Final answer:
The statement that retrograde urography involves direct injection of a contrast medium into the kidney through the skin is True. This technique is utilized for detailed imaging and differs from excretory urography, which uses intravenous injection and normal urine flow for the contrast medium to reach the urinary system.
Step-by-step explanation:
True or False, Retrograde urography differs from excretory urography in that the contrast medium is injected directly into the kidney by means of a percutaneous injection through the skin? The statement is True. Retrograde urography involves the direct introduction of a contrast medium into the urinary system via the ureter, usually by means of a catheter that is moved up through the bladder and ureter. This is different from excretory urography (also known as intravenous urography), where the contrast medium is injected into the bloodstream and is filtered naturally by the kidneys into the urine.
In excretory urography, the contrast is given intravenously and is subsequently excreted into the urinary system, following the normal flow of urine from the kidneys through the ureters to the bladder. Retrograde urography, on the other hand, is often used when there is a need for detailed imaging of the ureters and kidney pelvis or when excretory urography cannot be performed.