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.