Contrast ultrasound in diagnosis of intrarenal reflux in children

Abstract

Vesicoureteral reflux (VUR) is one of the most common urinary tract anomalies in children and may be associated with reflux nephropathy (RN). Many studies have shown that intrarenal reflux (IRR) is an important risk factor for febrile urinary tract infections (UTI) and renal scarring and consequently, later, the development of hypertension and/or renal failure. The incidence of IRR diagnosed by fluoroscopic voiding cystourethrography (VCUG) ranges below 1% to a maximum of 10%. The diagnostic criterion for IRR in contrast-enhanced voiding urosonography (ceVUS) is the appearance of contrast microbubbles outside the contours of the renal collecting system and the entry of contrast into the renal parenchyma. Numerous studies have demonstrated the high diagnostic accuracy of ceVUS compared to VCUG in the detection of VUR. We have been using ultrasound methods for the diagnosis of VUR in our institution since 2006, and ceVUS was accepted and included in the Algorithm of diagnostic procedures for children with UTI by the Croatian Pediatric Nephrology Society in 2018. Initially, we detected IRR in only 2.3% of children with VUR, and since 2013, when we applied contrast-enhanced voiding urosonography, IRR has been detected in 11.9% of children with VUR. To date, there are no studies investigating the incidence of IRR with this method. The aim of this paper is to present the possibility of diagnosing IRR using contrast ultrasound, to describe the technique of performance and our vast personal experience.

Keywords

• vesico-ureteral reflux – complications
• diagnostic imaging; kidney – diagnostic imaging
• pathology; cicatrix – diagnostic imaging
• etiology; urinary tract infections – diagnostic imaging; diagnostic techniques