Merck Manual

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Mehmet Kocak

, MD, Rush University Medical Center

Last full review/revision Apr 2021| Content last modified Apr 2021
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IV contrast is injected through a catheter inserted into a blood vessel that connects with the vessel to be imaged. A local anesthetic or a sedative may be used. If the catheter is inserted into an artery, the insertion site must be steadily compressed for 10 to 20 minutes after all instruments are removed to reduce the risk of bleeding at the puncture site. Patients may also need to lie flat for several hours or be hospitalized to reduce this risk. Alternatively, a patch can be inserted to seal the puncture site.

Angiography, although invasive, is relatively safe.

Uses of Angiography

CTA and MRA are often done instead of conventional angiography. However, conventional angiography is the traditional gold standard for evaluating vascular lesions (eg, stenosis, obstruction, arteriovenous or other vascular malformations, aneurysms, dissections, vasculitis).

Common uses of conventional angiography include the following:

Conventional pulmonary angiography used to be the gold standard for diagnosis of pulmonary embolism; now, it has largely been replaced by CT pulmonary angiography (CTPA), which is less invasive.

Conventional angiography is usually done before therapeutic angiographic procedures such as angioplasty, vascular stenting, and embolization of tumors and vascular malformations.

Variations of Angiography

Digital subtraction angiography

Images of blood vessels are taken before and after contrast injection; then a computer subtracts the pre-contrast image from the post-contrast image. Images of extraneous structures are thus eliminated, isolating images of the blood vessel lumens opacified by contrast.

Disadvantages of Angiography

The injection site may bleed if the injected blood vessel ruptures; a painful hematoma can form. Rarely, the site becomes infected; it becomes red and swollen and exudes a purulent discharge within a few days after the injection.

Rarely, an artery is injured by the catheter, or an atherosclerotic plaque dislodges, causing an embolism distally. Very rarely, shock, seizures, renal failure, and cardiac arrest occur.

Risk of complications is higher in older patients, although it is still low.

The radiation dose used in angiography can vary and be significant (eg, coronary angiography is associated with an effective radiation dose of 4.6 to 15.8 mSv).

Angiography must be done by highly skilled physicians, usually specially trained interventional radiologists or cardiologists.

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