Reactions to radiocontrast material

Abstract

The first relatively nontoxic, organic, iodinated contrast material (RCM) was created and successfully tested by Moses Swick, an intern from Mt. Sinai Hospital in New York City while on fellowship in Germany in 1929 (1). He produced a monoiodinated pyridone ring from which commercially prepared di-iodinated pyridone rings were available for the next 20 years. Swick also helped in the development of the tri-iodinated, completely substituted six-carbon ring that has been the standard since the 1950s. The first of these agents, whether as diatrizoate or iothalamate, was an ionic benzoate, iodinated at positions 2, 4, and 6 wi th substituted side chains at 3 and 5 to increase solubility (Fig. 1). With three iodines per molecule, it is fairly easy to reach a concentration of 300 mg I / m L which is necessary for most imaging. The cations of choice for these ionic compounds are sodium or the sugar, meglumine, or a combination of the two. These are relatively inexpensive compounds to produce, but the drawback is that for an ionic compound to achieve such a high concentration of iodine, it must be hypertonic relative to blood. In fact, these iodinated, ionic, conventional contrast agents are about five times the osmolality of plasma, and this h igh osmolality results in significant problems. The problems include nausea and vomit ing on injection, pain at the injection site, skin s loughing from inadvertent sc injection, and endothelial irritation and occasional