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medium [me´de-um] (pl. mediums, me´dia) (L.)
1. an agent by which something is accomplished or an impulse is transmitted.
3. a preparation used in treating histologic specimens.
contrast medium a radiopaque substance used in radiography to permit visualization of body structures. Called also contrast agent.
a substance or preparation used to support the growth of microorganisms or other cells; called also medium
dispersive medium the continuous phase of a colloid system; the medium in which the particles of the disperse phase are distributed, corresponding to the solvent in a true solution.
refracting media the transparent tissues and fluid in the eye through which light rays pass and by which they are refracted and brought to a focus on the retina.
any internally administered substance that has a different opacity from soft tissue on radiography or computed tomography; includes barium, used to opacify parts of the gastrointestinal tract; water-soluble iodinated compounds, used to opacify blood vessels or the genitourinary tract; may refer to air occurring naturally or introduced into the body; also, paramagnetic substances used in magnetic resonance imaging.
A substance, such as barium or air, used in radiography to increase the contrast of an image. A positive contrast medium absorbs x-rays more strongly than the tissue or structure being examined; a negative contrast medium, less strongly.
contrast medium Contrast, contrast agent Imaging A substance with a density–eg, a dye or signal differing from that of the organ or structure being imaged, which allows delineation of contour abnormalities; CMs that are more radiopaque–eg with barium or iodine—than the organ or structure being analyzed are known as positive CM, while those that are less radiopaque–eg, with air, are known as negative CM. See Radiopaque contrast.
con·trast me·di·um (kon'trast mē'dē-ŭm)
Any internally administered substance that has a different opacity from soft tissue on radiography or computed tomography; used to opacify parts of the gastrointestinal tract, blood vessels, or the genitourinary tract.
contrast medium Any substance offering greater resistance to the passage of X rays than soft tissues that can be introduced into a hollow organ so as to outline its interior during radiology. Contrast media include a suspension of a barium salt for the intestine (barium meal or enema) and iodine-containing fluids for the blood vessels and urinary tract.
A chemical substance used to make an organ or body part opaque on x ray.
Patient discussion about contrast medium
Q. Has anyone had an allergic reaction to gadolinium dye, MRI contrast agents, I have had a severe reaction. I would like to know the long term effects of this dye. And if anyone else has had or heard of problems and reactions to it. Please answer me. Thank you
A. In 1969 I almost died from the IVP dye. I had no idea I was allergic and when I awoke I was in a "recovery room." The doctor told me to always tell any physicians/paramedics etc of my allergy status regarding the dye. I now have chronic back pain, have a history of cancer in the family and the doctor wants to do a scan (including dye) but when I emphasized that I was allergic he backed off. Now I am wondering if there is anything else that can be done to test the bone (scan) without the dye. Any answers? ThanksMore discussions about contrast medium