Reduced differential renal function in scintigraphy predicted high‐grade vesicoureteral reflux in children with antenatal hydronephrosiss

Aim A top‐down approach is widely used for detecting vesicoureteral reflux ( VUR ) in children with febrile urinary tract infections. We evaluated the diagnostic value of renal scintigraphy in predicting VUR in children with antenatal hydronephrosis ( AHN ). Methods The voiding cystourethrogram ( VCUG ) and renal scintigraphy results of 125 AHN patients (76% male) admitted to the Children's Hospital of Helsinki University, Finland, from 2003 to 2013 were analysed. Of those, 94 had nonrefluxing hydronephrosis, nine had low‐grade VUR and 22 had high‐grade VUR . Results Scintigraphy was performed at a median age of 1.4 (0.8–15.6) months. In patients with high‐grade VUR , the differential renal function ( DRF ) of the worse kidney was significantly lower than in patients without VUR , with a median of 35% and interquartile range ( IQR ) of 20–45 versus 47% ( IQR : 44–49), (p < 0.001). There was no difference between patients with low‐grade VUR and patients without VUR (p = 0.181). DRF s below 44% showed a sensitivity of 73% and specificity of 79% and predicted significantly high‐grade VUR (odds ratio 9.82, 95% confidence interval 3.44–28.05, p < 0.001) in the univariate analysis. Conclusion A DRF below 44% predicted high‐grade VUR in patients with AHN and supported the decision to perform VCUG .