What radiographic procedure is used to rule out urethral injury?

• A. Retrograde urethrogram
• B. CT urography
• C. Ultrasound of the kidneys
• D. MRI pelvis

Answer: (A)

The main concept is quickly confirming urethral integrity in a trauma patient to guide catheterization and management. The retrograde urethrogram is the test of choice because it directly visualizes the urethral lumen by injecting contrast from the urethral opening under fluoroscopy. If the urethra is intact, the contrast fills the urethra and bladder without leaking; if there’s a disruption, contrast extravasates outside the urethral tract, signaling injury. This information is crucial before attempting any catheterization, as a disrupted urethra warrants avoiding blind catheter passage and often requires a suprapubic approach or surgical repair.

CT urography, ultrasound of the kidneys, and MRI pelvis don’t specifically assess urethral continuity in the acute setting as reliably or efficiently. CT urography focuses on the kidneys and collecting system, ultrasound assesses renal structures, and MRI pelvis is not routinely used emergently to evaluate urethral injury.