Contrast enhanced reflux sonography in children: a comparison to standard radiological imaging

The diagnosis of vesicoureteral reflux is routinely performed by voiding cystourethrography. Especially in the course of conservative treatment, the radiation dose might increase during the years. With the development of ultrasound echo enhancing agents we assessed their diagnostic efficacy for evaluation of vesicoureteral reflux to replace voiding cystourethrography with radiation-free ultrasound.

A total of 104 children with a mean age of 5.4 years were examined using echo enhancing ultrasound after informed consent was obtained. For control purposes, all children underwent standard voiding cystourethrography as well. The diagnosis of vesicoureteral reflux was positive when microbubbles appeared in the ureter or renal pelvis. The sonographic findings were correlated with those obtained by standard voiding cystourethrography.

Of the 208 ureter and renal units investigated vesicoureteral reflux was detected in 76 (37%) by both technologies. Diagnosis was made sonographically in 5 units and by voiding cystourethrography in 3. All reflux grades (I to V) could be identified. The specificity and sensitivity of the contrast reflux ultrasound were significantly high. The long contrast time of up to 30 minutes combined with the high contrast effect resulted in convincing images with high levels of diagnostic confidence.

Our results clearly demonstrate that the diagnostic accuracy of vesicoureteral reflux by contrast enhanced ultrasound is statistically significant compared to standard radiological voiding cystourethrography. Therefore, this methodology represents an exceptional approach to reduce the number of children being exposed to ionizing radiation especially during conservative followup.