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.
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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.
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Is angiography dangerous?

• A small minority of patients are 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.

Angiography or arteriography is a medical imaging technique in which an X-ray picture is taken to visualize the inner opening of blood filled structures, including arteries, veins and the heart chambers. Its name comes from the Greek words angeion, "vessel", and graphien, "to write or record". The X-ray film or image of the blood vessels is called an angiograph, or more commonly, an angiogram.

The Portuguese physician and neurologist Egas Moniz, Nobel Prize winner in 1949, developed in 1927 the technique of contrasted x-ray cerebral Angiography to diagnose several kinds of nervous diseases, such as tumors and arteriovenous malformations. He is usually recognised as one of the pioneers in this field. With the introduction of the Seldinger technique in 1953, the procedure became markedly safer as no sharp introductory devices needed to remain inside the vascular lumen.

Angiograms require the insertion of a catheter into a peripheral artery, e.g. the femoral artery.

As blood has the same radiodensity as the surrounding tissues, a radiocontrast agent (which absorbs X-rays) is added to the blood to make Angiography visualization possible. The angiographic X-Ray image shows shadows of the openings within the cardiovascular structures carrying blood (actually the radiocontrast agent within). The blood vessels or heart chambers themselves remain largely to totally invisible on the X-Ray image.

The X-ray images may be taken as either still images, displayed on a fluoroscope or film, useful for mapping an area. Alternatively, they may be motion images, usually taken at 30 frames per second, which also show the speed of blood (actually the speed of radiocontrast within the blood) traveling within the blood vessel.

The most common angiogram performed is to visualize the blood in the coronary arteries. A long, thin, flexible tube called a catheter is used so as to administer the radiocontrast agent at the desired area to be visualized. The catheter is threaded into an artery in the groin or forearm, and the tip is advanced through the arterial system into one of the two major coronary arteries. X-ray images of the transient radiocontrast distribution within the blood flowing within the coronary arteries allows visualization of the size of the artery openings. Presence or absence of atherosclerosis or atheroma within the walls of the arteries cannot be clearly determined. See coronary catheterization for more detail.

Angiography is also commonly performed to identify vessel narrowing in patients with retinal vascular disorders, such as diabetic retinopathy and macular degeneration.

Interventional Radiologists are Vascular Experts:
Angiography is an X-ray exam of the arteries and veins to diagnose blockages and other blood vessel problems.

Interventional radiologists use imaging to diagnose, understand and visualize the full scope of the pathology and to map out the procedure tailored to the individual patient. An interventional radiologist performs this X-ray procedure, which is also called an angiogram. During the angiogram, the doctor inserts a thin tube (catheter) into the artery through a small nick in the skin about the size of the tip of a pencil. A substance called a contrast agent (X-ray dye) is injected to make the blood vessels visible on the X-ray.

One of the most common reasons for angiograms is to see if there is a blockage or narrowing in a blood vessel that may interfere with the normal flow of blood through the body. In many cases, the interventional radiologist can treat a blocked blood vessel without surgery at the same time the angiogram is performed. Interventional radiologists treat blockages with techniques called angioplasty and thrombolysis.

• Additional Reasons for Performing Angiography or Angiogram
   
• aneurysms -- an area of a blood vessel that bulges or balloons out
   
• cerebral vascular disease, such as stroke or bleeding in the brain
  blood vessel malformations.