syndrome), some pictures may be taken with your arm in different positions, such as raised above your head.
What the scan can show
An MR angiogram of the arm can help to look at:
- narrowing (stenosis) or blockage of the arteries in the arm
- swelling or bulging of an artery (aneurysm)
- abnormal connections between arteries and veins (vascular malformations)
- arteries being compressed when the arm moves, as in thoracic outlet syndrome
- damage to blood vessels after an injury
- blood vessels before surgery, or after treatment such as a stent or bypass
MRA does not show calcium in the artery walls, and very small vessels in the hand can be hard to see clearly. Your specialist will advise whether MRA or another test, such as an ultrasound or CT angiogram, is best for you.
Preparing for your scan
No special preparation is usually needed. Because most MR angiograms use contrast dye, let us know when you book if you have kidney problems or have had a reaction to contrast before.
You can usually eat, drink and take your normal medicines unless the scanning centre tells you otherwise. Wear loose, comfortable clothing without metal zips or buttons, and leave jewellery at home. You will be asked to remove metal items such as hair clips, hearing aids, coins and keys, and you may be asked to change into a gown.
Before the scan you will complete a safety questionnaire. Tell the team if you have a pacemaker, any metal implant, surgical clips or other device, if you have kidney problems or allergies, or if you are, or might be, pregnant or breastfeeding. If you feel anxious in enclosed spaces, let us know when you book. Some centres can offer a relaxant, and if you take one you will need someone to take you home and must not drive for 24 hours.
Frequently asked questions
Do I need a referral for an MR angiogram of the arm?
Yes. This scan requires a referral from a specialist, such as a vascular surgeon or consultant. Please upload your referral when you book so the scanning centre can check that the right scan is arranged.
How is an MR angiogram different from a normal angiogram?
A traditional angiogram involves passing a thin tube (catheter) into an artery and using X-rays. An MR angiogram uses an MRI scanner and usually an injection into a vein in your arm, so there is no catheter and no radiation.
Will I need a contrast injection?
Usually, yes. Contrast dye helps the blood vessels show up clearly. It is given through a small cannula and is charged separately where it is needed.
Can both arms be scanned at the same appointment?
Each arm is a separate scan. If your referral is for both arms, book both sides together; two or more areas booked together qualify for the lower clubbed price.
Sources
- RadiologyInfo.org – Magnetic Resonance Angiography (MRA)
- Balkan Medical Journal (2011) – MR angiography in thoracic outlet syndrome
- NHS – MRI scan
The information on this page has been gathered from various sources and is provided for general information only. It is not medical advice. TOP MRI is not liable for the accuracy or completeness of this information. Please speak to your doctor or the scanning centre about your own situation.