We report here the results of a longitudinal study of cervix stiffness during pregnancy. Thirty women, ages ranging from 19 to 37 years, were scanned with ultrasound at five time points beginning at their normal first-trimester screening (8-13 weeks) through term pregnancy (nominally 40 week) using a clinical ultrasound imaging system modified with a special ultrasound transducer and system software. The system estimated the shear wave speed (its square proportional to the shear modulus under idealized conditions) in the cervix. We found a constant fractional reduction (about 4% per week) in shear wave speed with increasing gestational age. We also demonstrated a spatial gradient in shear wave speed along the length of the cervix (softest at the distal end). Results were consistent with our previous ex vivo and in vivo work in women. Shear wave elasticity imaging may be a potentially useful clinical tool for objective assessment of cervical softening in pregnancy.

中文翻译：

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用剪切波弹性成像定量评估妊娠期间宫颈软化：体内纵向研究。

我们在此报告妊娠期间宫颈僵硬的纵向研究结果。30 名年龄从 19 岁到 37 岁不等的女性，使用经过改良的临床超声成像系统，在从正常妊娠早期筛查（8-13 周）到足月妊娠（通常为 40 周）的五个时间点进行了超声扫描。特殊的超声换能器和系统软件。该系统估计了子宫颈中的剪切波速度（其与理想条件下的剪切模量的平方成正比）。我们发现，随着胎龄的增加，剪切波速度持续小幅下降（约每周 4%）。我们还证明了沿子宫颈长度的剪切波速度的空间梯度（远端最软）。结果与我们之前对女性的体外和体内研究结果一致。剪切波弹性成像可能是客观评估妊娠期宫颈软化的潜在有用的临床工具。