Application of real-time shear wave elastography in the assessment of male infertility

Abstract

Background: Shear wave elastography (SWE) is recognized as a suitable imaging modality for identifying and characterizing testicular diseases. Recent exploration of SWE has focused on its feasibility in evaluating histopathological changes in the testicular parenchyma, with researchers increasingly focusing on the relationship between testicular stiffness and male fertility. In this study, we aimed to investigate the diagnostic value of SWE for distinguishing the relationship between spermatogenic defects and testicular stiffness in males of reproductive age.

Methods: This was a single center, cross-sectional study conducted from July 2017 to December 2019. A total of 1,116 consecutive patients who were voluntarily participating in in-vitro fertilization (IVF)-assisted conception at our hospital were recruited to the study. The cohort included 497 normozoospermia patients (Group I), 335 with normozoospermia and decreased motility and agglutination (Group II), 138 with oligozoospermia (Group III), 105 with non-obstructive azoospermia (Group-NOA), and 41 with obstructive azoospermia (Group-OA). We conducted SWE of each participant's testes and the testicular elastic modulus was calculated. The differences of testicular elastic modulus were compared among groups. Linear regression analysis was conducted to determine the correlation between sperm concentration and either testicular volume or testicular elastic modulus. Receiver operating characteristic (ROC) curves were drawn to evaluate the diagnostic efficiency of the maximum elastic modulus (Emax), mean elastic modulus (Emean), and maximum minus the minimum elastic modulus {E[max-min]}.

Results: The Emax, Emean, and E[max-min] increased gradually in groups I, II, III, and Group-NOA, with statistical differences between groups (P<0.01). Testicular volume was shown to be positively correlated with sperm concentration (r=0.476; P<0.01), while the Emax, Emean, and E[max-min] were negatively correlated with sperm concentration (r=-0.511, -0.357, and -0.524, respectively; P<0.01). The ROC curves were established based on the Emax, Emean, and E[max-min] and were used to distinguish Group-OA from Group-NOA. The areas under the ROC curve (AUCs) were 0.910, 0.863, and 0.900, respectively. We also used ROC curves to distinguish the severe oligozoospermia subgroup and Group-NOA from other groups, for which the AUCs were 0.877, 0.791, and 0.878, respectively.

Conclusions: The SWE is an effective supplement to routine ultrasound examination and can be used to diagnose and differentiate spermatogenetic dysfunction.

Keywords: Infertility; male; shear wave elastography (SWE); testis; ultrasonography.

Figure 1

SWE maps and ROC curves. (A) A 35-year-old male with normozoospermia. (B) A 26-year-old male with mild oligozoospermia. (C) A 26-year-old male with severe oligozoospermia. Locus deletions at sY152, sY157, sY239, sY242, sY254, and sY255 of Y-chromosome. Average testicular volume was 8.00 mL. Emax =4.7 kPa, Emean =1.85 kPa, Emin =1.05 kPa. (D) A 34-year-old male with NOA. Pituitary microadenoma (diameter =5 mm) was found with MRI. Average testicular volume was 1.13 mL. Testicular parenchyma was rough. Microlithiasis was found in both testes. Emax =8.15 kPa, Emean =3 kPa, Emin =1.1 kPa. (E) A 39-year-old male with OA. Average testicular volume was 17.48 mL. Testicular parenchyma was uniform. Bilateral epididymis enlargement, rough echo. Emax =2.3 kPa, Emean =1.55 kPa, Emin =1.0 kPa. (F) A 35-year-old male with KS, azoospermia. Chromosome karyotype was 47, XXY. Average testicular volume was 1.31 mL. Testicular parenchyma was rough. Microlithiasis was found in the right testis. Emax =9.75 kPa, Emean =2.85 kPa, Emin =0.5 kPa. (G) A 45-year-old male with sexual inversion, azoospermia. Chromosome karyotype was 46,XX. Average testicular volume was 0.82 mL. Testicular parenchyma was rough. Emax =4.35 kPa, Emean =2.4 kPa, Emin =1.3 kPa. (H) A 30-year-old male with idiopathic azoospermia. Average testicular volume was 8.64 mL. Testicular parenchyma was uniform. Emax =16.2 kPa, Emean =2.35 kPa, Emin =0.3 kPa. (I) A 27-year-old male with SCOS. Average testicular volume was 7.43 mL. Testicular parenchyma was uniform. Emax =3.3 kPa, Emean =1.85 kPa, Emin =1.2 kPa. (J,K) ROC curve of Emax, Emean, and E[max-min]. SWE, shear wave elastography; ROC, receiver operating characteristic; Emean, mean elastic modulus; Emin, minimum elastic modulus; Emax, maximum elastic modulus; E[max-min], maximum minus the minimum elastic modulus; NOA, non-obstructive azoospermia; OA, obstructive azoospermia; SWE, shear wave elastography; MRI, magnetic resonance imaging; KS, Klinefelter syndrome; SCOS, Sertoli cell-only syndrome.

Figure 2

Participant enrollment and distribution.