Angiography or arteriography is a medical imaging technique.
It is used to visualize the lumen, of blood vessels and organs of the body.
It evaluates arteries, veins, and the heart chambers.
It is done by injecting a radio-opaque contrast agent into the blood vessel and imaging using X-ray based techniques such as fluoroscopy.
The term angiography has been applied to radionuclide angiography and vascular imaging techniques such as CO2 angiography, CT angiography and MR angiography.
Access to the blood vessels is gained most commonly through the femoral artery, to look at the left side of the heart and at the arterial system; or the jugular or femoral vein, to look at the right side of the heart and at the venous system.
Angiography is also commonly performed to identify vessels narrowing in patients with leg claudication or cramps, caused by reduced blood flow down the legs and to the feet.
It is used in patients with renal stenosis and can be used in the head to find and repair stroke.
Stenoses may be treated by the use of balloon angioplasty, stenting, or atherectomy.
Post mortem CT angiography for medicolegal cases.
Major complications in cerebral angiography such as in digital subtraction angiography or contrast MRI are rare but include stroke, an allergic reaction to the anaesthetic other medication or the contrast medium, blockage or damage to one of the access veins in the leg, or thrombosis and embolism formation.
Bleeding at the site where the contrast is injected are minor complications.
The contrast medium that is injected usually produces a sensation of warmth lasting only a few seconds.
With new contrast agents the risk of a severe allergic reaction is less than one in 80,000 examinations.
Damage to blood vessels can occur at the site of puncture/injection, and along the vessel as the catheter is passed.
With digital subtraction angiography the risks are reduced because the catheter does not need to be passed as far into the blood vessels.
X-ray imaging may be still, displayed on an image intensifier or film, or motion images.
For all structures except the heart, the images are usually taken using a digital subtraction angiography or DSA.
Digital subtraction angiography(DSA)
images are usually taken at 2–3 frames per second, which allows the interventional radiologist to evaluate the flow of the blood through a vessel or vessels.
The heart images uses 15–30 frames per second, not using a subtraction technique.
DSA requires motionless, and therefore cannot be used on the heart.
Angiographic techniques enable to see stenosis, blockages or narrowings, inside the vessel which may be inhibiting the flow of blood and causing pain.
((Coronary angiography)) can visualize coronary artery stenosis, or narrowing of the blood vessel.
To detect coronary artery disease, a CT scan is more satisfactory than an MRI scan.
Sensitivity and specificity between CT and MRI are 97.2 percent and 87.4 percent and 87.1 percent and 70.3 percent, respectively diagnosing CAD.
Therefore, CT (mainly multislice CT) is more accepted, more widely available, more favored by patients, and more economic. Moreover, CT requires shorter breath-hold time than MRI.
Fluorescein angiography is a medical procedure in which a fluorescent dye is injected into the bloodstream.
Fluorescein angiography can accentuate the blood vessels in the retina.
Optical coherence tomography (OCT uses near-infrared light to image the retina to view the micro-structure behind the retinal surface, to assess its vascular health.
Neuro-vascular digital subtraction angiography is used to visualise the arterial and venous supply to the brain.
Interventions such as coil-embolization of aneurysms and AVM gluing can also be performed via angiography.
Angiography is commonly performed to identify vessels narrowing in patients with leg claudication caused by reduced blood flow down the legs and to the feet.
Angiography is commonly performed to identify renal stenosis, to find and repair strokes related to stenosis: treated by the use of balloon angioplasty, stenting, or atherectomy.
Major complications in cerebral angiography are also rare but include stroke, an allergic reaction to the anaesthetic other medication or the contrast medium, blockage or damage to one of the access veins in the leg, or thrombosis and embolism formation.
Minor bleeding or bruising at the site where the contrast is injected may occur.
Modern contrast agents have an associated risk of a severe reaction of less than one in 80,000 examinations.
Damage to blood vessels can occur at the site of puncture/injection.
Damage to blood vessels can also occur
anywhere along the vessel during passage of the catheter.
With digital subtraction angiography the risks are reduced because the catheter does not need to be passed as far into the blood vessels.