Which of the following radiologic examinations does not demonstrate function?

• A. Excretory urography
• B. Voiding cystourethrography
• C. Retrograde cystography
• D. Retrograde urography

Answer: (D)

Retrograde urography does not demonstrate function because it primarily involves the injection of contrast media directly into the renal pelvis via catheters. This method allows for the visualization of the anatomy of the urinary system but does not provide any information about the physiological processes or functional aspects of kidney activity, such as urine formation or excretion.

In contrast, excretory urography and voiding cystourethrography are specifically designed to evaluate the function of the renal system. Excretory urography assesses how the kidneys filter and excrete contrast, while voiding cystourethrography examines how the bladder fills and empties, providing insight into bladder function. Retrograde cystography also evaluates the bladder, but it documents anatomical details rather than functional dynamics. Thus, retrograde urography stands out as the examination that solely focuses on anatomy rather than function.