Harmonic voiding urosonography with a second-generation contrast agent for the diagnosis of vesicoureteral reflux

Background Voiding urosonography with harmonic imaging (VUS HI) has been introduced as a sensitive and radiation-free imaging method for the diagnosis and follow-up of vesicoureteral reflux (VUR) in children. Objective The purpose of this study was to evaluate the sensitivity of VUS HI using a second-generation US contrast agent compared to standard voiding cystourethrography (VCUG). Materials and methods A total of 228 children with 463 kidney-ureter units (KUUs) underwent two cycles of VUS HI and two cycles of VCUG at the same session. VUS HI was performed after intravesical administration of 1 ml of a second-generation US contrast agent (sulphur-hexafluoride gas microbubbles, SonoVue, Bracco, Italy). For statistical analysis we used McNemar’s test, Student’s t -test and k coefficient tests. Results VUR was shown in 161/463 (34.7%) KUUs, 57 by both methods, 90 only by VUS, and 14 only by VCUG. Concordance in findings regarding the presence or absence of VUR was found in 359/463 (77.5%) KUUs ( k =0.40). The difference in the detection rate of reflux between the two methods was significant ( P