Contrast media – effect, application & risks

Contrast media

In order to be able to implement special medical examination procedures in a meaningful way and as efficiently as possible for those affected, various aids are required. These chemical substances include in particular the so-called contrast media .

What are contrast media?

Contrast agents are substances that are not used directly to treat diseases and to eliminate the symptoms that occur. The prime purpose of contrast media is to aid in the detection of disease and abnormalities in organs.

In medicine, the use of contrast media is mainly limited to the medical-technical methods referred to as imaging processes. The contrast media are used in ultrasound and X-ray diagnostics as well as in magnetic resonance tomography . These techniques are also referred to as contrast imaging due to the need for contrast media.

Various contrast media must have very specific properties and should not have any effect on the organism. They are eliminated from the body in a completely natural way.

Application, effect & use

In addition to X-ray diagnostics and sonography, highly modern procedures such as magnetic resonance imaging are not performed without contrast media . Contrast media make it possible to better visualize individual morphological structures.

The physical laws of optics are used for contrast media. In this context, the aim is to darken certain anatomical structures using very special chemical particles in the contrast medium. A targeted modification of information that is transmitted by the examination device is possible via the formation of shadows. This is the basis for increasing the image quality of diagnostic contrast agent displays.

The individual contrast media have different levels of light and radiation absorption. In addition, the contrast media differ in their composition. They differ from each other in their molecular weight, osmolarity and viscosity. The medical-technical procedures take advantage of this and work with different contrast media in order to achieve the best possible quality of the images.

Contrast agents, which are ideal for MRI, for example, are based on artificially creating a difference in density. It is about the optical influence of metal ions that have a magnetic nature.

Substances used

Not all contrast media used are based on one and the same principle. Contrast media in radiology have either a high or low density and are referred to as X-ray negative or X-ray positive substances.

For the patient or patients, the contrast media appear as liquids that are introduced into the body either through the mouth or through an injection. In the medical field, however, numerous contrast media are administered that differ from one another in terms of their chemical and physical structure.

In X-ray diagnostics, contrast media are administered in the form of suspensions of barium sulfate. In addition, many contrast media for X-rays contain iodine.

In the field of examinations using ultrasound, on the other hand, completely different contrast media are preferred. In medical circles, these contrast media are known as so-called echo contrast enhancers. The contrast media usually contain bubbles of air or a well-tolerated gas and mostly resemble a foam. The internal organs are “inflated”, so to speak, which means that a better ultrasound examination can be carried out with these contrast media.

In magnetic resonance tomography, extracellular and intracellular contrast media have now proven their worth. The latter group of contrast agents is selected quite rarely. The particles referred to as superparamagnetic iron particles belong to this class of contrast media.

Substances that form a chemical compound with manganese are also administered. Extracellular contrast agents are typical imaging aids in MRI. In contrast to the intracellular (intra = inside) contrast media, these contrast media move outside the organ cells. These contrast agents contain gadolinium ions and accelerate the magnetization of the water in the tissues.

Risks & side effects

In general, modern contrast media are harmless and do not always accumulate in the organism. Therefore, health consequences of contrast media are excluded. As a rule, the contrast medium is excreted unnoticed in the normal way and does not cause any symptoms. Some people may develop an allergy or intolerance to contrast media. Other side effects of contrast media administered orally can be slight diarrhea or nausea . However, this is usually due to the large amount of liquid in which the contrast medium is dissolved.

Lisa Newlon
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Hello! I am Lisa Newlon, and I am a medical writer and researcher with over 10 years of experience in the healthcare industry. I have a Master’s degree in Medicine, and my deep understanding of medical terminology, practices, and procedures has made me a trusted source of information in the medical world.