Which contrast media are considered radiopaque?

The choice of diatrizoate as the correct answer is grounded in its properties as a contrast agent. Diatrizoate is an iodinated contrast medium commonly used in various imaging procedures, including X-rays and CT scans. It is classified as radiopaque because it contains iodine, which effectively absorbs X-rays and appears white on radiographic images. This high atomic number element allows the visualization of internal structures, making it crucial for detecting and diagnosing conditions within the body through imaging.

In contrast, CO2, room air, and oxygen do not possess the same radiopaque properties. For instance, CO2 is often used in certain types of imaging but is not radiopaque; it will show up as a darker area on X-ray images due to its lower density compared to surrounding tissues. Room air and oxygen are similarly not suitable for radiographic contrast as they also allow X-rays to pass through more readily than iodinated contrast agents, resulting in a lack of visibility on imaging. Thus, diatrizoate stands out as the solid choice for effective radiographic enhancement among the provided options.