Contrast-Enhanced Voiding Urosonography for Diagnosis of Ectopic Ureters in Five Female Dogs

The aim of the study was to describe the implementation of contrast-enhanced voiding urosonography (CE-VUS), a new, alternative, radiation-free imaging technique, for diagnosing ectopic ureters (EUs) in dogs. Five dogs were presented for evaluation of recurrent urinary tract infections and urinary incontinence. All dogs were bright and alert on presentation, and physical examination findings, complete blood count, and serum biochemistry results were within reference intervals. Plain radiographs and conventional ultrasonography did not reveal any appreciable changes. Following aseptic urethral catheterization, CE-VUS was performed by infusing a second-generation microbubble-based ultrasound contrast agent into the urinary bladder. The contrast agent was observed in both ureters and pelvicalyceal systems in cases one and five and in the left ureter and pelvicalyceal system in cases two, three, and four. Displacement of the ureteral orifices was documented caudal to the bladder trigone in all dogs with EUs. Additionally, a ureterocele associated with the left EU was identified in case three. These findings were consistent with vesicoureteral reflux secondary to EUs. The diagnosis was confirmed by radiographic cystography and/or computed tomography excretory urography (CTEU). CE-VUS appears to be a useful, radiation-free imaging technique for evaluating urinary tract morphology and function in dogs. To the authors' knowledge, no previous studies have reported the clinical use of CE-VUS for the diagnosis of EUs in dogs.