About an MR angiogram of the neck
Four main arteries run through your neck to supply the brain: the two carotid arteries at the front and the two vertebral arteries at the back. An MR angiogram (MRA) of the neck uses a strong magnetic field, radio waves and a computer to make detailed pictures of these arteries, without X-rays and without passing a tube (catheter) into an artery.
The scan is most often used to look for carotid artery disease, which is narrowing of the carotid arteries caused by a build-up of fatty material (atherosclerosis). Narrowing reduces blood flow and raises the chance that a small piece of fatty material breaks off and travels to the eye or brain, causing a stroke or a transient ischaemic attack (TIA, or “mini-stroke”). Finding and measuring the narrowing helps your specialist decide on treatment, which may include medicines or an operation to remove the fatty material (carotid endarterectomy).
Referral needed: this scan requires a referral from a specialist, such as a vascular surgeon, stroke physician 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 head and neck. 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 head and neck 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.
What the scan can show
An MR angiogram of the neck can help to look at:
- narrowing (stenosis) or blockage of the carotid arteries, and how severe it is
- narrowing of the vertebral arteries at the back of the neck
- a tear in the wall of a neck artery (dissection)
- aneurysms and other abnormalities of the neck arteries
- the arteries before or after surgery or stenting
MRA does not show calcium in the artery walls as clearly as a CT angiogram, and a neck ultrasound (duplex scan) is often used as well. Your specialist will advise which tests suit you best.
Stroke is an emergency. Remember FAST: Face drooping on one side, Arm weakness or numbness, Speech slurred or confused, Time to call 999. Call 999 even if the symptoms go away. Do not wait for a scan.
Preparing for your scan
No special preparation is usually needed, and you can eat and drink normally. If you have had a previous neck ultrasound or brain scan, upload the report when you book so it can be compared.
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 neck?
Yes. This scan requires a referral from a specialist. Please upload your referral when you book so the scanning centre can check that the right scan is arranged.
Why is narrowing of the carotid artery important?
Narrowing of a carotid artery reduces blood flow to the brain and can allow small pieces of fatty material to break off and travel to the brain or eye. This increases the risk of a stroke or TIA. Measuring the narrowing helps your specialist decide whether you need medicines or surgery.
Will I need a contrast injection?
Sometimes. Neck MRA can be done with or without contrast, depending on what your specialist needs to see. If contrast is used, it is given through a small cannula in your arm and charged separately.
How is an MR angiogram different from a normal angiogram?
A traditional (catheter) angiogram involves passing a thin tube into an artery, usually from the groin or wrist, and uses X-rays. An MR angiogram uses an MRI scanner, with at most an injection into a vein in your arm, so there is no catheter and no radiation.
Sources
- NHS – Carotid endarterectomy: why it’s done
- NHS – Stroke symptoms
- RadiologyInfo.org – Magnetic Resonance Angiography (MRA)
- 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.