Asymptomatic vesicoureteral reflux detected by neonatal ultrasonographic screening

Renal ultrasonography was performed in 2,384 healthy and asymptomatic neonates. The definition and grading of hydronephrosis was according to the system of the Society for Fetal Urology. Voiding cystourethrography was performed in the cases with moderate to severe hydronephrosis or persistent mild hydronephrosis. In cases with vesicoureteral reflux (VUR), a dimercaptosuccinic acid (DMSA) renal scan was arranged immediately to evaluate the renal parenchyma. VUR was diagnosed in 30 infants with a prevalence of 1.26%; 7 had bilateral VUR. The male/female ratio was 4:1 and the right/left ratio was 1.85:1. Comparing with the abnormal ultrasonographic findings, VUR appeared ipsilaterally in 23 ureters and contralaterally in 14 ureters. Using ultrasonography for diagnosing VUR, the sensitivity, specificity, positive predictive value, and negative predictive value were 62.2%, 36.1%, 11.0%, and 88.2%, respectively. DMSA renal scan was performed in 31 refluxing kidneys, and congenital renal scarring was found in 9 (29.0%) kidneys. Six neonates underwent reimplantation surgery. We conclude that although ultrasonography is not a reliable tool for diagnosing VUR, it can detect many cases of VUR during the newborn stage using our screening program, which thus makes early treatment from the neonatal period possible. Whether our screening program can improve the outcome of VUR will require further follow-up.