ARRT Patient Care Practice Exam

The least toxic contrast medium listed below is:

1. barium sulfate

2. metrizamide

3. ethiodized oil

4. meglumine diatriazoate

The correct answer is: metrizamide

The choice of metrizamide as the least toxic contrast medium is based on its chemical composition and the way it interacts with the body. Metrizamide is classified as an iodinated water-soluble contrast agent. This means it is designed to be more easily eliminated from the body compared to other contrast agents, which can minimize the risks of potential toxicity. In practice, metrizamide, especially in its non-ionic form, tends to produce fewer adverse reactions and has a lower incidence of complications compared to ionic contrast agents, as it is less likely to cause discomfort or allergic responses. The chemical properties of metrizamide allow for better tolerance by the patients, making it a safer option in imaging procedures, particularly for those with a history of contrast media responses. Other contrast media like barium sulfate, ethiodized oil, and meglumine diatriazoate have specific indications and greater risks associated with their use. Barium sulfate can cause constipation and, in certain cases, bowel obstruction if not properly managed. Ethiodized oil, while useful in certain imaging techniques, is fat-soluble and can lead to complications if it extravasates into the body tissues. Meglumine diatriazoate, commonly known as Diatrizoate,