Retrograde urethrogram
A retrograde urethrogram is a routine radiologic procedure used to image the integrity of the (typically male) urethra. The procedure involves the injection of a radiopaque dye (contrast agent) into the urethral meatus of the penis in conjunction with X-ray imaging of the pelvic area.
Leakage of the dye at any point between the bladder and tip of the penis suggests urethral injury (usually secondary to pelvic trauma) and is an indication for surgical intervention.
References: New England Journal of Medicine procedure videos: Male Urethral catheterization http://content.nejm.org/cgi/video/354/21/e22/
Ohio State University Patient Education Materials: Retrograde Urethrogram http://www.radiology.osu.edu/pdfs/ForPatients/Procedures_Conditions/IR_Procedures/retrograde_urethrogram.pdf