Angiography and angiograms
Blood vessels can be examined by using a special medical test known as angiography, and the X-ray images that it takes are known as angiograms. There are a number of reasons for arranging angiography, and several ways to produce an angiogram.
If the blood vessels cannot deliver an adequate supply of blood, the result can be heart attack, stroke, gangrene or organ failure, so being able to detect a problem in the blood vessels can be vitally important, and one way to determine how healthy they are is to take an image of them.
How does an angiography work?
Unlike bones, blood vessels are not clearly defined on a normal X-ray. However, a special dye can be injected into the area being examined to highlight the blood vessels. An X-ray is taken once the dye has moved through the vessels and the dye appears white on the angiogram, making the vessels more prominent.
Angiograms can also be taken – albeit less often – by using magnetic resonance imaging (MRI), where a powerful magnet and radio waves are used to gather information about the vessels that is then fed to a computer to generate images, or computerised tomography (CT) scanning techniques that combine X-rays and computer technology. For example, computerised tomography pulmonary angiography (CTPA) is usually a safer option when the lungs are involved.
Angiography is used to investigate blood vessels in different parts of the body, and it may be referred to by the area of the body where it is performed:
- Cerebral angiography – the brain
- Coronary angiography – the heart (the most common area)
- Pulmonary angiography – the lungs
- Renal angiography – the kidneys
- Extremity angiography – the arms or legs
What conditions can be detected in an angiogram?
Blood vessels can be affected by several conditions, and an angiogram can help to make a diagnosis. These include:
- Aneursym, where part of the wall of a blood vessel is weak and therefore bulges
- Atherosclerosis, where fatty deposits such as cholesterol can clog up and cause narrowing of blood vessels
- Coronary heart disease, in which the artery that supplies blood to the heart is narrow and therefore the flow of blood to the heart restricted.
Do angiograms have other uses?
Not only can angiograms help in diagnosing a condition, but they can also help in determining the extent of a problem, such as how narrowed or blocked up blood vessels have become in atherosclerosis. It can help determine the amount of medication needed or the need for surgery. Specialists can use the procedure to help determine the most appropriate treatment for angina and heart attacks or to plan surgery that involves the blood vessels, such as a coronary artery bypass graft, or aortic valve replacement. Sometimes an angiogram is taken to find the site of local bleeding, to look for blood clots or to investigate internal organs that may have been injured.