Barium sulfate is a substance with a high impermeability. Therefore, it is used in radiology as a sparingly soluble suspension in the form of X-ray positive contrast agents. It is not absorbed and is suitable for the presentation of the digestive tract. Subsequently, the remedy is excreted unchanged as a white bowel movement again.
Barium sulfate is administered as an esophageal swallow to obtain physiological information. It enters the stomach via the esophagus in oral form and is then excreted via the digestive tract. Another possibility is the rectal introduction for the acquisition of morphological information.
The barium sulfate suspensions used in X-ray diagnostics differ in terms of their viscosity, particle size and concentration. In addition to barium sulphate, isotonizing agents such as sorbitol as well as thickeners and dispersants are used in order to avoid flocculation (flocculation).
The contrast agent is often used in combination with methylcellulose gels and carbon dioxide to cause airway inflation of the gastrointestinal tract. This simultaneous use of two agents is called a double contrast method. In this way, a better representation of the intestinal mucosa in relief form is achieved because the contrast agent alone only leads to a thin coating on the intestinal surface.
Contrast agents are used to display organs with X-ray examinations, which show only a small difference in density to the surrounding organ systems and tissues. Thus, the physicians are able to distinguish pathological processes and healthy tissue.
Since barium sulfate suspensions are not water- and fat-soluble, they are not absorbed by the body and excreted unchanged. The toxic effect of the starting material barium metal is very low.
Contrast agents can have undesirable side effects that manifest themselves in various organs and the skin. If an X-ray examination by means of contrast media is indicated, there are generally stricter requirements than with the therapeutic allocation of medications. Modern X-ray contrast agents undergo long-term compatibility studies before they are approved by the legislature. Doctors are also required to educate their patients about the potential risks.
Using contrast media, the physicians gain additional information that they would not receive without imaging techniques and the use of these funds. The additional information is divided into two categories: morphological (structural) and physiological (functional) information. A typical study for the former is the double contrast imaging of the colon by rectal instillation (dropwise administration) of a barium suspension. By subsequent air introduction into the intestine, the intestinal lumen (clear width) is visible through the filling and the negative contrast. This is due to the high permeability of the air for X-radiation. Morphological changes such as polyps, constrictions, inflammations and deposits are visible.
Functional information is obtained by awarding a Breischluck. So the doctors can determine agility disorders of the esophagus. Due to the high white luminosity, the examined organ or tissue is clearly distinguishable from the surrounding organ and tissue structures, which remain dark on the X-ray image.
Patients must be fasted for the exam, which means they can not eat and drink for several hours. In most cases, this contrast is performed in the morning if the patient has not yet had breakfast, so he only has to forgo food intake for a short time.
The treating physician must make a careful risk-benefit assessment before using this X-ray contrast medium, as serious foreign body reactions can occur if the barium sulfate suspension reaches the wrong place.
Use is contraindicated if there is perforation in the gastrointestinal area and there is a risk of aspiration (uptake) of the contrast agent. This is the case, for example, with fistulas or a perforated ulcer in the form of a deep-seated substance defect. In the case of this misallocation, the contrast medium enters the peritoneal organs, for example the liver, spleen, stomach, colon, uterus or ovaries (ovary). If barium sulfate enters the free abdominal cavity, life-threatening complications can occur.
In the case of an irrigoscopy (colon x-ray), an X-ray examination must be carried out 14 days after the biopsy has been performed. Non-indicated intraperitoneal administration may lead to death of the patient. The opposite of "peritoneal" is "retroperitoneal". Primarily retroperitoneal are all the organs that lie behind the abdominal cavity, such as ureters and kidneys. Secondary retroperitoneal are the organs connected to the dorsal abdominal wall. These organs include duodenum (small intestine following the stomach), pancreas (pancreas), and ascending and descending colon (ascending and descending colon).
Less dangerous and rare side effects are constipation, sweats, weakness, stomach cramps, itching, hives or redness. Also respiratory or swallowing complaints, hoarseness and temporary states of confusion are possible.