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This booklet has been written by the Neurovascular Team at the National Hospital for Neurology and Neurosurgery. The aim of this booklet is to provide information about a diagnostic procedure called a cerebral angiogram. It is intended for use by patients (or their family or carers), who have been referred to our service for this procedure; it is not intended to replace discussion with your consultant.

If you have any questions, or would like further information about cerebral angiograms, please do not hesitate to contact a member of the team caring for you, our Neurovascular Clinical Nurse Specialists or a member of the Neuroradiology team, who will be happy to answer them for you.

A cerebral angiogram is an x-ray examination of the brain which gives highly detailed information about the brain’s blood vessels and the flow of blood through the brain. A clear fluid (contrast agent) which is opaque to x-rays is injected and allows the blood vessels to be seen on x-ray.

The information obtained can be useful in your diagnosis and can help to plan further treatment. Your doctor will explain to you in detail why they have requested a cerebral angiogram for you.

All treatments and procedures have risks and we will talk to you about the risks of having an angiogram.

Problems that may happen straight away

You may experience some stinging when the local anaesthetic is first injected into the skin at the beginning of the procedure when the Neuroradiologist inserts a catheter into your artery.

During your procedure a contrast agent will be injected into to the arteries to visualise the aneurysm for treatment. Contrast agents are safe drugs; however as with all drugs, they have the potential to cause an allergic reaction. The department is equipped to deal with reactions in the rare event of this happening. If you have known hyperthyroidism, previous kidney problems or kidney failure or are currently taking a medication called metformin, please contact Neuroradiology prior to your treatment, as we may need to provide you with further instructions before having a contrast enhanced procedure.

Problems that may happen later

The contrast agent used during a cerebral angiogram is iodine based contrast and is excreted through the kidneys; this may affect your kidney function. You will have a blood test to test your kidney function beforehand to ensure it is safe for you to have contrast. The risk of you having contrast will be weighed against the benefit of having this treatment and is decided by the team referring you. For further information on the use of iodine based contrast agents please see the information leaflet ‘Contrast Agents for X-ray, Fluoroscopy, CT and Angiography Examinations: An Information Guide’ or alternatively visit the trust website.

You may experience a headache or tiredness following the procedure. A mild painkiller, rest and drinking plenty of water will help.

Problems that are rare, but serious

Whilst serious complications remain very unlikely, there are some risks evident. Like all procedures involving the blood vessels of the brain, a cerebral angiogram carries a small risk of stroke. This can range from a minor problem which improves over time to a severe disability involving movement, balance, speech or vision or may even be a threat to life. On our current evidence, we would estimate that about one person in 100 will experience these problems. Any problem is usually apparent during or immediately after the procedure.

Haematoma, bruising or vessel damage around the puncture site may also occur. This is rarely serious but can go on for a few hours. Very occasionally, there is damage to the blood vessel requiring a further surgical operation. You will need to be monitored carefully in hospital for the first few hours to control your blood pressure and blood clotting.

Radiation Risk

The use of X-rays during the procedure presents a very small risk of hair loss, skin erythema (reddening) or very rarely the development of cancers in the future. Our state of the art imaging equipment and modern techniques ensure the radiation dose is as low as possible. In addition, your doctor will have made a judgement about your risk and benefit before agreeing to the procedure (including the risk to your health of not having the procedure).

Patients of child bearing capacity between the ages of 12 and 55 years are required by law to be asked about possible pregnancy when undergoing examinations involving x-ray.

Patients who either are, or think they may be pregnant must inform the Neuroradiology department as soon as possible. In some urgent cases the scan may still go ahead but with additional precautions in place. To reduce the risk for early and unknown pregnancies, cerebral angiograms are usually performed within the first ten days of the menstrual cycle when pregnancy is much less likely.

The Neuroradiologist performing the procedure will discuss all possible risks with you and give you the opportunity to ask questions.

The decision to have this diagnostic examination is entirely yours. To decline to have this procedure will not affect our attitude towards you or influence any other aspect of your care. It may mean, however, that your doctor cannot be as certain or specific about any future treatment or procedures.

Your Consultant or Clinical Nurse Specialist will discuss alternative investigations with you. In some circumstances it may be possible to have a CT or MRI scan.

On the day of your angiogram you will be asked to arrive at 8am to the surgical reception unit (SRU) or to the ward specified by the admission officer in contact with you. Arriving late may mean your angiogram is cancelled. Your procedure may take place at any time during the day, due to emergency cases, but we will endeavour to keep you informed and perform your procedure as early in the day as possible. You may wish to bring a book or something to keep you entertained whilst you wait.

On the day you may eat a light breakfast, to be finished by 7am. You may drink water freely, but no other type of dinks before the procedure. You should continue to take any prescribed medication as this will not affect the angiogram.

However, if you are taking insulin or metformin to control diabetes or any medication to prevent blood clots such as warfarin or clopidogrel please contact the Neurovascular Nurse Specialist on 020 3448 3523. You may need to be admitted overnight for the angiogram procedure.

Angiograms are performed by specialist doctors called Neuroradiologists. A Neuroradiologist will see you on the ward to explain the angiogram and any associated risks. Please feel free to ask any questions at this time. The angiogram will be carried out under a local anaesthetic.

On the ward you will be given a hospital gown to change into. We will ask you to remove your underwear, jewellery and hair clips prior to leaving the ward.

You may also wish to bring a change of clothes and nightwear as on the rare occasion it may be necessary to stay overnight.

We want to involve you in all the decisions about your care and treatment. If you decide to go ahead with treatment, by law we must ask for your consent and will ask you to sign a consent form. This confirms that you agree to have the procedure and understand what it involves. Staff will explain all the risks, benefits and alternatives before they ask you to sign a consent form. If you are unsure about any aspect of your proposed treatment, please don’t hesitate to speak with a senior member of staff again.

The procedure is performed by a Neuroradiologist in the angiography suite (operating theatre) located in the radiology department and will take approximately one hour.

A dedicated team, of Neuroradiologists(the doctor who will perform the procedure), radiographers (the staff who operate the x-ray machinery) and nurses will be with you in the room during the procedure.

You will be moved onto the x-ray table with your head positioned in a special headrest. The nurse will expose the area at the top of the thigh (groin) or the forearm, depending where the Neuroradiologist will access your blood vessels from. The area is cleaned with sterilising solution and you will be covered with sterile sheets.

Local anaesthetic is injected into the groin or arm. This may sting a little at first but will reduce any further discomfort during the procedure. A very thin plastic tube called a catheter is then threaded into the blood vessel in your groin (femoral artery) or your arm (radial artery). The catheter passes through the main artery in the body called the aorta and finally into the chosen artery supplying the brain. You will not feel this tube moving inside you.

A series of X-rays of the blood vessels are taken whilst injecting contrast agent through the catheter. It is important that you stay very still during the angiogram in order to achieve the best possible images of your blood vessels. We may take more than one series of images/ images of one blood vessel, dependent on why you have been referred for an angiogram.

You should not feel any pain apart from a small scratch from the local anaesthetic needle.

During the injection of the contrast agent you may experience a warm feeling, see stars and lights, hearing bussing noises and/or a strange taste. All of these are normal and only last a few seconds after the injection. Please inform the Neuroradiologist if any of these are particularly unpleasant.

When all the X-rays have been taken the catheter will be removed from your groin or arm. The Neuroradiologist will press firmly on this area in your groin for about ten minutes to prevent bleeding. If the radial artery has been accessed then this site is sealed with a balloon compression wrist band. At this stage of the procedure, it is a good opportunity to ask any questions.

You will be taken back to the ward where you will have a minimum of four hours strict bed rest; you must remain lying in bed keeping your legs straight. This is to protect the groin site. You may have your head raised up to a thirty degree angle for comfort. You may eat and drinks as normal after your angiogram.

The Nursing staff will carry out regular observations; this includes checking the puncture site in your groin or arm for any signs of bleeding, excessive bruising or swelling. It is normal to have a little bruising around the groin or arm area and the area may be uncomfortable. Most people have little or no after effects.

You must stay in the hospital for a minimum of six hours following return to the ward. In some cases you may need to stay in the hospital overnight following the angiogram and if there are no problems you will be able to go home the following morning.

If you have any concerns, you should discuss them with the staff on the ward, or ask to see one of the Doctors.

The Neuroradiologist will review the images taken during your angiogram and write a report, this will be available to your Consultant on completion. You will be contacted by your Consultant’s team by letter or telephone with your results and plan, four to six weeks after your procedure.

Discharge requirements

  • A responsible adult must escort you home by car or taxi.
  • A responsible adult must stay with you until the following morning.
  • You must have immediate access to a telephone.

Discharge the day after the angiogram

  • You will be assessed first thing in the morning and discharged homed if all is well. You may travel by public transport.

Guidance for the first two days following angiography

  • Minimise physical activity until the next morning. After this you may resume normal activity.
  • For 48 hours after the angiogram avoid tasks that put additional pressure on your groin or arm. This includes sexual activity, driving, excessive stair climbing, long walks and lifting heavy objects.

Care of the puncture site and post procedure complications

  • Check the puncture site for swelling or hardness. A small lump and bruising at the puncture site are common and normal.
  • If the hared lump grows in size or you notice numbness, coolness or pain down your leg (groin/femoral puncture) or arm (radial puncture) you must go to your local Accident & Emergency department for advice.
  • If the puncture site bleeds heavily (this is very rare) please apply firm pressure and telephone 999 for an ambulance.
  • Keep the puncture site clean and dry until it is healed.
  • If you feel severely unwell in any way call an ambulance immediately.

If you have any concerns and you need to contact NHNN after your discharge, please call the hospital switchboard on 020 3456 7890 between the hours of 9am to 5pm Monday to Friday; ask for the neuro-angiography suite on extension 83444. After 5pm and weekends, ask to be connected to the on-call Neuroradiology registrar.

The Brain & Spine Foundation

Tel: 020 7793 5900

Helpline: 0808 808 1000

Fax: 020 7793 5939


UCLH cannot accept responsibility for information provided by other organisations.

Lysholm Department of Neuroradiology

National Hospital of Neurology and Neurosurgery

Queen Square



Direct line: 020 344 83444

Switchboard: 0845 155 5000/ 020 3456 7890

Extension: 83444/ 83446

Fax: 020 344 84723




Neurovascular Clinical Nurse Specialists

The National Hospital for Neurology and Neurosurgery

Queen Square



Direct line: 020 344 83523

Switchboard: 0845 155 5000 / 020 3456 7890

Extension: 83523



The Lysholm Department of Neuroradiology reception is located in Chandler wing, on the lower ground floor of the National Hospital for Neurology & Neurosurgery, Queen Square.

Please turn left when you exit the Chandler wing lifts on the lower ground floor to find our main departmental reception.

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Page last updated: 01 May 2024

Review due: 30 November 2024