Angiographers operate diagnostic imaging equipment to produce contrast-enhanced radiographs of blood vessels to aid physicians in the diagnosis and treatment of disease. Angiography is an x-ray examination of the blood vessels after they have been filled with a contrast agent (a type of fluid that makes the vessels visible on an x-ray image).
Angiography is performed when your physician suspects blockages of arteries or veins that may interfere with the normal flow of blood through the body. It also is used to detect aneurysms, to image malformations in a blood vessel, to detect stroke or bleeding in the brain, and to find irregularities that can affect the heart or other organs. It is used to diagnose angina, which causes severe pain in the chest, brought on by physical or emotional distress. In this case, not enough blood is being received by the cardiac muscle due to narrowing of the arteries caused by fatty deposits.
Angiographers position the patient on the examination table and immobilise the head and shoulders. They operate fluoroscopes to enable the physician to view and guide a wire or catheter to the required blood vessel. The catheter is a flexible, hollow tube about the size of a strand of spaghetti. It usually is inserted into an artery in the groin, although in some cases the arm or another site may be selected.
Angiographers then inject the contrast agent through the catheter and control the flow rate. They monitor the video display of the area being examined and adjust the density and contrast for maximum exposure. They then start the filming sequence and deliver the film to be developed. These x-rays are then reviewed for accuracy and quality of exposure.
Angiography also can be performed using magnetic resonance instead of x-rays to produce images of the blood vessels, known as magnetic resonance angiography (MRA), or magnetic resonance venography (MRV).
In addition to producing images of the blood vessels, angiography can be used to help repair the vessels. During a procedure known as balloon angioplasty, angiography is used to guide a balloon through the catheter to a blocked or narrowed area of an artery. The balloon is inflated, compressing plaque against the walls of the artery and widening it. After deflating the balloon, the catheter is removed. In cases where the artery cannot be stretched by balloon angioplasty, a surgical stent can be inserted into the vessel to help keep it open. Stents are small, cylindrical supports made of metal.