Cerebral angiography is a test that uses X-rays and a special dye to create pictures of the blood vessels that supply the brain.
Note: the information below is a general guide only. The arrangements, and the way tests are performed, may vary between different hospitals. Always follow the instructions given by your doctor or local hospital.
What is cerebral angiography?
Cerebral angiography is a type of X-ray test. It uses a special dye and camera to help doctors create pictures of the blood flow in the brain. The test enables doctors to see a map of the blood vessels in the brain and neck. It also helps to show how blood flows between the different parts of the circulation.
Sometimes a cerebral angiogram (a single test is known as a cerebral angiogram) is carried out to enable doctors to give treatments directly into abnormal blood vessels.
How does cerebral angiography work?
Normally, soft, hollow structures such as blood vessels are difficult to see on X-ray images. In a cerebral angiogram a special dye called a contrast agent is injected into the arteries. The contrast agent stands out on the images created because it blocks the X-rays. This makes a picture of the blood vessels so doctors can see whether they are normal or not.
Cerebral angiography also uses a special kind of X-ray technique called fluoroscopy. A fluoroscope is an X-ray unit attached to a viewing screen. The fluoroscope uses a continuous X-ray beam to make a sequence of images. These images are fed to the screen to create a moving picture. This allows your doctor to watch as the contrast agent fills the blood vessels supplying the brain and to observe any problems or defects.
What is cerebral angiography used for?
Cerebral angiography may be used to:
- Look for blockages or narrowing of the arteries in the neck that carry blood to the brain.
- Detect an aneurysm. This is a balloon-like swelling in the wall of a blood vessel in the brain or in a blood vessel leading to the brain.
- Detect abnormal blood vessels (vascular malformations).
- Detect inflammation of the blood vessel walls (vasculitis).
- Check the pattern of blood flow to a brain tumour. This can help to show if the tumour has spread and can help guide treatment.
- Investigate symptoms that could suggest problems with the blood flow to the brain. These might include:
- Slurred speech
- Blurred vision
What happens during cerebral angiography?
The procedure can take from 30 minutes to 3 hours. You will be asked to lie flat on your back on the X-ray table. You may have an injection of a sedative into one of your veins. This helps to relax you but does not put you to sleep like a general anaesthetic. Children who have this procedure usually have a general anaesthetic to make sure they are still during the procedure. Monitoring equipment will be attached to your chest, arm and finger. You may also be given oxygen from a mask during the procedure.
The skin around the groin area is then cleaned using antiseptic, and the rest of your body is covered with sterile sheets. Your doctor will give you an injection of local anaesthetic into the groin. This will sting for a short time and then the area will become numb.
Once numb, a fine needle will be inserted into a blood vessel in the groin. Through the needle a long fine tube called a catheter will be inserted. Using X-ray images your doctor will carefully thread the catheter through your blood vessels until it reaches the vessels which supply blood to the brain. A dye is then injected through the catheter and a series of X-rays are taken to see how the dye moves through the blood vessels. Some people find that the injection of dye gives them a warm, flushed sensation or a metallic taste in their mouth. This usually passes quickly.
After the X-rays are taken, the needle and catheter are withdrawn. Pressure is applied for about 10-15 minutes on the place where the needle was inserted, to stop any bleeding. After that time, the area is checked and a tight bandage may be applied.
What should I do to prepare for cerebral angiography?
Your local hospital should give you specific advice about the preparation necessary before your procedure. This will vary from person to person.
You may be required to stay in hospital the night before the procedure. If this is not necessary, you will be given instructions on what you can eat and drink at home before coming into hospital.
If you take any blood-thinning (anticoagulant) pills you may be asked to stop taking these for a few days before the test. If you take metformin, a medication commonly used to treat diabetes, you may also be given special instructions about when to take this before the test.
What can I expect after cerebral angiography?
You may bleed from the area where the thin, flexible tube (catheter) was inserted. This can be minimised by applying pressure for a few minutes after the procedure. A bruise may develop where the catheter was inserted, and some discomfort may be felt in this region. This should not be severe and simple pain relief is usually enough. Some people will stay in hospital overnight after a cerebral angiogram. If you are allowed to go home, you should arrange for someone to collect you from hospital.
You should seek medical help if you develop any of the following problems after a cerebral angiogram:
- Chest pain.
- Difficulty breathing.
- Vision problems or slurred speech.
- Weakness in the muscles of your face or in your arms or legs.
- Severe pain in your tummy (abdomen) or back.
- Numbness, tingling, pain, swelling, loss of colour, coolness in the arm or leg where the catheter was inserted.
- A high temperature (fever).
- Increased pain, swelling, redness, pus or warmth around the area where the catheter was inserted.
Are there any side-effects or complications from cerebral angiography?
Pregnant women, if possible, should not have a cerebral angiogram, as there is a small risk that X-rays may cause an abnormality to the unborn child. Tell your doctor if you are, or think you may be, pregnant.
The dose of X-ray radiation is generally quite low. So, the risk of harm is small and it is considered a safe test.
Most people who have a cerebral angiogram cope well with the procedure. The most common side-effect is a bruise in the groin where the thin, flexible tube (catheter) was inserted. This will usually be a small bruise. However, some people can have a major bruise involving most of the upper thigh and the groin. This may take a few days or, in extreme cases, several weeks to disappear. There is only a small risk of infection because no cuts (incisions) are necessary.
Some people complain of a headache for a few hours after the examination. This may occasionally last for a few days.
Sometimes when you wake up after the examination you may find that you are unable to see clearly and some people complain of blurred vision for a few hours. Rarely, people lose the ability to speak clearly or they find that they are unable to move one or more of their limbs after the procedure. These are usually temporary complications, which pass after a few hours. However, in very rare cases, permanent loss of speech, vision or use of limbs may occur. This is due to the small risk of damage to arteries, or blood clots caused by the procedure.
Occasionally, people develop an allergic reaction to the dye used in this procedure.
Children usually have a cerebral angiogram under general anaesthetic (although some teenagers may choose to be awake during the test). Although every anaesthetic carries a risk, this is small.
Dr Rachel Hoad-Robson
Dr Mary Harding
Prof Cathy Jackson