Developments in X-Ray Contrast Media and the Potential Impact on Computed Tomography

Over the past 120 years, continuous developments in medical imaging has improved diagnosis and treatment for many diseases and has thereby improved treatment outcome and quality of life of many patients. The number of computed tomography (CT) examinations is today increasing by 4% per year worldwide, for a total of approximately 300 million CT scans per year. About 40% of CT scans are contrast enhanced. Intravenous iodinated contrast media are commonly used for contrast enhancement in CT scans to evaluate diseases and determine treatment response. The current gold standards for intravenous x-ray contrast media in CT or interventional angiography are iodinated low- and iso-osmolar compounds such as iopromide, iohexol, or iodixanol. Both classes have similar and favorable efficacy and safety profiles. Although iodine is biologically inert, iodinated contrast media can cause adverse reactions. In the future, one possibility would be to develop iodine-free contrast media that are better suited to higher x-ray tube voltage ranges, allowing greater flexibility for scanning protocols and thus leading to techniques that can provide equivalent diagnostic value at lower doses of radiation. Iodine-free contrast media would in addition provide an alternative to the market standard that could offer benefits for patients with known reactions to low-osmolality contrast media or thyroid disorders. The development of a new contrast medium, however, needs to be put in context with all upcoming technological advances in x-ray and CT. New detector technologies and artificial intelligence algorithms will in the future also improve the CT image reconstruction enabling the reduction of contrast media and radiation doses.