A Comparison of Contrast-Enhanced Voiding Urosonography (CE-VUS) and Contrast Retrograde Cystourethrography (RCUG) for the Detection of Vesicoureteral Reflux in Young Dogs

The aim of this prospective study was to evaluate contrast-enhanced urosonography (CE-VUS) as an alternative to radiographic retrograde cystourethrography (RCUG) in the detection of vesicoureteral reflux (VUR) in young dogs. A total of 62 dogs, ranging in age from 6 weeks to 12 months, and 124 ureterorenal units (UUs) were investigated for VUR using RCUG and CE-VUS. After a baseline gray-scale ultrasound (US) of the urinary tract, a second-generation ultrasound contrast agent (UCA), diluted in a bottle of normal saline, was instilled into the urinary bladder via a catheter and CE-VUS was performed. VUR was detected when microbubbles were observed in the ureter and/or in the renal pelvis. In addition, RCUG was performed on the same day. The findings obtained by CE-VUS and RCUG were concordant in 117/124 UUs (94.35%). No reflux was detected in 101/124 UUs (81.45%) using both methods. With RCUG as the standard of reference, the sensitivity of CE-VUS was 94.12%, and the specificity was 94.39%. The positive predictive value was 72.73%, and the negative predictive value was 99.02%. CE-VUS is highly sensitive for the detection of VUR in young dogs.