https://hdl.handle.net/10481/44696 2026-04-11T19:03:28Z https://hdl.handle.net/10481/101354 Viscoelastic model characterization of human cervical tissue by torsional waves Callejas Zafra, Antonio Manuel; Faris al Azzawi, Inas H; Melchor, J.; Rus Carlborg, Guillermo The understanding of changes in the viscoelastic properties of cervical tissue during the gestation process is a challenging problem. In this work, we explore the importance of considering the multilayer nature (epithelial and connective layers) of human cervical tissue for characterizing the viscoelastic parameters from torsional waves. For this purpose, torsional wave propagations are simulated in three multilayer cervical tissue models (pure elastic, Kelvin–Voigt (KV) and Maxwell) using the finite difference time domain method. High-speed camera measurements have been carried out in tissue-mimicking phantoms in order to obtain the boundary conditions of the numerical simulations. Finally, a parametric modeling study through a probabilistic inverse procedure was performed to rank the most plausible rheological model and to reconstruct the viscoelastic parameters. The procedure consist in comparing the experimental signals obtained in human cervical tissues using the Torsional Wave Elastography (TWE) technique with the synthetic signals from the numerical models. It is shown that the rheological model that best describes the nature of cervical tissue is the Kelvin–Voigt model. Once the most plausible model has been selected, the stiffness and viscosity parameters have been reconstructed of the epithelial and connective layers for the measurements of the 18 pregnant women, along with the thickness of the epithelial layer. https://hdl.handle.net/10481/44845 On the safety of elastography in fetal medicine: A preliminary study of hypoacusia Massó Guijarro, Paloma; Molina, Francisca; Rus Carlborg, Guillermo Elastography is a promising technology to provide additional clinical information on the cervical effacement to that obtained from Bishop test and conventional cervicometry by ultrasounds. Among the different techniques, transient, or acoustic radiation force elastography (ARFE) is becoming the most common commercial elastography technique. However, the high intensity of thr beam that ARFE emits to generate the necessary concentrated burst of acoustic radiation [1] to induce a tractable shear oscillatory displacement (see Figure 1), has raised some concerns about its potential teratogenous effects during pregnancy. This letter is aimed at opening a debate to assess the safety of this type of elastography, and in particular to provide a preliminary screening of cochlear damage in exposed fetus. This is the pre-peer reviewed version of the following article: Massó, P.; Molina, F.; Rus Carlborg, G. On the safety of elastography in fetal medicine: A preliminary study of hypoacusia. Ultrasound in Obstetric and Gynaecology: accepted author manuscript (2017), which has been published in final form at http://doi.dx.org/10.1002/uog.17429 . This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.