During a double contrast cystogram, what is introduced into the bladder?

• A. Air and contrast media
• B. Only air
• C. Only contrast media
• D. Saline solution

Answer: (A)

Double-contrast cystography uses both a radiopaque contrast agent and a small amount of gas to create two different visual contrasts inside the bladder. The contrast medium opacifies the lumen, while the introduced air provides a negative contrast that expands and outlines the mucosal folds. This combination makes subtle mucosal irregularities, diverticula, or small lesions much easier to see. Introducing only air would not show the lumen clearly, while only contrast would be a single-contrast study and not provide the enhanced detail that gas offers. Saline wouldn’t serve as a radiopaque contrast.