Digital subtraction angiography

Digital subtraction angiography
Digital subtraction angiography
Intervention

Example of iodine-based contrast in cerebral angiography
MeSH D015901

Digital subtraction angiography (DSA) is a type of fluoroscopy technique used in interventional radiology to clearly visualize blood vessels in a bony or dense soft tissue environment. Images are produced using contrast medium by subtracting a 'pre-contrast image' or the mask from later images, once the contrast medium has been introduced into a structure. Hence the term 'digital subtraction angiography'.

Contents

Applications

DSA is primarily used to image blood vessels. It is useful in the diagnosis and treatment of:

DSA and Fluoroscopy

In traditional angiography images are acquired by exposing an area of interest with time-controlled x-rays while injecting contrast medium into the blood vessels. The image obtained would also include all overlying structure besides the blood vessels in this area. This is useful for determining anatomical position and variations but unhelpful for visualising blood vessels accurately.

In order to remove these distracting structures to see the vessels better, first a mask image is acquired. The mask image is simply an image of the same area before the contrast is administered. The radiological equipment used to capture this is usually an image intensifier, which will then keep producing images of the same area at a set rate (1 - 6 frames per second), taking all subsequent images away from the original 'mask' image. The radiologist controls how much contrast media is injected and for how long. Smaller structures require less contrast to fill the vessel than others. Images produced appear with a very pale grey background, which produces a high contrast to the blood vessels, which appear a very dark grey.

The images are all produced in real time by the computer, as the contrast is injected into the blood vessels.

The future

DSA is being used less and less routinely in imaging departments. It is being taken over by computed tomography angiography (CTA), which can produce 3D images through a test which is less invasive and stressful for the patient.[citation needed]

See also

External links

v · d · eHealth science – Medicine · Surgery · Vascular surgery and other vascular procedures (ICD-9-CM V3 38-39, ICD-10-PCS 03-6)
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and occlusion
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Medical imaging

Angiography (Digital subtraction angiography, Cerebral angiography, Aortography, Fluorescein angiography, Radionuclide angiography, Magnetic resonance angiography)

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Intravascular ultrasound · Carotid ultrasonography
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Look at other dictionaries:

  • Intravenous digital subtraction angiography — (IV DSA) is a form of angiography which was first developed in the late 1970s. IV DSA uses a computer technique which compares an x ray image of a region of the body before and after radiopaque iodine based dye has been injected intravenously… …   Wikipedia

  • digital subtraction angiography — a computerized x ray technique in which arteries are visualized following injection of dye into a vein. Abbr.: DSA * * * …   Universalium

  • digital subtraction angiography — an angiographic technique that produces images by subtracting background structures and enhancing the contrast of those areas that change in density between a preliminary “mask” image and subsequent images …   Medical dictionary

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  • digital subtraction aortography — digital subtraction angiography of the aorta. Digital subtraction aortography of a normal aortic arch, in a left anterior oblique (Lao) projection. A Ao, ascending aorta; D Ao, descending aorta; BC,brachiocephalic artery; LCC, left common carotid …   Medical dictionary

  • digital subtraction radiography — use of digital subtraction to monitor the flow of contrast medium on radiographs over time; the most common application is digital subtraction angiography …   Medical dictionary

  • digital subtraction — a sophisticated radiological technique in which digitization allows X ray examination, most commonly of blood vessels (see angiography), to be performed using smaller volumes of contrast material. A digitized image is taken before the contrast… …   Medical dictionary

  • intra-arterial digital subtraction angiography — a type of arteriography that uses electronic circuitry to subtract the background of bone and soft tissue to provide a useful image of the arteries injected with contrast medium …   Medical dictionary

  • intravenous digital subtraction angiography — a type of phlebography that uses electronic circuitry to subtract the background of bone and soft tissue to provide a useful image of the veins injected with contrast medium …   Medical dictionary

  • digital subtraction — a radiological technique that enhances X ray images, most commonly of blood vessels (see angiography). A digitized image is taken before the contrast medium (a ‘mask’) is added, and this is subtracted by computer from the images taken after… …   The new mediacal dictionary

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