IEEE Trans Biomed Eng. 2024 Oct;71(10):2948-2955. doi: 10.1109/TBME.2024.3403799. Epub 2024 Sep 19.
Strain elastography and shear wave elastography are commonly used to quantify cervical elasticity. However, the absence of stress information in strain elastography causes difficulty in inter-session elasticity comparison, and the robustness of shear wave elastography is compromised by cervical tissue's high inhomogeneity.
To overcome these limitations, we develop a quantitative cervical elastography system by adding a stress sensor to a clinically used transvaginal ultrasound imaging system.
We record the cervical deformation in B-mode images and measure the probe-surface stress through the sensor. Then we quantify the strain using a customized algorithm and estimate the cervical Young's modulus through stress-strain linear regression.
In phantom experiments, we demonstrate the system's high accuracy (alignment with the quasi-static compression method, p-value = 0.369 > 0.05), robustness (alignment between 60°- and 90°-contact measurements, p-value = 0.638 > 0.05), repeatability (consistency of single sonographers' measurements, coefficient of variation < 0.06), and reproducibility (alignment between two sonographers' measurements, Pearson correlation coefficient = 0.981). Applying it to pregnant participants, we observe significant cervical softening (p-value < 0.001): Young's modulus decreases 3.95% weekly and its geometric mean value during the first (11 to 13 weeks), second, and third trimesters are 13.07 kPa, 7.59 kPa, and 4.40 kPa, respectively.
The proposed system is accurate, robust, and safe, and enables longitudinal and inter-examiner comparisons.
The system applies to different ultrasound machines with minor software updates, which allows for studies of cervical softening patterns in pregnancy for larger populations, facilitating insights into conditions such as preterm birth.
为了克服这些局限性，我们通过在临床使用的经阴道超声成像系统中添加压力传感器，开发了一种定量的宫颈弹性成像系统。
我们记录 B 模式图像中的宫颈变形，并通过传感器测量探头-表面压力。然后，我们使用定制的算法量化应变，并通过应力-应变线性回归估计宫颈杨氏模量。
在体模实验中，我们证明了该系统具有很高的准确性（与准静态压缩法一致，p 值=0.369>0.05）、稳健性（60°和 90°接触测量之间的一致性，p 值=0.638>0.05）、重复性（单个超声医师测量的一致性，变异系数<0.06）和可重复性（两名超声医师测量之间的一致性，Pearson 相关系数=0.981）。将其应用于孕妇，我们观察到宫颈明显变软（p 值<0.001）：杨氏模量每周降低 3.95%，第一（11 至 13 周）、第二和第三孕期的几何平均值分别为 13.07 kPa、7.59 kPa 和 4.40 kPa。
所提出的系统准确、稳健且安全，能够进行纵向和检查者之间的比较。
该系统只需进行少量软件更新即可应用于不同的超声机，这使得对妊娠中宫颈软化模式的研究可以针对更大的人群进行，有助于深入了解早产等情况。
