Angiography of Peripheral Blood Vessels
In angiography of the peripheral arteries (those of the arms, legs, and trunk—except those supplying the heart) a thin catheter (a small, flexible, hollow plastic tube) is inserted into an artery in the neck, arm, or groin/upper thigh through a puncture made with a needle. A local anesthetic is given to numb the insertion site. The catheter is then threaded through the major blood vessels and into the blood vessel that is being tested. The procedure is done in the hospital and takes 40 to 60 minutes. Coronary angiography is similar, except the catheter is threaded into the arteries supplying the heart.
Angiography may be done to detect narrowing or blockage of an artery (peripheral arterial disease), a bulge (aneurysm) in an artery, or an abnormal channel between an artery and a vein (arteriovenous fistula). Over the past several decades, advances in the use of computed tomography (CT) and magnetic resonance imaging (MRI) for noninvasive angiography has made the use of these invasive angiography techniques much less common.
Angiography of the aorta (aortography) can be used to detect abnormalities (such as an aneurysm or a dissection) in the aorta. It can also be used to detect leakage of the valve between the left ventricle and the aorta (aortic regurgitation).
Digital subtraction angiography may be done before selective angiography to detect and visualize problems such as narrowing or blockage of an artery. However, this type of angiography is seldom adequate to determine whether surgery (with or without angioplasty) is needed. Digital subtraction angiography is not used for coronary arteries because it is unnecessary. Clear images of these arteries can be obtained when a radiopaque dye is injected directly into a coronary artery.
In digital subtraction angiography, images of arteries are obtained before and after a radiopaque dye is injected, and a computer subtracts one image from the other. Images of tissues other than the arteries (such as bones) are thus eliminated. As a result, the arteries can be seen more clearly, much less dye is required, and the procedure may be safer than standard angiography.