Contrast-Enhanced Voiding Urosonography in Pediatric Vescicoureteral Reflux: A Narrative Review

Contrast-enhanced voiding urosonography (ceVUS) is a radiation-free technique for evaluating pediatric vesicoureteral reflux (VUR), although urethral catheterization is required. This narrative review summarizes its technical principles, diagnostic performance, safety, limitations, and clinical applications. Comparative studies suggest broadly similar diagnostic performance between ceVUS, voiding cystourethrography (VCUG), and direct radionuclide cystography; some report higher detection rates or reflux grading with ceVUS, but formal equivalence or superiority has not been established. Continuous real-time observation and repeated filling–voiding cycles may facilitate detection of intermittent reflux and intrarenal reflux, whereas grade I reflux confined to a non-dilated distal ureter may be missed. ceVUS-detected intrarenal reflux has shown a topographic association with acute cortical defects on dimercaptosuccinic acid scintigraphy, although its prognostic significance remains uncertain. Beyond initial diagnosis, ceVUS has been used for follow-up after conservative or surgical treatment, renal transplantation, and radiation-free videourodynamics. Intravesical second-generation microbubble agents have shown favorable short-term safety and parental acceptance. Nevertheless, evidence is limited by heterogeneous protocols, operator dependence, imperfect reference standards, and scarce data on clinical outcomes. Overall, ceVUS is a promising radiation-free option for selected pediatric VUR pathways, while fluoroscopic imaging remains appropriate when detailed urethral or complex distal ureteral anatomy is required.