A positive contrast agent that may be administered to a patient when barium sulfate is contraindicated is called:

A positive contrast agent that may be administered to a patient when barium sulfate is contraindicated is called:

• A. Aqueous iodine compound
• B. Iodine
• C. Air
• D. Barium thiosulfate

Answer: (D)

When a positive contrast agent is needed and barium sulfate can’t be used, iodinated contrast media is the substitute. These agents are water-soluble and contain iodine, making them radiopaque so they brightly outline structures on X-ray. Air provides a negative contrast and won’t replace a positive agent for opacifying a lumen, and barium thiosulfate isn’t a standard modern contrast used in practice. So the intended substitute is an aqueous iodine compound (iodinated contrast media), which is the appropriate way to achieve positive contrast when barium is contraindicated.

When a positive contrast agent is needed and barium sulfate can’t be used, iodinated contrast media is the substitute. These agents are water-soluble and contain iodine, making them radiopaque so they brightly outline structures on X-ray. Air provides a negative contrast and won’t replace a positive agent for opacifying a lumen, and barium thiosulfate isn’t a standard modern contrast used in practice. So the intended substitute is an aqueous iodine compound (iodinated contrast media), which is the appropriate way to achieve positive contrast when barium is contraindicated.