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). DRFs 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.