Low osmolar contrast agents, also known as contrast media, are chemicals that enable visualization of tissues or organs by enhancing density differences between lesions and surrounding tissue during radiography or other imaging techniques.
Iodine is the only element that has proven satisfactory for general use as an intravascular contrast medium for radiography. All iodinated contrast agents have a chemical structure that is based on a benzene ring containing three iodine atoms. Reductions in osmolality, in comparison to high osmolar contrast agents, are achieved by making compounds that are nonionic monomers (i.e., iopamidol, iohexol, iversol), nonionic dimers (i.e., iodixanol, ioxilan), or monoacidic dimers (i.e., ioxaglate). Iodixanol is iso-osmolar. Low osmolar contrast agents have been used in radiological diagnosis studies when the use of other contrast material could be detrimental to an individual's health (e.g., a history of adverse reactions to contrast material; a history of asthma or allergy; significant cardiac dysfunction; generalized severe debilitation; or sickle cell disease). Low osmolar contrast agents, which include iso-osmolar agents, have a lower risk of adverse reaction than high osmolar contrast agents.
