In which position are the ureters best demonstrated contrast-filled during intravenous urography?

• A. Prone
• B. Supine
• C. Sitting
• D. Left lateral

Answer: (A)

The correct choice for the position that best demonstrates contrast-filled ureters during intravenous urography is the prone position. This position allows for optimal visualization of the ureters because gravity aids in the movement of the contrast medium through the urinary tract. When the patient is prone, the contrast can flow more uniformly due to the anatomical layout, ensuring that the ureters are well-filled and easily visualized on the radiographic images. This also helps to minimize superimposition of other structures, enhancing the overall clarity of the ureters in the imaging.

In other positions, such as supine, sitting, or left lateral, while it may be possible to see the ureters, gravity is not as effective in ensuring a clear contrast fill, which could lead to suboptimal imaging quality. Thus, the prone position is the most advantageous for demonstrating the ureters clearly.