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In angiography, x-rays are used to produce detailed images of blood vessels. It is sometimes called conventional angiography to distinguish it from computed tomography (CT) angiography and magnetic resonance angiography. During angiography, doctors can also treat disorders of blood vessels.
Angiography can provide still images or motion pictures (called cineangiography). Cineangiography can show how fast blood travels through blood vessels.
Angiography, although invasive, is relatively safe.
Before the procedure, people are usually asked to refrain from eating and drinking for 12 hours. For the procedure, people lie on an x-ray table. Because the table may be tilted, straps may be applied across the chest and legs. X-ray cameras can be positioned as needed. Electrodes are placed on the chest to monitor the heart. Blood pressure and oxygen levels in blood are also monitored.
After injecting a local anesthetic, a doctor makes a small incision, typically in the arm or groin. Then a thin, flexible tube (catheter) is inserted, usually into an artery, and is threaded through blood vessels to the area being evaluated. When the catheter is in place, a radiopaque dye (which can be seen on x-rays) is injected. The dye flows through the blood vessels and outlines them. The images appear on a video screen and are recorded. Thus, doctors can assess the structure of blood vessels and identify any abnormalities present.
Before angiography, people are often given a sedative intravenously to help them relax and remain calm, but they remain conscious during the procedure. During the procedure, people may be asked to take deep breaths, hold their breath, or cough. People should report any discomfort they feel. Angiography may take less than an hour or several hours, depending on the area of the body being evaluated and the type of the examination or procedures being done. It is usually done as an outpatient procedure.
If the catheter is inserted into an artery, the insertion site must be steadily compressed for 10 to 20 minutes after all the instruments are removed. Compression reduces bleeding and bruises. People may need to lie flat for several hours after the procedure to help prevent bleeding. Sometimes they need to stay overnight in the hospital. For the remainder of the day, they are advised to rest and to drink extra fluids to help eliminate the dye from the body.
Angiography is used to check for abnormalities in blood vessels. Abnormalities may include blockages, narrowing, abnormal tangled clumps of arteries and veins (arteriovenous malformations), inflammation (vasculitis), bulges (aneurysms) in a weakened blood vessel wall, and tears (dissection) in a blood vessel wall.
During angiography, procedures to treat the abnormalities detected can sometimes be done:
X-ray images of arteries are taken before and after a radiopaque dye is injected. Then a computer subtracts one image from the other. Images of structures other than arteries (such as bones) are thus eliminated. As a result, the arteries can be seen more clearly.
Common Types of Angiography
For some people, the procedure is uncomfortable. In a few people, allergic-type reactions to the dye occur. The injection site may bleed, become infected, or be painful. Rarely, the catheter damages a blood vessel. Serious complications, such as shock, seizures, kidney damage, and sudden stopping of the heart’s pumping (cardiac arrest), are very rare. Sometimes during cardiac catheterization, the heart skips beats or slows briefly. The risk of complications is higher in older people, although it is still low.
The dose of radiation used in angiography can vary, from about 77 to 263 times as much as that used in two plain x-rays of the chest.
Angiography is not always readily available. It must be done by highly skilled people.
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