contrast medium

medium /me·di·um/ (me´de-um) pl. mediums, me´dia   [L.]

1. a substance that transmits impulses.

2. culture medium; see under C.

3. a preparation used in treating histologic specimens.

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active medium  the aggregated atoms, ions, or molecules contained in a laser's optical cavity, in which stimulated emission will occur under the proper excitation.

clearing medium  a substance to render histologic specimens transparent.

contrast medium  a radiopaque substance used in radiography to permit visualization of internal body structures.

culture medium  see under C.

dioptric media  refracting media.

disperse medium , dispersion medium, dispersive medium the continuous phase of a colloid system; the medium in which the particles of the disperse phase are distributed, analogous to the solvent in a true solution.

nutrient medium  a culture medium to which nutrient materials have been added.

refracting media  the transparent tissues and fluid in the eye through which light rays pass and by which they are refracted and focused on the retina.

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contrast medium

n.

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. Also called contrast agent.

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Contrast medium

A chemical substance used to make an organ or body part opaque on x ray.

Mentioned in: Hysterosonography

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contrast medium,

a substance that is injected into the body, introduced via catheter, or swallowed to facilitate radiographic imaging of internal structures that otherwise are difficult to visualize on x-ray films. Contrast media may be either radiopaque or radiolucent. Also called contrast agent.

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contrast

radiographically the degree of perceptible difference between two color tones. Black and white images on the one film is said to be high contrast; an all gray film has low or nil contrast.

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contrast agents

contrast agents are used for injection into the vascular system for either a local visualization of a system or organ or for outlining an excretory system. Radiolucent (negative) contrast media are gases such as air, oxygen or carbon dioxide. The radiopaque (positive) contrast media include the insoluble salt barium sulfate and a variety of organic iodine compounds.

Barium is used for gastrointestinal studies. Water-soluble, iodinated contrast media excreted by the kidneys are used for many procedures, including all types of angiography and for intravenous and retrograde urography. Those excreted by the liver are used for oral or intravenous cholangiography or cholecystography. New, nonirritant iodine compounds have been developed for myelography. Oily iodinated media are used for lymphangiography and bronchography.

double contrast

the use of two contrast agents or two routes of administration in the one patient. For example, radiopaque dye and then air in the urinary bladder.

contrast materials

see contrast agents (above).

contrast medium

a substance used in radiography to permit visualization of internal body structures. Called also contrast agent, contrast material.

negative contrast

a contrast material that is not radiopaque such as air or carbon dioxide.

contrast pattern

the pattern made by the contrast agent. Includes confined extension patterns in diverticula and similar confined spaces, and unconfined extensions, e.g. in bladder rupture.

positive contrast

the use of a contrast material that is radiopaque such as barium sulfate and iodinated products.

triple contrast

the use of three contrast media or routes in the one patient at the one time.

water-soluble contrast agents

agents used for injection into the vascular system for either a local visualization of a system or organ or for outlining an excretory system. In the past these have consisted mostly of iodine preparations which are irritant and cause tissue damage so that they must be injected intravenously. However, there are now available some recently developed water-soluble iodine preparations that are nonirritant and which can be used in myelography. See also contrast.

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medium

pl. media, mediums [L.]

1. an agent by which something is accomplished or an impulse is transmitted.

2. a substance providing the proper nutritional environment for the growth of microorganisms; called also culture medium.

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basic nutritive medium

one adequate for the growth requirements of most bacteria.

contrast medium

a radiopaque (positive) substance, or (negative) gases used in radiography to permit visualization of body structures.

culture medium

a substance used to support the growth of microorganisms or other cells.

dioptric medium

refracting medium (see below).

disperse medium, dispersion medium

the continuous phase of a colloid system; the medium in which a colloid is dispersed, corresponding to the solvent in a true solution.

enriched medium

modification of a basic medium for the growth of fastidious bacteria. Common additions are blood, serum or egg yolk.

indicator medium

a type of bacteriological medium which may contain a fermentable sugar plus a pH indicator that gives a color change. It is used to identify bacteria on the basis of a characteristic biochemical reaction.

refracting medium

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.

medium sausage

a technique for examining meat for bacterial contamination. The solid medium is made up in the form of a sausage and slices are removed from it after application of the exposed end to the suspect meat.

selective medium

formulated to facilitate the isolation of specific bacteria, they contain substances to inhibit growth of others.

transport medium

formulated to preserve a specimen, usually tissue or microbiological swab, and minimize bacterial overgrowth for the time necessary to transport it to the laboratory.

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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.

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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? Thanks