Angiography is the imaging of blood vessels using water-soluble ionic or nonionic X ray contrast media injected into the blood stream of arteries (arteriography) or veins (venography). For lymph vessels, oily contrast media are used.
Angiography serves to investigate normal and pathological states of the vessel system particularly luminal narrowing and obstruction or aneurysmal widening. Furthermore tumour conditions, arteriovenous malformations (AVM) and arteriovenous fistulae (AVF) or sources of bleeding are investigated with angiography. Complications are low but differ somewhat according to vessel access. In the arterial system, the lowest complication rates are reported for the femoral access with 1.73%, 2.98% for translumbar arteriography, and highest for the transaxillary approach with 3.23%. These complications will result mainly from local problems such as haematoma, pseudoaneurysms and arteriovenous fistulae, etc., or from guide wire and catheter manipulation. The second group of complications comprises side effects of the contrast material on renal function and systemic effects or allergic reactions.
Today, images are taken mainly with digital subtraction techniques (digital subtraction angiography DSA), however, single shot or fast series may also be taken with rapid film changers, in cine mode (cine angiography for coronary arteries) or as digital video recordings directly from the image intensifier screen.
Injection of contrast material into arteries and veins is performed either directly via a needle puncture or using a percutaneously inserted angiographic catheter most commonly made from polyethylene, polyurethane or nylon. Contrast injection is done by hand (mainly in direct needle puncture or in small caliber arteries) or with a power injector.
A specific terminology is derived from 1) the organ to be imaged, e.g. coronary, cerebral, renal, hepatic angiography, 2) the vessel area, e.g. aortography, peripheral angiography, cavography, 3) from the chosen method of access to the desired vessel or organ area, e.g. direct arterio/venography or catheter arterio/venography, and 4) the choice of vessel access, e.g. transfemoral, transaxillary, brachial, translumbar and direct or indirect splenoportography. All these various terms may be used in a combination such as super-selective transfemoral hepatic arteriography, which means the catheter has been advanced into at least a second degree branch of the hepatic artery from a femoral approach.
Angiographic studies are routinely performed under local anaesthesia. After infiltration of the skin and the tissue around the artery or vein to be punctured, a small skin incision is made, and the artery is punctured with an angiographic needle. For percutaneous catheter insertion, the Seldinger technique is used.
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