BACKGROUND: Congenital absence of the vas deferens is an important cause of obstructive azoospermia, and the lack of an imaging diagnostic test is a critical problem. The aim of this study is to discuss the use of ultrasonography in congenital absence of vas deferens, including dysplasia of the epididymis and the seminal vesical.

MATERIAL AND METHODS: Five fresh spermatic cord specimens were detected by ultrasonography (US) to evaluate the image of the spermatic cord segment of the vas deferens. Fifty normal males had scrotal US to confirm whether the normal spermatic cord segment of the vas deferens can be detected and to measure the internal and external diameter on the long axis view. Forty-six males clinically diagnosed as having congenital absence of vas deferens underwent scrotal US to evaluate the spermatic cord segment of the vas deferens and the epididymis. The seminal vesicals were detected with transrectal ultrasonography. We evaluated images of the vas deferens, epididymis, and seminal vesical.

RESULTS: Scrotal ultrasonography can distinguish the vas deferens from the other cord-like structures in the spermatic cord, and the vas deferens has a characteristic image. Scrotal ultrasonography detected all 50 normal males and measured the diameter. No statistically significant difference was found between the left and right measurements. In the 46 patients, the following anomalies were observed: 1) 42 cases of congenital bilateral absence of vas deferens; 2) 2 cases of congenital unilateral absence of the vas deferens; and 3) 1 case of congenital segmental absence of the vas deferens. All 46 cases were accompanied with epididymis and seminal vesical anomalies.

CONCLUSIONS: The spermatic cord segment of the vas deferens can be detected by US, which is a valuable tool in diagnosis of congenital absence of the vas deferens. Seminal vesical and epididymis anomalies often associated with congenital absence of the vas deferens were revealed by ultrasonography.

Keywords: Epididymis - diagnostic imaging, Male Urogenital Diseases - diagnostic imaging, Spermatic Cord - diagnostic imaging, Ultrasonography - methods, Vas Deferens - diagnostic imaging