urethrogram

A urethrogram is a radiologic examination used to visualize the urethra by introducing contrast material and obtaining imaging, typically with fluoroscopy. The two main techniques are the retrograde urethrogram (RUG), in which contrast is injected into the distal urethra, and the voiding cystourethrogram (VCUG or voiding urethrogram), in which the bladder is filled with contrast and images are taken during urination to assess the urethra and bladder neck. In trauma, RUG is commonly performed first to evaluate for urethral injury; catheterization is performed with caution to avoid exacerbating injury.

Indications include evaluation of suspected urethral trauma or disruption, particularly after pelvic fractures; assessment of suspected urethral stricture causing obstructive voiding; planning of surgical or endoscopic intervention; evaluation for fistula formation; and, in children, VCUG is used to assess urinary tract anomalies such as vesicoureteral reflux.

Procedure basics involve sterile technique. For RUG, a urethral catheter may be used to inject a small amount of iodinated contrast and radiographs are obtained along the anterior and posterior urethra. For VCUG, the bladder is filled with contrast via catheter and radiographs are acquired as the patient voids, providing visualization of the posterior urethra and bladder neck. Interpretations focus on urethral caliber and course, the presence of strictures, disruptions or extravasation of contrast, and any associated fistulas.

Risks include urinary tract infection, allergic reaction to iodinated contrast, discomfort, and radiation exposure. Absolute contraindications are uncommon; however, contrast allergy and pregnancy require careful consideration. In the setting of suspected urethral injury, imaging goals balance diagnostic yield with the risk of additional injury.