Angiography is a test that uses an injection of a liquid dye to make the arteries easily visible on X-rays.
When is angiography used?

An angiogram was once commonly used to check the condition of blood vessels. Nowadays, non-invasive tests provide the same information with less discomfort and risk to the patient. These include: Doppler, digital subtraction angiography (from venous dye injection), ultrasound, CT scans and MRI scans.
• Angiography may be used if the doctor is considering surgery, because it shows a clear picture of the blood vessels.
• Angiography may reveal aneurysms (a bulge on an artery caused by a blood vessel wall becoming weaker).
• An angiogram can also be used to give a good view of the carotid artery and its branches in the neck and head. This is generally done to investigate a bleed in the brain (cerebral bleed) or identify the blood supply to a tumour. The angiogram can be used to show if an operation is necessary or possible.
• Angiography is used to look at the coronary arteries that send blood to the heart. The test is used to show if the arteries of the heart have narrowed.
• Angiography is used to look at the arteries in the legs and kidneys, as well as the aorta (the body's largest artery).
• Angiography is used to look at the liver to localise abnormalities, including tumours. This can be particularly useful when planning surgery.
How is angiography done?

Before taking an X-ray, a liquid dye is injected into the blood vessels. When the test is on the arteries of the heart, the carotid artery, or the major arteries coming from the aorta, the catheter is inserted into the groin, or occasionally the arm.
• Before a catheter can be inserted into an artery, the surrounding area has to be numbed with a local anaesthetic.
• A short, thin wire with a rounded tip is then carefully inserted into the artery using a needle. It is guided with the help of fluoroscopy (X-ray images) to the spot where the dye is needed.
• The needle is then removed and a vascular sheath inserted around the wire. A catheter may then be inserted along the guide wire.
• When the catheter is in the correct position, the wire is pulled out and dye is inserted through the catheter. The patient may experience a feeling of warmth in the area, but this will disappear after a few seconds.
• Now the blood vessels can be checked on a screen, or on a series of rapidly recorded X-rays.
Is angiography dangerous?
• A small minority of patients is allergic to the liquid dye, mainly due to the iodine content of the dye. Anyone who has previously experienced such reactions should mention this to the doctor.
• There is a small risk of the catheter damaging the blood vessels that it was inserted through.
• Cerebral angiography carries a small but significant risk of a serious adverse outcome.
• Pregnant women should enquire about the risks of the fluoroscopy (X-ray screening) harming their baby.
• Patients suffering from severe liver, heart or kidney diseases may be at greater risk, and should seek advice from the specialist.
• The risk of X-rays being harmful is very small. Modern X-ray machines are designed to take high quality pictures using the minimum radiation dose.