Assessing Vaginal Wall Elasticity via Shear-Wave Elastography Using a Transrectal Linear Array High-Frequency Probe in Premenopausal versus Postmenopausal Women: A Cross-Sectional Feasibility Study

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Objectives: This study aims to evaluate the feasibility of transrectal high-frequency linear array shear wave elastography (SWE) for assessing vaginal wall elasticity in women and to investigate potential differences in segmental elasticity values between premenopausal and postmenopausal populations. Methods: This cross-sectional study included 228 women (164 premenopausal and 64 postmenopausal) who underwent gynecological ultrasound examinations at Hubei Maternal and Child Health Hospital from December 2024 to January 2025. Transrectal linear array high-frequency ultrasound examinations were performed by two ultrasound technicians. Tissue stiffness was assessed using Young's modulus measurements obtained from six standardized vaginal wall segments: upper, middle, and lower regions of both anterior and posterior walls. Inter-rater reliability was assessed by calculating the intraclass correlation coefficient (ICC). Results: Linear mixed-effects modeling adjusting for age and BMI demonstrated that postmenopausal women exhibited significantly higher Young's modulus values (kPa) in the middle anterior wall (14.59 ± 3.93 vs 12.88 ± 3.87 kPa; adjusted P = 0.003, FDR q = 0.009) and middle posterior wall (14.87 ± 4.09 vs 13.28 ± 4.25 kPa; adjusted P = 0.013, FDR q = 0.026) compared with premenopausal women. Intra-group analysis revealed a significant proximal-to-distal stiffness gradient along the anterior wall in both premenopausal (P < 0.001) and postmenopausal (P = 0.001) groups, whereas the posterior wall displayed spatial homogeneity (P > 0.10). Inter-observer reliability was excellent, with ICCs ranging from 0.83 (0.68-0.94) to 0.95 (0.88-0.98) (P < 0.001). Conclusion: Transrectal SWE is a reliable, non-invasive method for evaluating segment-specific vaginal elasticity. Our study showed that postmenopausal tissue stiffening is localized to the middle vaginal canal rather than pan-vaginal, with an anterior proximal-to-distal elasticity gradient. While these findings advance understanding of regional biomechanical specialization, future large-scale, age-matched, and multicenter studies are required to validate these results and establish clinical diagnostic thresholds.