Appearance of Deflux implants with magnetic resonance imaging after endoscopic treatment of vesicoureteral reflux in children.

OBJECTIVE: With the increasing popularity of endoscopic treatment for vesicoureteral reflux (VUR) in children, dextranomer/hyaluronic acid copolymer (Deflux) implants are more frequently detected by magnetic resonance imaging (MRI). Such findings on MRI may be misinterpreted and lead to unnecessary intervention. The objective of this study was to characterize the appearance of Deflux implants on MRI.

MATERIALS AND METHODS: Between July 2001 and November 2007, hospital charts of patients with a history of Deflux injection for VUR were evaluated to identify those who had subsequent MRI studies. The indications were determined, and the appearance of Deflux implants analyzed and compared to findings on ultrasound, voiding cystourethrography and kidney ureter bladder radiography.

RESULTS: Of 893 patients who underwent endoscopic treatment for VUR, subsequently 16 patients (1.8%) had MRI scans. Twenty-seven Deflux implants were identified on MRI as bright structures on T2-weighted sequences only. Neither T1-weighted images nor excretory MR urography visualized the Deflux implants, which did not enhance with gadolinium. Deflux was not detected by kidney ureter bladder radiography; however, voiding cystourethrography and more reliably ultrasound could identify implants.

CONCLUSIONS: Deflux implants appear on MRI as bright structures on T2-weighted sequences. History of VUR/VUR treatment and the presence of a single urinary system should provide reassurance and prevent inappropriate intervention for misdiagnosed ureteroceles.