Ultrasonographic Appearance of the Deferent Ducts in Dogs without Genitourinary Disease

In veterinary medicine, deferent ducts are described as being visible on ultrasound only when pathologically enlarged. Abnormal ultrasonographic enlargement of the deferent ducts has primarily been described secondary to infectious and neoplastic diseases; however, no studies have evaluated the normal ultrasonographic features of these structures. This prospective observational study aimed to describe the ultrasonographic appearance of deferent ducts and assess ultrasound reliability in their identification in intact and neutered dogs without genitourinary disease. The study aimed also to compare ultrasonographic measurements with postmortem anatomical ones and to investigate the relationship between duct identification, size, and intrinsic factors of the patient. The study consisted of ex vivo and in vivo phases in which ultrasonographic assessments of the ducts were conducted at the level of the prostate in longitudinal (location 1) and transverse (location 2) planes and the inguinal canal (location 3) and scrotal region (location 4) in longitudinal planes. A total of 80 deferent ducts were included. The ducts were visible as paired tubular hypoechoic structures delimited by two thin hyperechoic lines, with a target-like appearance on the transverse plane. The deferent ducts were identified in 97.5% of our population in at least one location, with locations 1 and 2 being the most reliable ones. Identification of the ducts was independent of reproductive status; however, reproductive status appeared to be the most significant factor influencing deferent duct size, with neutered dogs exhibiting smaller deferent ducts.