ABSTRACT

We aimed to show the usefulness of magnetic resonance imaging (MRI) in the evaluation of infertile men and its ability to distinguish obstructive from nonobstructive azoospermia.

Between April 2015 and February 2018, 45 azoospermic men underwent scrotal MRI. We evaluated the images with an emphasis on signal characteristics of the testis and morphologic changes typical for obstruction. Testicular volume (TV), apparent diffusion coefficient (ADC) value, T1 and T2 signal ratios (testis/muscle) were measured for every testis. On the basis of histologic results, patients were divided into two groups: obstructive azoospermia (OA) and nonobstructive azoospermia (NOA).

Testes of patients in the OA group had significantly lower ADC values (mean 0.876±101 ×10-3 mm2/s) than in the NOA group (mean, 1.114±147 ×10-3 mm2/s). TV was significantly higher in patients with OA (median, 17.61 mL; range, 11.1–38.4 mL) than in those with NOA (median, 10.5 mL; range, 5.2–22.2 mL). ROC analysis showed that both TV and ADC values were highly predictive for distinguishing between OA and NOA patients, with an area under the ROC curve of 0.82 and 0.92 respectively. A cutoff value of ≥12.4 mL could distinguish obstructive from nonobstructive azoospermia with a sensitivity of 92% and specificity of 63%, whereas for ADC measurements a cutoff value of ≥0.952 ×10-3 mm2/s exhibited a sensitivity of 81% and specificity of 90% There was no statistically significant difference in T1 and T2 signal ratios between both groups. Abnormalities typical for obstruction of the male reproductive tract (e.g., dilatation of ejaculatory ducts, prostatic or seminal vesicle cysts) were found in 78% of patients (14/18) in the obstructive group.

Scrotal MRI is a very effective tool for the evaluation of azoospermic men and may provide important information facilitating interventional treatment of infertility.