Comparison of Ultrasound and 99mTc-DMSA Scan Findings with Voiding Cystourethrography in Detecting Vesicoureteral Reflux in Children

Background: Vesicoureteral reflux (VUR) is a common urinary tract disorder in pediatrics and could increase the risk of severe complications. The aim of this study is to assess the efficacy of ultrasound (US) and 99mTc-DMSA scan in detecting VUR in comparison with voiding cystourethrography (VCUG) among children hospitalized with urinary tract infection (UTI).Methods: In this cross-sectional study, the total numbers of 540 children with UTI referred to Ali-Asghar children’s hospital were enrolled, from April 2017 to May 2019. All patients underwent US and VCUG , 99mTc-DMSA performed for some of them to detect VUR. Accuracy, sensitivity, specificity, negative predicted value (NPV), positive predicted value (PPV) and Kappa agreement coefficient was used to compare the US and 99mTc-DMSA with VCUG results. Results: Among 540 patients, VUR was detected in 143 children on VCUG including 90 (63 %) with grades III –V. US was abnormal in 97 of 143 patients (67.8 %) with confirmed VUR on VCUG and 99mTc-DMSA scan was abnormal in 41 of 69 (59 %) with VUR detected by VCUG. The overall accuracy, sensitivity, specificity, NPV and PPV for US were 61.30%, 67.83%, 58.94%, 37.31 and 83.57%, respectively. Among children with high grade VUR (grade III –V) on VCUG, the sensitivity, specificity and NPV of US were 80%, 58.2% and 93.60 respectively. However, when using both US and 99mTc-DMSA scan results for detecting the high grade VUR, the sensitivity, specificity and NPV were 92%, 42.30% and 93.20% respectively. Conclusion: Although neither the US nor the 99mTc-DMSA scan can alone be sufficiently accurate to detect all grades of VUR, US, especially when combined with 99mTc-DMSA scan has enough sensitivity and NPV for ruling out high-grade VUR. These results indicate that there is no need to do VCUG in children with normal US and 99mTc-DMSA scans.