Detection of posterior urethral valves with voiding cystourethrosonography with echo contrast

Abstract

Purpose: Cystosonography with echo contrast is an imaging modality developed to avoid x-ray exposure during detection of vesicoureteral reflux. The main role of cystosonography has been limited to screening for reflux in the female and for followup of both sexes. In males the radiographic voiding cystourethrogram is still considered the gold standard for urethral evaluation. We determined whether cystosonography during the voiding phase (voiding cystourethrosonography) can adequately visualize the male urethra and differentiate the normal from the obstructed urethra.

Materials and methods: 100 males underwent cystosonography with echo contrast to detect vesicoureteral reflux. During the voiding phase the urethra was studied with ultrasound. The transperineal sagittal approach was chosen because the bladder neck and proximal part of the urethra were better visualized with the probe maintained coaxial to these structures. In every case in which ultrasound urethral imaging was considered abnormal a radiographic voiding cystourethrogram was performed for comparison, and the urethra was directly observed with cystourethroscopy. All patients with normal urethral imaging have been followed for 12 to 54 months (mean 32).

Results: Voiding cystourethrosonography visualized the voiding phase in all patients studied with the transperineal ultrasound approach. Of the 100 boys 8 were correctly diagnosed with posterior urethral valves. None of those with normal ultrasound imaging showed clinical signs suggestive of urethral obstruction and remained asymptomatic.

Conclusions: The male posterior urethra can be effectively visualized with voiding cystourethrosonography, which can differentiate normal from the pathological obstructive urethral findings. This new approach can be recommended as the primary imaging modality to detect vesicoureteral reflux for both sexes, limiting the role of conventional fluoroscopic voiding cystourethrogram only to confirmation of a pathological finding in the male patient with a suspected obstructed urethra.