An angiography is a type of X-ray used to examine blood vessels. The images created during an angiography are called angiograms. Blood vessels don't show up clearly on ordinary X-rays, so a special dye is injected into the area being examined. The dye highlights the blood vessels as it moves through them, and it appears white on the angiogram. The medical name for this type of angiography is a catheter angiogram.Digital subtraction angiography (DSA) is a procedure combining enhancement of vascular contrast, real time image processing, and facilities for intensive postprocessing and analysis of images by means of digital electronics and video display. It is based on experiences from subtraction angiography which is already well-known in neuroradiographic vascular imaging. However, only digital electronic facilities are suited to modify the procedure to high enhancement levels and to supply the result in such a short time that it is readily displayed during the examination close to the patient as if it were subtraction angio-fluoroscopy.
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