Why do some people need contrast agents? What are contrast agents?
Contrast agents are substances used in certain situations to provide information that may not otherwise be retrieved, for instance in the gastrointestinal tract or the spinal canal.
These contrast agents, like barium or iodine dyes, are injected intravenously or taken orally to enhance imaging of organs and blood vessels.
Your technologist will advise you beforehand if you need such contrast agents, depending on your health and medical condition.
Most contrast agents are perfectly safe. Some, like barium, may be slightly unpleasant to the taste, however they are otherwise harmless. Others, like iodine-based dyes, may in rare cases give hives, nausea or other limited adverse effects, however these are not common and can easily be treated.