MRI of the epididymis: can the outcome of vasectomy reversal be predicted preoperatively?

Abstract

Objective: The purpose of this study is to describe the MRI findings seen with tubular ectasia of the epididymis and investigate whether MRI may predict vasal/epididymal tubular occlusion before vasectomy reversal.

Materials and methods: First, we compared epididymal T1 signal intensity (measured as percentage change relative to ipsilateral testis) in 24 patients with sonographically established tubular ectasia compared with 22 control patients (sonographically normal epididymides). Second, in a subset of patients with tubular ectasia who subsequently underwent surgery to restore fertility (n = 10), we examined the relationship between epididymal T1 signal intensity and surgical outcome. Vasovasostomy (simple vas deferens reanastomosis with high success rate) was possible when viable sperm were detected in the vas deferens intraoperatively. When no sperm were detected, vasal/epididymal tubular occlusion was inferred and vasoepididymostomy (vas deferens to epididymal head anastomosis, a technically challenging procedure with poorer outcome) was performed.

Results: In tubular ectasia, we found increased epididymal T1 signal intensity (0-77%) compared with normal epididymides (-27 to 20%) (p < 0.0001). In patients with tubular ectasia who underwent surgery (n = 10), we found higher T1 epididymal signal intensity in cases of vasal/epididymal occlusion (0-70%) relative to cases in which vasal/epididymal patency was maintained (0-10%) (p = 0.01). By logistic regression, relative epididymal T1 signal intensity increase above 19.4% corresponded to greater than 90% probability of requiring vasoepididymostomy.

Conclusion: Increased epididymal T1 signal intensity (likely due to proteinaceous material lodged within the epididymal tubules) at preoperative MRI in patients undergoing vasectomy reversal suggests vasal/epididymal tubular occlusion and requirement for vasoepididymostomy rather than vasovasostomy.

Keywords: MRI; epididymis; tubular ectasia; ultrasound; vasectomy reversal.