Role of transrectal ultrasonography in the evaluation of azoospermic men with low-volume ejaculate.

Objective: The purpose of this prospective study was to evaluate the incidence of distal ejaculatory system defects with transrectal ultrasonography (TRUS) among patients evaluated for azoospermia.
Methods: Forty-two patients with low-volume ejaculate and azoospermia were evaluated by physical examination, serum follicle-stimulating hormone and luteinizing hormone level determination, karyotyping, selective screening for cystic fibrosis mutations, and TRUS.
Results: On physical examination, in 29 patients (69%), either 1 (12 patients) or both (17 patients) of the vasa deferentia could not be palpated. In the group of 17 patients with bilateral involvement of the vasa deferentia, the ultrasonographic imaging universally showed bilateral absence or hypoplasia of the seminal vesicles with bilateral agenesis of the vasa deferentia and nonvisualization of both ejaculatory ducts. In the patients with a unilateral abnormality on physical examination, the ultrasonographic imaging showed absence of the ipsilateral seminal vesicle in 7 patients and the hypoplastic seminal vesicle in 5. In the group of 13 patients with normal physical examination findings, a variety of obstructive causes were diagnosed by TRUS examination.
Conclusions: According to this study, TRUS appears to be a sensitive method for evaluating the anatomy of the distal ejaculatory system. Its safety and low costs make it a good alternative to the other invasive and expensive methods.