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Early stages of pelvic organ prolapses are mainly associated with the pelvic floor disfunction as a result of elasticity changes in the connective tissues including the vaginal wall. In this study, for the first time we used a compression optical coherence elastography (C-OCE) method for assessing elasticity of the vaginal wall under prolapse conditions after intravaginal neodymium (Nd:YAG) laser treatment. C-OCE was used for a comparative ex vivo study of vaginal wall average values of stiffness (elastic Young’s modulus) in patients with age norm (n = 6), stage I–II prolapse (n = 5) without treatment and stage I–II prolapse post 1–2 months Nd:YAG laser treatment (n = 10). To verify the C-OCE data, the structural features of the submucosal connective tissue were identified morphometrically by Van Gieson staining using quantitative textural analysis of the state of collagen bundles. The results of a comparative evaluation of C-OCE and histological images demonstrate a statistically significant tissue stiffness decrease in vaginal wall prolapse compared to the age norm (73.5 ± 18.9 kPa vs. 233.5 ± 48.3 kPa; p < 0.05). This agrees with the histologically revealed increase in the space between the bundles of collagen fibers, which leads to a decrease in the uniformity of their arrangement. After Nd:YAG laser treatment, we observed statistically significant connective tissue stiffness increase compared to vaginal wall prolapse without treatment (152.1 ± 19.2 kPa vs. 73.5 ± 18.9 kPa; p < 0.05), which was associated with an increase in the local thickness of the collagen bundles, a change in their orientation, and an increase in the uniformity of their arrangement. The obtained results indicate that the C-OCE can be a robust method for detecting the early stages of vaginal wall prolapse and assessing the elastic modulus increase in the vaginal wall after laser treatment.

We present a real-time realization of OCT-based elastographic mapping local strains and distribution of the Young’s modulus in biological tissues, which is in high demand for biomedical usage. The described variant exploits the principle of Compression Optical Coherence Elastography (C-OCE) and uses processing of phase-sensitive OCT signals. The strain is estimated by finding local axial gradients of interframe phase variations. Instead of the popular least-squares method for finding these gradients, we use the vector approach, one of its advantages being increased computational efficiency. Here, we present a modified, especially fast variant of this approach. In contrast to conventional correlation-based methods and previously used phase-resolved methods, the described method does not use any search operations or local calculations over a sliding window. Rather, it obtains local strain maps (and then elasticity maps) using several transformations represented as matrix operations applied to entire complex-valued OCT scans. We first elucidate the difference of the proposed method from the previously used correlational and phase-resolved methods and then describe the proposed method realization in a medical OCT device, in which for real-time processing, a “typical” central processor (e.g., Intel Core i7-8850H) is sufficient. Representative examples of on-flight obtained elastographic images are given. These results open prospects for broad use of affordable OCT devices for high-resolution elastographic vitalization in numerous biomedical applications, including the use in clinic.

Early stages of pelvic organ prolapses are mainly associated with the pelvic floor disfunction as a result of elasticity changes in the connective tissues including the vaginal wall. In this study, for the first time we used a compression optical coherence elastography (C-OCE) method for assessing elasticity of the vaginal wall under prolapse conditions after intravaginal neodymium (Nd:YAG) laser treatment. C-OCE was used for a comparative ex vivo study of vaginal wall average values of stiffness (elastic Young's modulus) in patients with age norm (n = 6), stage I–II prolapse (n = 5) without treatment and stage I–II prolapse post 1–2 months Nd:YAG laser treatment (n = 10). To verify the C-OCE data, the structural features of the submucosal connective tissue were identified morphometrically by Van Gieson staining using quantitative textural analysis of the state of collagen bundles. The results of a comparative evaluation of C-OCE and histological images demonstrate a statistically significant tissue stiffness decrease in vaginal wall prolapse compared to the age norm (73.5 ± 18.9 kPa vs. 233.5 ± 48.3 kPa; p < 0.05). This agrees with the histologically revealed increase in the space between the bundles of collagen fibers, which leads to a decrease in the uniformity of their arrangement. After Nd:YAG laser treatment, we observed statistically significant connective tissue stiffness increase compared to vaginal wall prolapse without treatment (152.1 ± 19.2 kPa vs. 73.5 ± 18.9 kPa; p < 0.05), which was associated with an increase in the local thickness of the collagen bundles, a change in their orientation, and an increase in the uniformity of their arrangement. The obtained results indicate that the C-OCE can be a robust method for detecting the early stages of vaginal wall prolapse and assessing the elastic modulus increase in the vaginal wall after laser treatment. [ABSTRACT FROM AUTHOR]