Radiocontrast agents are typically iodine or barium compounds. These compounds work by altering the medical medium book pdf properties of nearby hydrogen nuclei.
Radiocontrast agents used in X-ray examinations can be grouped based on its use. Iodine-based contrast media are usually classified as ionic or non-ionic. Both types are used most commonly in radiology due to their relatively harmless interaction with the body and its solubility. Contrast media are primarily used to visualize vessels and changes in tissues on radiography and CT.
Contrast media can also be used for tests of the urinary tract, uterus and fallopian tubes. It may cause the patient to feel as if they have had urinary incontinence. It also puts a metallic taste in the mouth of the patient.
Modern intravenous contrast agents are typically based on iodine. Ionic agents were developed first and are still in widespread use depending on the requirements, but may result in additional complications.
Organic agents which covalently bind the iodine have fewer side effects as they do not dissociate into component molecules. Many of the side effects are due to the hyperosmolar solution being injected. The more iodine, the more “dense” the X-ray effect. Organic iodine molecules used for contrast include iohexol, iodixanol and ioversol.
Iodine-based contrast media are water-soluble. Modern iodinated contrast agents can be used almost anywhere in the body. Ionic contrast media typically, but not always, have higher osmolality and more side-effects. Non-ionic contrast media have lower osmolality and tend to have fewer side-effects.
Barium sulfate is mainly used in the imaging of the digestive system. The substance exists as a water-insoluble white powder that is made into a slurry with water and administered directly into the gastrointestinal tract.
Barium sulfate, an insoluble white powder is typically used for enhancing contrast in the GI tract. Depending on how it is to be administered the compound is mixed with water, thickeners, de-clumping agents, and flavourings to make the contrast agent. As the barium sulfate doesn’t dissolve, this type of contrast agent is an opaque white mixture.
After the examination, it leaves the body with the feces. In the picture it highlights the interior of the colon. An example of a technique using purely air for the contrast medium is an air arthrogram where the injection of air into a joint cavity allows the cartilage covering the ends of the bones to be visualized.