written by: Victoria Trix•edited by: Leigh A. Zaykoski•updated: 12/28/2009
Digital subtraction angiography, or DSA, is used to look at images of blood vessels in the body by using an iodine based contrast. Learn about digital subtraction angiography history in this guide.
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Digital subtraction angiography history reveals that DSA is a method that improves on regular X-rays for seeing blood vessels following an injection of contrast made of radio-opaque solubles. This test is commonly used to see all arteries, veins and organs in the body with the use of computerized equipment and dyes. During this test, an IV is started while a person lies on an x-ray couch. A physician orders a dye injection, which is administered while heart rate and pulse are monitored. The x-ray equipment is used after the dye is injected to see all of the cardiovascular system, as well as other organs, with the computer. Some of the most common exams that are completed while DSA is used include arterial stents, angioplasty, angiograms, nephrostomy, and pacemaker installations.
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Digital Subtraction Angiography History
Digital angiography was developed by Castellanos, Robb and Steinberg according to Anthony Lalli, Department of Clinical Radiology for the Cleveland Clinic Foundation, making history in radiology in the early 1970’s. The photography subtraction was created as a way to help isolate vessels that otherwise cannot be seen in neuroradiology. Digital angiography is more or less a computerized tomography, and allows doctors and radiologists to see things they could not see in the past. The analog technique of subtraction angiography was used for many years and proved to be very unreliable. When digital subtraction angiography history was looked at, it was decided that another method should be made. The digital age allowed doctors to see more than ever before.
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Digital Subtraction Angiography Methods
To use digital subtraction angiography and see all there is to see, doctors began using computers to view the images. Simply put, an x-ray is taken before the dye is injected into the IV, and this is called the mask image. After the mask is made, the contrast is administered through the IV. A radiologist then uses equipment such as an image intensifier that continues taking pictures of the images at a regular rate. All the images after the mask image are taken away from the mask image, so that every vein and artery can be seen. When the entire procedure is completed, there can be hundreds of images depending on the type of procedure that is being completed during the angiography process. The first image is used as a reference, and all subsequent images are used to see differences in the area.
Before computers were used for this type of exam, radiologists simply took x-rays of the area before using a dye and after using a dye to see differences. This was very unreliable, and doctors were then forced to second guess decisions on diagnoses. The future of DSA may mean fewer patients will be using the exam. More radiologists and doctors are turning to computed tomography angiography (CTA) that produces 3D images and avoids some of the invasiveness of the procedures currently used.