The correlation between stiffness and viscoelasticity of the myometrium in adenomyosis: a prospective study

Background: Shear wave elastography (SWE) can be used to detect the stiffness of the myometrium and lesion of the uterus, shear wave dispersion (SWD) can be used to detect the viscoelasticity, and magnetic resonance imaging (MRI) can be used to detect the water content. This study aimed to analyze the correlation between the stiffness, viscoelasticity, and water content of the myometrium and lesions of the uterus in individuals with adenomyosis (AM) and predict the diagnostic efficacy of stiffness and viscoelasticity in AM. Methods: Between October 2023 and December 2023, this prospective study enrolled patients with AM and those with a healthy uterus whom were admitted to Shengjing Hospital of China Medical University. The SWE, SWD, and MRI T2-weighted (T2W) images of patients with AM were analyzed, and the stiffness (E), viscoelasticity [shear wave dispersion slope (SWDS)], and water content (T2) of each myometrial segment and lesion of healthy and AM uteri were obtained, respectively. Continuous variables were analyzed using means, tests, and analysis of variance. The correlations between stiffness, viscoelasticity, and water content were analyzed by the Spearman coefficient. The diagnostic efficacy of stiffness, viscoelasticity, and other factors in AM were analyzed via logistic regression, and the diagnostic efficacy of stiffness and viscoelasticity in AM were analyzed via receiver operating characteristic (ROC) curves and the area under the curve (AUC), validating the logistic regression model with the E-value. Results: A total of 58 cases were included: 20 with AM and 38 with a normal uterus. There was a significant correlation between the stiffness (r=-0.981), viscoelasticity (r=0.885), microvascular flow (r=0.980), and water content in the AM lesion. The correlation between the stiffness (r=-0.909), viscoelasticity (r=0.805), and water content of the inner myometrium was significant. The stiffness of the middle (r=-0.654) and outer (r=-0.699) myometrium was correlated with water content, while viscoelasticity was not significantly correlated with water content. The stiffness (E value) of each myometrial segment was significantly different in both the normal uterine group and the AM group (P<0.001). The E of the inner myometrium (P=0.003), the E of the middle myometrium (P=0.048), and the uterine volume (P=0.010) were factors capable of diagnosing AM, with an AUC of 0.853, a sensitivity of 0.73, and a specificity of 1.00. Conclusions: There were statistically significant differences in the stiffness and water content of the inner, middle, and outer myometrium in patients with AM. Meanwhile, the stiffness of each myometrium and lesion, microvascular flow, and uterine size were correlated with water content and can be used as diagnostic factors for AM. Through use of SWE, AM can be accurately distinguished from a healthy uterus (clinical trial registration no. ChiCTR2300077978).