About an MR angiogram of the brain
An MR angiogram (MRA) of the brain is an MRI scan that focuses on the blood vessels inside the head. It uses a strong magnetic field, radio waves and a computer to make detailed pictures of the arteries without X-rays and without a catheter. Brain MRA can often be done without a contrast injection, using the natural movement of blood to create the pictures, although contrast is sometimes added.
One of the most common reasons for a brain MRA is to look for, or keep an eye on, a brain aneurysm. This is a swelling in a blood vessel in the brain. Most are small, cause no symptoms and are found by chance on scans done for another reason. Your doctor may suggest a scan if you have a close family history of brain aneurysm, or a condition linked to aneurysms such as autosomal dominant polycystic kidney disease (ADPKD), or to monitor the size of a known aneurysm. Brain MRA is also used to look at narrowed arteries and abnormal tangles of blood vessels (arteriovenous malformations).
Referral needed: this scan requires a referral from a specialist, such as a neurologist, neurosurgeon, vascular surgeon or other hospital consultant. You can upload the referral when you book.
What happens during the scan
You lie on your back with your head in a head coil, which fits around your head like a cage, with a mirror so you can see out. The scanner is loud, so you will wear ear plugs or headphones, and the radiographer can see, hear and talk to you throughout. You need to keep your head very still. If contrast dye (gadolinium) is needed, it is given through a small cannula in your arm and charged separately, and you may be asked to wait for up to 30 minutes afterwards.
What the scan can show
An MR angiogram of the brain can help to look at:
- brain aneurysms, including checking the size of a known aneurysm over time
- narrowing or blockage of the arteries inside the head
- arteriovenous malformations (AVMs), which are abnormal tangles of arteries and veins
- the blood vessels before or after treatment, such as coiling or clipping of an aneurysm
- blood vessel abnormalities present from birth
Very small blood vessels can be hard to see on MRA. Your specialist will advise whether MRA, a CT angiogram or a catheter angiogram is best for you.
Emergency symptoms: a sudden, extremely severe headache (often described as the worst headache ever), drooping of one side of the face, weakness in an arm or one side of the body, problems speaking or sudden loss of vision can be signs of a bleed or stroke. Call 999 straight away. This is not a reason to wait for a scan.
Preparing for your scan
No special preparation is needed for most brain MR angiograms, and you can eat and drink normally. If you have had a previous 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 brain?
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.
Can an MR angiogram find a brain aneurysm?
Yes. MR angiography is commonly used to look for brain aneurysms and to monitor the size of a known aneurysm. Very small aneurysms can be harder to see, so your specialist may recommend another test in some cases.
Will I need a contrast injection?
Often not. Brain MRA can usually be done without contrast. If your specialist asks for contrast, 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
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.