Differential Diagnostic Value of Obstructive and Nonobstructive Azoospermia by Scrotal Ultrasound

Feasibility of high-frequency ultrasound for seminiferous tubule assessment and correlation of B-mode imaging with pathological findings in the testis in azoospermia

PURPOSE

To determine the feasibility of high-frequency ultrasound (HFUS) for assessing seminiferous tubules and to understand high-resolution B-mode images of the testes in cases of azoospermia.

METHODS

We verified how the histopathological images of testicular biopsy specimens can be observed using HFUS images and measurement analysis of seminiferous tubules was performed to 28 testes of 14 cases with azoospermia who underwent preoperative ultrasound and microdissection testicular sperm extraction (micro-TESE). The population consisted of obstructive azoospermia (OA) and non-obstructive azoospermia (NOA), including Sertoli cell-only syndrome (SCOS), and the other pathologies. Statistical verification of differences in seminiferous tubule diameters among preoperative ultrasound examination, ultrasound examination of pathological specimens, and histopathological specimens. We also examined the imagingpathology correlation via a case series presentation, aiming to identify imaging markers of testicular pathology and determine the possibility of predicting each condition.

RESULTS

A comparison between HFUS images and histopathology from the same biopsy specimens suggested that ultrasonography could be seen as stereoscopic images due to its significantly greater slice thickness. The diameters of tubules were generally larger in pathological tissues as compared to ultrasonographic findings in OA and SCOS, but not in the other conditions. Comparisons provided insights into the predictability of SCOS and revealed imaging findings such as gaps between tubules and decreased diameter reflective of testicular damage.

CONCLUSION

Seminiferous tubules can be observed however the diameter of seminiferous tubules varies in imaging and histopathology depending on the pathology. Imaging findings that reflect testicular damage and the predictability of SCOS were revealed in this study, but further verification is required.

Establishment and validation of a 5-factor diagnostic model for obstructive and non-obstructive azoospermia based on routine clinical parameters

Azoospermia is a serious leading male-factor cause of infertility in couples of childbearing age. The two main azoospermia types, obstructive (OA) and non-obstructive (NOA) azoospermia, differ in their treatment approaches. Therefore, their clinical diagnosis is extremely important, requiring an accurate, efficient, and easy-to-use diagnostic model. This retrospective observational study included 707 patients with azoospermia treated between 2017 and 2021, 498 with OA, and 209 with NOA. Hematological and seminal plasma parameters, hormone levels, and testicular volume were used in logistic regression analysis to evaluate and compare their diagnostic performance, results showed that the optimal diagnostic model is constructed by five variables including semen volume, semen pH, seminal plasma neutral α-glucosidase activity, follicle-stimulating hormone in the serum, and testicular volume, compared with follicle-stimulating hormone-based and testicular volume-based models. The 5-factor diagnostic model had an accuracy of 90.4%, sensitivity of 96.4%, positive predictive value of 90.6%, negative predictive value of 89.8%, and area under the curve of 0.931, all higher than in the other two models. However, its specificity (76.1%) was slightly lower than in the other models. Meantime, the internal 5-fold cross-validation results indicated that the 5-factor diagnostic model had a good clinical application value. This study established an accurate, efficient, and relatively accessible 5-factor diagnostic model for OA and NOA, providing a reference for clinical decision-making when selecting an appropriate treatment.