Angiography - ț̢
Radiography of blood vessels after injection of a contrast medium.
Synonyms : Angiographies, Arteriographies
Angiography, Digital Subtraction - ț̢
A method of delineating blood vessels by subtracting a tissue background image from an image of tissue plus intravascular contrast material that attenuates the X-ray photons. The background image is determined from a digitized image taken a few moments before injection of the contrast material. The resulting angiogram is a high-contrast image of the vessel. This subtraction technique allows extraction of a high-intensity signal from the superimposed background information. The image is thus the result of the differential absorption of X-rays by different tissues.