angiography

Radiography of vessels after the injection of a radiopaque contrast material; usually requires percutaneous insertion of a radiopaque catheter and positioning under fluoroscopic control. SEE ALSO: arteriography, venography. [angio- + G. grapho, to write]

- biplane a. synchronous angiocardiography in two planes at right angles to each other or in two orthogonal planes.

- cerebral a. radiographic visualization of the blood vessel s supplying the brain, including their extracranial portions; the injection of contrast medium may be made percutaneously, by open exposure and puncture of the carotid artery or by catheterization after introduction of the catheter at a distant site. SYN: cerebral arteriography.

- coronary a. imaging of the circulation of the myocardium by injection of contrast medium, usually by selective catheterization of each coronary artery, formerly by nonselective injection at the root of the aorta.

- digital subtraction a. (DSA) computer-assisted radiographic a. permitting visualization of vascular structures without superimposed bone and soft tissue densities; subtraction of images made before and after contrast injection removes structures not enhanced by the contrast medium. Other image processing can be performed. Contrast material may be injected intravenously or in a lower-than-usual amount intraarterially.

- fluorescein a. photographic visualization of the passage of fluorescein through intraocular vessels after intravenous injection.

- indocyanine green a. a test for studying choroidal vasculature by which indocyanine green dye, which absorbs infrared light at 805 nm and emits at 835 nm, is injected intravenously and photographed as it flows through the retinal and choroidal vessels.

- interventional a. SYN: angioplasty.

- magnetic resonance a. SYN: MR a..

- magnification a. enhanced imaging of small blood vessel s using an increased distance from subject to film, as in magnification radiography.

- MR a. (MRA) imaging of blood vessel s using special magnetic resonance (MR) sequences that enhance the signal of flowing blood and suppress that from other tissues. SYN: magnetic resonance a..

- radionuclide a. scintillation camera imaging of tissue perfusion by intravascular injection of a radioactive pharmaceutical. SEE ALSO: radionuclide angiocardiography. SYN: scintigraphic a..

- scintigraphic a. SYN: radionuclide a..

- selective a. a. in which visualization is improved by concentrating the contrast medium in the region to be studied by injection through a catheter positioned in a regional artery, e.g., coronary a..

- therapeutic a. use of angiographic catheters that have been modified to reduce or increase regional blood flow, or to deliver medicinal agents; interventional therapeutic a.. See angioplasty, balloon catheter, interventional a..

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an·gi·og·ra·phy -fē n, pl -phies the radiographic visualization of the blood vessels after injection of a radiopaque substance

an·gio·graph·ic .an-jē-ə-'graf-ik adj

an·gio·graph·i·cal·ly -i-k(ə-)lē adv

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n.

imaging of blood vessels (see also coronary angiography, lymphangiography). Fluoroscopic angiography is performed by injection of contrast medium during X-ray fluoroscopy. Positive (radiopaque) contrast medium containing iodine or, more recently, negative (radiolucent) gas (carbon dioxide) may be used. digital subtraction increases the visibility of the vessels. Magnetic resonance angiography (MRA) can be performed either by injection of a magnetic resonance contrast agent (see contrast medium), which gives an increased signal from the blood, or by relying on the movement of blood to give a lack of signal in the plane being examined. 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 enhance the density of the blood. This can then be clearly seen on either two- or three-dimensional images, with other surrounding tissues hidden by the computer. 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, using a newer dye, gives much better visualization of the choroidal circulation. It is particularly useful for visualization and treatment of choroidal neovascular membranes (see neovascularization).

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an·gi·og·ra·phy (an″je-ogґrə-fe) [angio- + -graphy] the radiographic visualization of blood vessels following introduction of contrast material; used as a diagnostic aid in such conditions as stroke syndrome and myocardial infarction. See also arteriography and phlebography. Called also vasography.