Postnatal imaging of prenatally detected hydronephrosis—when is voiding cystourethrogram necessary?
To evaluate whether grade 4–5 vesicoureteral reflux (VUR) can be predicted from renal ultrasound (RUS) findings and perform voiding cystourethrograms (VCUGs) only on high-risk patients.
The RUS and VCUG images of infants with prenatally detected hydronephrosis admitted to our institution between 2003 and 2013 were re-evaluated. The UTI episodes were collected retrospectively from patient journals. Patients with complex urinary tract anomalies were excluded.
One hundred eighty, 44 female and 136 male, patients (352 renal units (RU)), 23 (30 RU) of them having grade 4–5 VUR, were included. The median age of the patients at the time of the RUS was 1.3 (0.1–3.0) months and the median follow-up time was 2.0 (0.1–11.2) years.
In multivariate analysis, a visible ureter (OR 12.72; CI 5.33–32.04, p < 0.001) and shorter renal length (OR 2.67; CR 1.50–4.86, p < 0.001) in RUS predicted grade 4–5 VUR while a visible ureter predicted UTIs (OR 5.75; CI 2.59–12.66, p < 0.001).
A three-grade risk score for high-grade VUR was developed based on the RUS findings and the patients were categorized into low-, intermediate-, and high-risk groups. The incidence of grade 4–5 VUR was 2.9% in the low-risk, 12.2% in the intermediate-risk, and 52.2% in the high-risk group. The sensitivity and specificity for detecting grade 4–5 VUR were 79 and 82%, respectively.
In patients with antenatally detected hydronephrosis, a visible ureter and reduced renal length in RUS are significant risk factors for high-grade VUR. A RUS-based risk scoring would probably reduce the proportion of unnecessary VCUGs.
KeywordsChildren Hydronephrosis Prenatal Renal ultrasonography Vesicoureteral reflux
We would like to thank Mitja Lääperi, M.Sc., for the biostatistical expertise in our study.
Compliance with ethical standards
The study protocol was approved by the ethics committee at Helsinki University Hospital.
Conflict of interest
The authors declare that they have no conflict of interest.
- 6.Evans K, Asimakadou M, Nwankwo O, Desai D, Cherian A, Mushtaq I, Cuckow P, Duffy P, Smeulders N (2015) What is the risk of urinary tract infection in children with antenatally presenting dilating vesico-ureteric reflux? J Pediatr Urol 11:93.e1–93.93.e6Google Scholar
- 9.St Aubin M, Willihnganz-Lawson K, Varda BK, Fine M, Adejoro O, Prosen T, Lewis JM, Shukla AR (2013) Society for fetal urology recommendations for postnatal evaluation of prenatal hydronephrosis—will fewer voiding cystourethrograms lead to more urinary tract infections? J Urol 190:1456–1461CrossRefPubMedGoogle Scholar
- 10.Nguyen HT, Herndon CD, Cooper C, Gatti J, Kirsch A, Kokorowski P, Lee R, Perez-Brayfield M, Metcalfe P, Yerkes E, Cendron M, Campbell JB (2010) The Society for Fetal Urology consensus statement on the evaluation and management of antenatal hydronephrosis. J Pediatr Urol 6:212–231CrossRefPubMedGoogle Scholar
- 11.Nguyen HT, Benson CB, Bromley B, Campbell JB, Chow J, Coleman B, Cooper C, Crino J, Darge K, Herndon CD, Odibo AO, Somers MJ, Stein DR (2014) Multidisciplinary consensus on the classification of prenatal and postnatal urinary tract dilation (UTD classification system). J Pediatr Urol 10:982–998CrossRefPubMedGoogle Scholar
- 16.Lebowitz RL, Olbing H, Parkkulainen KV, Smellie JM, Tamminen-Möbius TE (1985) International system of radiographic grading of vesicoureteric reflux. International Reflux Study in Children. Pediatr Radiol 15:105–109Google Scholar