In Vivo Measurement of Cervical Elasticity on Pregnant Women by Torsional Wave Technique: A Preliminary Study (original) (raw)
Related papers
Cervical Stiffness Evaluated In Vivo by Endoflip in Pregnant Women
PLoS ONE, 2014
Objective: To determine the stiffness of the pregnant uterine cervix in vivo. Method: Five women in early pregnancy and six women in late pregnancy were included. The EndoFlip is a 1-m-long probe with a 12-cm-long bag mounted on the tip. The tip of the probe was inserted into the cervical canal. Sensors spaced at 0.5cm intervals along the probe were used to determine 16 serial cross-sectional areas of the bag. The diameter of the cervical canal could thereby be determined during inflation with up to 50 ml saline solution. Tissue stiffness was calculated from the geometric profiles and the pressure-strain elastic modulus (EP) at each sensor site. Three parts of the cervix were defined: the uterus-near part, the middle and the vaginal part. The EP max was defined as the highest EP detected along the cervical canal. Results: The EP max was always found in the middle part of the cervix. The median EP max was 243 kPa (IQR, 67-422 kPa) for the early pregnant women and 5 kPa (IQR, 4-15 kPa) for those at term. In the early pregnant women the stiffness differed along the cervical length (p,0.05) whereas difference along the cervix was not found for late pregnant women. A positive correlation coefficient (Spearman's rho) was established between the EPs of the uterus-near and the middle part (0.84), between the vaginal and the middle part (0.81), and between the uterus-near and the vaginal part (0.85). Conclusion: This new method can estimate the stiffness along the cervical canal in vivo. This method may be useful in the clinical examination of the biomechanical properties of the uterine cervix.
In vivo assessment of the biomechanical properties of the uterine cervix in pregnancy
Prenatal Diagnosis, 2013
Measuring the stiffness of the cervix might be useful in the prediction of preterm delivery or successful induction of labor. For that purpose, a variety of methods for quantitative determination of physical properties of the pregnant cervix have been developed. Herein, we review studies on the clinical application of these new techniques. They are based on the quantification of mechanical, optical, or electrical properties associated with increased hydration and loss of organization in collagen structure. Quasi-static elastography determines relative values of stiffness; hence, it can identify differences in deformability. Quasi-static elastography unfortunately cannot quantify in absolute terms the stiffness of the cervix. Also, the current clinical studies did not demonstrate the ability to predict the time point of delivery. In contrast, measurement of maximum deformability of the cervix (e.g. quantified with the cervical consistency index) provided meaningful results, showing an increase in compliance with gestational age. These findings are consistent with aspiration measurements on the pregnant ectocervix, indicating a progressive decrease of stiffness along gestation. Cervical consistency index and aspiration measurements therefore represent promising techniques for quantitative assessment of the biomechanical properties of the cervix.
Mechanical assessment of cervical remodelling in pregnancy: insight from a synthetic model
Journal of Biomechanics, 2015
During the gestation and the cervical remodelling, several changes occur progressively in the structure of the tissue. An increase in the hydration, disorganisation of collagen network and decrease in elasticity can be observed. The collagen structure disorganisation is particularly complex: collagen fibres turn thicker and more wavy as the gestation progresses in a transition from relatively straight fibres to wavy fibres, while pores between collagen fibres become larger and separated. Shear wave elastography is a promising but not yet fully understood tool to assess these structural changes and the cervix's ability to dilate. To this end, a numerical histo-mechanical model is proposed in the present study, which aims at linking variations in the microscopic histo-biomechanical processes with shear wave propagation characteristics. Parametric simulations are carried out for a broad range of mechanical and geometrical parameters. Results show a direct relationship between the histological and morphological changes during pregnancy and the viscoelastic behaviour of the tissue.
arXiv (Cornell University), 2023
What are the novel findings of this work? We develop a safe-in-pregnancy, operator-independent, and quantitative cervical elastography system based on transvaginal ultrasound imaging and stress measurement. The system shows high accuracy in phantom experiments and captures the expected decrease in cervical stiffness over pregnancy in a pilot population of pregnant patients. What are the clinical implications of this work? The system is safe, robust, and applicable to different ultrasound machines with minor software updates. It can be tested to define normal and abnormal cervical softening patterns in pregnancy for larger populations, which facilitates insights into cervical-elasticity-related diseases such as preterm birth with multiple potential clinical uses.
Transient Elastography to Assess the Cervical Ripening during Pregnancy: A Preliminary Study
Ultraschall in der Medizin - European Journal of Ultrasound, 2015
Purpose To explore the feasibility of transient elastography (TE) to quantify cervical stiffness changes during normal pregnancy and its spatial variability. Materials and Methods TE was used to quantify the cervical stiffness in four anatomical regions. 42 women between 17 and 43 years of age and at 6 – 41 weeks of gestation were studied. The stiffness was related to gestational age at the time of examination, interval from ultrasound examination to delivery and cervical length to evaluate the potential of TE to assess cervical ripening. In addition, a sensitivity analysis based on Cronbach’s alpha coefficient was carried out to assess the concordance between inter/intra-operator measurements. Results There were significant correlations between cervical stiffness measured in the four regions with gestational age and the remaining time for delivery. Results confirm stiffness variability within the cervix. No significant association was found between cervical length and stiffness in ...
Ultrasound in medicine & biology, 2015
The objective of this study was to determine whether estimates of ultrasonic attenuation could detect changes in the cervix associated with medically induced cervical remodeling. Thirty-six full-term pregnant women underwent two transvaginal ultrasonic examinations separated in time by 12 h to determine cervical attenuation, cervical length and changes thereof. Ultrasonic attenuation and cervical length data were acquired from a zone (Zonare Medical Systems, Mountain View, CA, USA) ultrasound system using a 5-9 MHz endovaginal probe. Cervical attenuation and cervical length significantly decreased in the 12 h between the pre-cervical ripening time point and 12 h later. The mean cervical attenuation was 1.1 ± 0.4 dB/cm-MHz before cervical ripening agents were used and 0.8 ± 0.4 dB/cm-MHz 12 h later (p < 0.0001). The mean cervical length also decreased from 3.1 ± 0.9 cm before the cervical ripening was administered to 2.0 ± 1.1 cm 12 h later (p < 0.0001). Cervical attenuation an...
Beyond cervical length: emerging technologies for assessing the pregnant cervix
American Journal of Obstetrics and Gynecology, 2012
Spontaneous preterm birth is a heterogeneous phenotype. A multitude of pathophysiologic pathways culminate in the final common denominator of cervical softening, shortening, and dilation that leads to preterm birth. A precise description of specific microstructural changes to the cervix is imperative if we are to identify the causative upstream molecular processes and resultant biomechanical events that are associated with each unique pathway. Currently, however, we have no reliable clinical tools for quantitative and objective evaluation, which likely contributes to the reason the singleton spontaneous preterm birth rate has not changed appreciably in &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;100 years. Fortunately, promising techniques to evaluate tissue hydration, collagen structure, and/or tissue elasticity are emerging. These will add to the body of knowledge about the cervix and facilitate the coordination of molecular studies and ultimately lead to novel approaches to preterm birth prediction and, finally, prevention.
Preliminary Results on the Preinduction Cervix Status by Shear Wave Elastography
Mathematics
The mechanical status of the cervix is a key physiological element during pregnancy. By considering a successful induction when the active phase of labor is achieved, mapping the mechanical properties of the cervix could have predictive potential for the management of induction protocols. In this sense, we performed a preliminary assessment of the diagnostic value of using shear wave elastography before labor induction in 54 women, considering the pregnancy outcome and Cesarean indications. Three anatomical cervix regions and standard methods, such as cervical length and Bishop score, were compared. To study the discriminatory power of each diagnostic method, a receiver operating characteristic curve was generated. Differences were observed using the external os region and cervical length in the failure to enter the active phase group compared to the vaginal delivery group (p < 0.05). The area under the ROC curve resulted in 68.9%, 65.2% and 67.2% for external os, internal os and...