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

## TL;DR

This study compares two methods for detecting urinary reflux in young dogs and finds that a radiation-free ultrasound method is safe, accurate, and a good alternative to the standard X-ray method.

## Contribution

The study demonstrates that CE-VUS is a reliable radiation-free alternative to RCUG for diagnosing VUR in young dogs.

## Key findings

- CE-VUS showed 94.4% agreement with RCUG in detecting VUR in young dogs.
- CE-VUS had a 94.1% sensitivity and 94.4% specificity for VUR detection.
- CE-VUS identified six VUR cases not seen with RCUG and was well tolerated with no adverse effects.

## Abstract

This study evaluated the use of contrast-enhanced voiding urosonography (CE-VUS) as a radiation-free alternative to retrograde cystourethrography (RCUG) for detecting vesicoureteral reflux (VUR) in young dogs. While RCUG is the standard diagnostic method in veterinary medicine, CE-VUS has shown a high accuracy in pediatric human medicine. A total of 62 dogs aged 6 weeks to 12 months were examined using both CE-VUS and RCUG. This study assessed 124 ureterorenal units and found a 94.4% agreement between the two methods. CE-VUS demonstrated a 94.1% sensitivity and a 94.4% specificity, with a negative predictive value of 99%, indicating a strong reliability in ruling out VUR. Additionally, CE-VUS identified six cases of VUR not seen with RCUG. No adverse effects were reported, and CE-VUS was well tolerated. Its advantages include the absence of radiation, dynamic real-time imaging, and the ability to perform repeated evaluations. This study concludes that CE-VUS is a safe, accurate, and practical tool for diagnosing VUR in young dogs and may serve as a valuable alternative to RCUG in clinical practice.

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.