Which statement describes the types of contrast media used in radiography?

• A. Gas, liquid, and solid
• B. Anatomic, functional, and dynamic
• C. Negative, positive, and double
• D. Soft, hard, and neutral

Answer: (C)

Contrast media in radiography are categorized by how they alter X-ray attenuation. Negative contrast media, such as air or CO2, are less dense than surrounding tissues and appear darker on the image, creating radiolucent regions. Positive contrast media, like iodine-based agents or barium, are more radiopaque and show up as bright white areas on the image. Double-contrast studies use both a positive agent and a negative agent to provide complementary detail, often enhancing visualization of mucosal surfaces by outlining both the lumen and the wall. The other descriptions describe physical states or study types, not how contrast media are classified for imaging, so they don’t fit this context.