An imaging procedure that enables blood vessels to be seen clearly on X-ray film following the injection of a contrast medium (a substance
that is opaque to X-rays). Angiography is used to detect conditions that alter the appearance of blood vessels, such as aneurysm, and narrowing or blockage of blood vessels by atherosclerosis, or by a thrombus or embolus. It is also used to detect changes in the pattern of blood vessels that supply organs injured or affected by a tumour.
Carotid angiography (of the arteries in the neck) may be used to investigate transient ischaemic attacks. Cerebral angiography can be used to detect an aneurysm in the brain or pinpoint the position of a brain tumour. Coronary angiography, often combined with cardiac catheterization, can identify the sites of narrowing or blockage in coronary artery disease. Digital subtraction angiography uses computer techniques to process images and remove unwanted background information.
Angiographic techniques have been adapted to allow certain treatments that, in some cases, eliminate the need for surgery (see angioplasty, balloon; embolization). (See also aortography.)
Radiography of blood vessels made visible by injecting into them a radio-opaque substance. In the case of arteries this is known as arteriography; the corresponding term for veins being venography or phlebography. This procedure demonstrates whether there is any narrowing or ballooning of the lumen of the vessel, changes usually caused by disease or injury.
n. imaging of blood vessels (see also coronary angiography; lymphangiography). In the older form of angiography X-ray imaging was carried out after injection of *radiopaque contrast medium and *digital subtraction applied to enhance visualization. The use of X-rays has now been largely replaced by methods using MRI or CT scanners. Magnetic resonance angiography (MRA) can be performed with (contrast-enhanced) or without (noncontrast) injection of a magnetic resonance contrast agent (see contrast medium). Contrast-enhanced MRA will show the vessels better. These images can be reconstructed in two or three dimensions. Computerized tomographic angiography (CTA) uses a radiographic contrast agent, usually injected into a vein, to increase the visibility of the blood vessels. Fluorescein angiography is a common method of investigation in ophthalmology. *Fluorescein sodium is injected into a vein in the arm, from which it circulates throughout the body. Light of an appropriate wavelength is shone into the eye, causing the dye in the retinal blood vessels to fluoresce. This allows the circulation through the retinal blood vessels to be observed and photographed. Indocyanine green (ICG) angiography uses indocyanine green dye, which fluoresces in infrared light. It is valuable in assessing circulation in the deeper layers of the *fundus.
an X-ray technique for examination of the coronary arteries, often taken to also include examination of the chambers of the heart. A catheter is introduced via the radial artery at the wrist or the femoral artery at the groin and manipulated into the heart under X-ray control. *Contrast medium is then injected to outline the ventricles and coronary arteries. Digital video images are recorded during contrast-medium injection. Coronary angiography is used to diagnose cardiac disease, specifically narrowing or blockage in the coronary arteries, and plan treatment by surgery or radiological interventional techniques (see coronary artery bypass graft; percutaneous coronary intervention). It has now largely been replaced by CT coronary angiography.... coronary angiography
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