Transrectal US and Endorectal MR Imaging in Partial and Complete Obstruction of the Seminal Duct System: A comparative study

Purpose: To evaluate transrectal ultrasonography (US) and MR imaging findings of infertile patients with suspected complete or partial obstruction of the seminal duct system. Material and Methods: Two hundred and eighteen infertile patients with low ejaculate volume were evaluated by transrectal US. Endorectal MR imaging was performed on 62/218 patients. Prostatic cysts, ejaculatory duct (ED) dilatation (>2 mm in width), ED calculi or calcifications, seminal vesicle (SV) dilatation (a.p. diameter >15 mm), SV hypo/agenesis (a.p. diameter <7 mm), SV cysts (>5 mm), vasal agenesis and chronic prostatitis (coarse calcifications, heterogeneity in prostate) were considered significant findings for obstruction of the seminal duct system. Results: Pathologic findings were detected in 75% and 61% of patients with azoospermia on transrectal US and MR imaging, respectively. Transrectal US and MR imaging did not reveal any pathologies in 64.7% and 59.1% of patients with nonazoospermia, respectively. The incidences of hypoplastic/atrophic SV (12/48 vs. 5/170), SV agenesis (6/48 vs. 1/170), vasal agenesis (5/48 vs. 1/170) were significantly higher in the azoospermic subgroup ( p < 0.002). Conclusion: US is a good method for initial evaluation of these patients – especially in complete obstruction. Endorectal MR imaging should be reserved for selected patients in whom results of transrectal US are not conclusive.