Role of ultrasound in the imaging of posterior urethral valves.

The intrinsic abnormalities of male urethra causing urinary obstruction are frequently responsible for renal insufficiency, sometimes present at birth. The rare but typical malformations such as the posterior urethral valves represent major deviations from the normal embryonic development, and require prompt identification and surgical correction. Since the symptoms and signs that suggest the presence of abnormalities of the urinary tract are sometimes vague and nonspecific, in the majority of cases voiding cystourethrography (VCUG) performed in children depicts a normal urethra. To prevent the X-ray hazard, voiding cystourethrosonography (VCUS), i.e. contrast-enhanced dynamic ultrasonography of the urinary tract, was introduced. This article reviews the possibilities, advantages and limitations of this new ultrasonographic technique performed consecutively in 231 0-15 year-old male patients, whose normal and obstructive urethral patterns were clearly visualized; the latter were all confirmed by VCUG and interventional cystourethroscopy.