Contrast media (Diagnostic imaging)
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- MESH, Aug. 1, 2007(Contrast Media; scope note: substance used in radiography that allows visualization of certain tissues)
- Wilson web thes., Aug. 1, 2007(Contrast media; UF: Contrast agents; BT: Radiography)
- Dorland medical dict. online, Aug. 1, 2007(contrast medium: a substance that is introduced into or around a structure or tissues and has a significant difference from the structure or tissues in the extent of absorption of x-rays, thus allowing radiographic visualization. Called also contrast agent.)
- Wikipedia, Aug. 1, 2007(contrast medium: in a hospital setting, a contrast medium is any substance that is used to enhance the visibility of structures or fluids within the body. An example of this is the use of a radiopaque substance during an x-ray exam to highlight features that would otherwise be less distinguishable from nearby tissue. Another example is the use of air bubbles during an echocardiogram to search for a shunt in the heart.)
A contrast agent (or contrast medium) is a substance used to increase the contrast of structures or fluids within the body in medical imaging. Contrast agents absorb or alter external electromagnetism or ultrasound, which is different from radiopharmaceuticals, which emit radiation themselves. In X-ray imaging, contrast agents enhance the radiodensity in a target tissue or structure. In magnetic resonance imaging (MRI), contrast agents shorten (or in some instances increase) the relaxation times of nuclei within body tissues in order to alter the contrast in the image. Contrast agents are commonly used to improve the visibility of blood vessels and the gastrointestinal tract. The types of contrast agent are classified according to their intended imaging modalities.
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