Elasticity Contrast Research Articles

Diagnostic yield of combined ACR TI-RADS and Sonoelastography in solid thyroid nodules in tertiary care center: A prospective cross-sectional Study

Background: Thyroid nodules are prevalent, and accurate differentiation between benign and malignant nodules is crucial for management. We aim to evaluate the effectiveness of combining Thyroid Imaging Reporting and Data System (TIRADS) scoring with strain elastography, specifically the Elasticity Contrast Index (ECI), to differentiate between benign and malignant thyroid nodules. Methods: This analytical cross-sectional study involved 77 patients with solid thyroid nodules identified through B-mode ultrasonography. ACR TI-RADS scores, ECI values, and combined scores were compared with Fine needle aspiration Cytology (FNAC) results. Statistical analysis was performed using SPSS, and Pearson correlation tests were conducted to assess the correlation with FNAC findings. Result: The TI-RADS scoring system has a sensitivity of 83.3%, a specificity of 66.1%, and a positive predictive value of 42.9% for distinguishing benign and malignant nodules. Strain elastography with ECI values has a sensitivity of 94.4%, specificity of 98.3%, PPV of 94.4%, and NPV of 98.3%. Combining ACR TI-RADS and strain elastography achieves a sensitivity of 100%, specificity of 66.1%, NPV of 100%, and PPV of 47.4%. Conclusion: The study emphasizes the benefits of integrating noninvasive methods like ultrasound elastography and ACR TI-RADS for improved diagnostic precision, minimizing invasion and patient discomfort. This strategy is particularly advantageous for TI-RADS 3 nodules and reduces unnecessary procedures. However, FNAC should be reasonable and validated for higher classifications.

Non-contact elasticity contrast imaging using photon counting.

Tissues' biomechanical properties, such as elasticity, are related to tissue health. Optical coherence elastography produces images of tissues based on their elasticity, but its performance is constrained by the laser power used, working distance, and excitation methods. We develop a new method to reconstruct the elasticity contrast image over a long working distance, with only low-intensity illumination, and by non-contact acoustic wave excitation. We combine single-photon vibrometry and quantum parametric mode sorting (QPMS) to measure the oscillating backscattered signals at a single-photon level and derive the phantoms' relative elasticity. We test our system on tissue-mimicking phantoms consisting of contrast sections with different concentrations and thus stiffness. Our results show that as the driving acoustic frequency is swept, the phantoms' vibrational responses are mapped onto the photon-counting histograms from which their mechanical properties-including elasticity-can be derived. Through lateral and longitudinal laser scanning at a fixed frequency, a contrast image based on samples' elasticity can be reliably reconstructed upon photon level signals. We demonstrated the reliability of QPMS-based elasticity contrast imaging of agar phantoms in a long working distance, low-intensity environment. This technique has the potential for in-depth images of real biological tissue and provides a new approach to elastography research and applications.

CELASTO (Cervical ELASTOgraphy) pilot study — the use of cervical elastography during pregnancy

BACKGROUND: Ultrasound assessment of cervical length is an integral part of a comprehensive examination during pregnancy, but it does not provide a complete picture of structural changes in the cervix. The use of E-Cervix elastography is a promising method to assess cervical remodeling throughout the gestation period. AIM: The aim of this study was to evaluate the possibility of using automated cervical elastography in clinical practice to analyze the main parameters of cervical elasticity and hardness in pregnancy. MATERIALS AND METHODS: This prospective pilot study included 136 patients with singleton pregnancies at gestational ages ranging from 7+0 to 41+0 weeks. Cervical elastography was performed using E-Cervix software of the W10 diagnostic ultrasound system (Samsung Medison Co., Ltd., South Korea) with evaluation of quantitative parameters such as hardness ratio, elasticity contrast index, internal os, external os. RESULTS: Correlation analysis showed that hardness ratio decreased with increasing gestational age (ρ = −0.439) and decreasing cervical length (ρ = 0.408; p 0.001). In the group of patients with cervical length less than 25 mm, there was a decrease in hardness ratio compared to the control group (48.0 vs. 63.8%, respectively; p 0.001). The elasticity contrast index score, which reflects cervical tissue heterogeneity, increased with gestational age and cervical shortening (ρ = 0.368 and −0.450, respectively), the parameter being higher in patients with cervical length less than 25 mm [4.73 (IQR 4.21–5.90); p 0.001]. The increase in internal os and external os with gestational age (ρ = 0.433 and ρ = 0.365, respectively; p 0.001) indicates softening of the cervix and is accompanied by its shortening. CONCLUSIONS: Results indicate decreased hardness and increased elasticity of the cervix with increasing gestational age and decreased cervical length. E-Cervix technology allows for assessing structural changes in the cervix throughout pregnancy, starting from early gestation.

Role of Sonoelastography in Differentiating Benign and Malignant Breast Lesions: A Prospective Study Comparing Elasticity Contrast Index and Tsukuba Score

Introduction: Breast cancer is the most common cancer occurring in women globally which is potentially curable if detected early. Ultrasound elastography is a dynamic technique that estimates tissue stiffness to differentiate between benign and malignant masses. Our study aimed to determine and compare the diagnostic accuracy of B mode Sonography, Elasticity contrast index, and Tsukuba score in differentiating malignant and benign breast masses. Methods: This was a prospective cross-sectional study done including 110 lesions in 102 patients in the age group of 15-73 years. The solid breast lesions seen on sonography were categorized according to the American College of Radiology Breast Imaging Reporting and Data System (ACR BI-RADS) and further evaluated with elastography using both Elasticity Contrast Index (ECI) and Tsukuba score with pathological diagnosis taken as the gold standard. The cut-off value of ECI was obtained. The diagnostic accuracy of B-mode sonography, ECI, and Tsukuba score was compared. Results: We found that B-mode sonography had a sensitivity of 85.7%, specificity of 100%, and accuracy of 96.9 %. The accuracy of Tsukuba scores for differentiating benign and malignant lesions was 81.2%. The cut-off value of ECI obtained was 2.8 and the accuracy was 81.8%. A statistically significant correlation (p < 0.05) existed between sonographic diagnosis, ECI, and Tsukuba score. Conclusions: B mode sonography had the highest diagnostic accuracy while ECI and Tsukuba scores were comparable. ECI can be used for breast masses using a cut-off of 2.8 to differentiate benign from malignant.

Cervical elastography in predicting spontaneous preterm birth in singleton pregnancy with a short cervix receiving progesterone treatment at 18 to 24 weeks’ gestation

Background A short cervix in the second trimester is known to increase the risk of preterm birth, which can be reduced with the administration of vaginal progesterone. However, some studies have suggested that a significant number of cases still experience preterm birth despite progesterone treatment. Objective This study was aimed to investigate the potential value of transvaginal cervical elasticity measured by E-Cervix as a predictor for spontaneous preterm birth (sPTB) in singleton pregnancies receiving progesterone treatment for a short cervix (CL ≤ 2.5 cm) diagnosed at 18 to 24 weeks’ gestation. Study design This prospective study was conducted at a single center premature high-risk clinic from January 2020 to July 2022. Singleton pregnancies with a short cervix at 18 to 24 weeks’ gestation were enrolled. Cervical elastography using E-Cervix was performed, and maternal and neonatal demographic characteristics, cervical length (CL), elasticity contrast index (ECI), cervical hardness ratio, mean internal os strain (IOS), and mean external os strain (EOS) were compared before and after progesterone treatment in sPTB and term birth groups. Multivariate logistic regression was used to analyze the association between elasticity parameters and spontaneous preterm birth. The screening performance of CL and optimal cervical elasticity parameters in predicting sPTB was evaluated using receiver-operating characteristic (ROC) curve analysis. Results A total of 228 singleton pregnant women were included in the study, among which 26 (11.4%) had sPTB. There were no significant differences in maternal characteristics and gestational age at enrollment between women with and without sPTB. At the start of progesterone treatment, there were no significant differences in cervical elasticity parameters between the two groups. After two weeks of progesterone treatment, women who had sPTB showed significantly higher levels of ECI, IOS, EOS (p = 0.0108, 0.0001, 0.016), and lower hardness ratio (p = 0.011) compared to those who had a full-term birth. Cervical length did not show significant differences between the two groups, regardless of whether progesterone treatment was administered before or after. Among the post-treatment cervical elasticity parameters, IOS and EOS were associated with a 3.38-fold and 2.29-fold increase in the risk of sPTB before 37 weeks (p = 0.032, 0.047, respectively). The AUROC of the combined model including CL, IOS, and EOS (0.761, 95% CI0.589–0.833) was significantly higher than the AUROC of CL alone (0.618, 95% CI 0.359–0.876). At a fixed false-positive of 13%, the addition of IOS and EOS in the CL model increased sensitivity from 34.6% to 57.6%, PPV from 25.7% to 36.5%, and NPV from 91.1% to 94.1%. Conclusion When assessing the risk of sPTB in singleton pregnancies with a short cervix receiving progesterone therapy, relying solely on cervical length is insufficient. It is crucial to also evaluate cervical stiffness, particularly the strain of the internal and external os, using cervical elastography.

Comparison of artificial intelligence, elastic imaging, and the thyroid imaging reporting and data system in the differential diagnosis of suspicious nodules.

Ultrasound is widely used for detecting thyroid nodules in clinical practice. This retrospective study aimed to assess the diagnostic efficacy of the American College of Radiology Thyroid Imaging Reporting and Data System (ACR-TIRADS), S-Detect, and elastography of the carotid artery for suspicious thyroid nodules and to determine the complementary value of artificial intelligence and elastography. Between January 2021 and November 2021, 101 consecutive patients with 138 thyroid nodules were enrolled in The First Hospital of China Medical University. All nodules were evaluated using ACR-TIRADS categories (TR), S-Detect, and elastography, and then the diagnostic performance of the different methods and the combined assessment were compared. The inclusion criteria were the following: (I) TR3, TR4, and TR5 nodules, which were defined as "suspicious nodules"; (II) patients who had surgical or cytopathological results after ultrasound examination; and (III) voluntary enrollment in this study. Meanwhile, the exclusion criteria were the following: (I) TR1 and TR2 nodules, (II) patients who had undergone fine-needle aspiration before ultrasound examination, and (III) inconclusive cytologic findings. A total of 71 patients (12 men and 59 women) with 94 suspicious thyroid nodules (42 benign nodules and 52 malignant nodules) were finally included in this study. S-Detect had a significantly better sensitivity than did ACR-TIRADS [S-Detect: 98.1%, 95% confidence interval (CI): 89.7-100.0%; ACR-TIRADS: 84.6%, 95% CI: 71.9-93.1%; P=0.036], but its specificity was much lower (S-Detect: 19.0%; 95% CI: 8.6-34.1%; ACR-TIRADS: 40.5%, 95% CI: 25.6-56.7%; P=0.032). The accuracy was not significantly different between S-Detect (62.8%; 95% CI: 52.2-72.5%) and ACR-TIRADS (64.9%; 95% CI: 54.4-74.5%) (P=0.761). The elasticity contrast index (ECI) was not definitively useful in identifying suspicious thyroid nodules (P=0.592). Compared with the use of ACR-TIRADS and S-Detect alone, the specificity (45.2%; 95% CI: 29.8-61.3%), positive predictive value (65.2%; 95% CI: 52.4-76.5%), accuracy (66.0%; 95% CI: 55.5-75.4%), and the area under the receiver operating characteristic curve (0.640; 95% CI: 0.534-0.736) of their combination were higher but not significantly so. At present, S-Detect cannot replace manual diagnosis, and the value of elastography of the carotid artery in diagnosing suspected thyroid nodules remains unclear.

Joint elicitation of elasticity of intertemporal substitution, risk and time preferences

AbstractThe elicitation of the elasticity of intertemporal substitution (EIS), discount factor and risk attitude parameters in dynamic models is of central importance to economics, finance and public policy. This paper suggests an alternative method to jointly elicit and estimate these three parameters using experimental data. We employ a new model based on dynamic quantile preferences, where individuals maximize the stream of future ‐quantile utilities, for . These preferences are simple, dynamically consistent and monotonic. In the quantile model, the risk attitude is captured by the quantile of the payoff distribution, while the EIS and the discount factor are related to the utility function describing individual's intertemporal behaviour, hence allowing for complete separability between risk, EIS and discount factor. The estimation of the parameters of interest uses a structural maximum likelihood method. Individual's risk aversion is estimated below the median. The discount factor is marginally smaller than estimates reported in the literature, and the EIS is slightly larger than one, which suggests that utility over time is concave. The estimates for the elasticity contrast with those reported by the existing studies using observational disaggregated data, which in general find an elasticity smaller than one.

Addition of Cervical Elastosonography to Cervical Length to Predict Preterm Birth in Pregnancy Women with Prior Preterm Birth: A preliminary prospective study.

To investigate the characteristics of cervical elastosonography in pregnancies and establish an ultrasound-based combing predictor for improving the prediction in pregnant women with prior-preterm birth who might ultimately undergo preterm birth (PTB). 169 singleton pregnancies with prior-preterm birth were examined by cervical elastography from January to November of 2021. According to the ultrasound image and result of the following-up, the patients were separated into preterm groups and full-term groups with or without cerclage. There were five elastographic parameters: Elasticity Contrast Index (ECI), Cervical hard tissue Elasticity Ratio (CHR), External Cervical os Strain rate (ES), Closed Internal Cervical os Strain rate (CIS), CIS/ES ratio and CLmin. Multivariable logistic regression was used to screen out the most significant predictors. The area under the receiver operating characteristic curve (AUC) was calculated to evaluate the ability of prediction. The PTB group without cerclage showed significantly softer cervix stiffness, while those with cerclage showed significantly harder. CHRmin with P < 0.05 in the univariate logistic regression analysis was screened as a more valuable cervical elastosonography parameter than other ones. The combination of CLmin and CHRmin in un-cerclage and integrating CHRmin, maternal age and pre-pregnancy BMI in cerclage presented good predictive value. The results of AUC were higher than CLmin, respectively (0.775 vs 0.734, 0.729 vs 0.548). The addition of cervical elastography parameters (such as CHRmin) might improve the ability to predict preterm birth in pregnant women with previous preterm delivery, which was better than using CL alone.

Cervical elastography: finding a novel predictor for improving the prediction of preterm birth in uncomplicated twin pregnancies.

This study set out to investigate a novel ultrasound parameter using cervical elastosonography for improving the prediction of spontaneous preterm birth (sPTB) in twin pregnancies. The study was comprised of 106 twin pregnancies from October 2020 to January 2022 in Beijing Obstetrics and GynecologyHospital. They were divided into two groups according to gestational age (GA) at delivery (delivery < 35weeks and delivery ≥ 35weeks). There were five elastographic parameters: Elasticity Contrast Index (ECI), Cervical Hardness Ratio (CHR), Closed Internal cervical ostium Strain rate (CIS); External cervical ostium strain rate (ES), CIS/ES ratio and Cervical Length (CL). All of the clinical and ultrasonic indicators with P < 0.1 were considered candidate indicators via univariate logistic regression. Based on the extracted unified combination of clinical indicators, the combinations of permutation with the candidate ultrasound indicators were performed step by step in multivariable logistic regression. The best ultrasound indicator with the lowest Akaike Information Criterion (AIC) and the highest Areas Under the receiver operating characteristic Curve (AUC) was chosen for establishing the prediction score. Over 30% (36/106) of those who delivered before 35weeks gestation. There were distinct differences in the clinical characteristics and cervical elastography parameters between the two groups. Seven major clinical variables were identified as a unified clinical indicator. CISmin as the best ultrasound elastography predictor indicated the lowest AIC and the highest AUC and outperformed alternative indicators significantly in the prediction of delivery before 35weeks of gestation. Unfortunately, CLmin which was commonly used in clinical practice ranked far from all of the cervical elastography parameters and presented the highest AIC and the lowest AUC. A preliminary scoring rule was established and the ability to predict the risk of sPTB in twin pregnancies was improved (Accuracy: 0.896 vs 0.877; AIC: 81.494 vs 91.698; AUC: 0.923 vs 0.906). The cervical elastosonography predictor such as CISmin might be a more useful indicator applied for enhancing the ability in predicting twin pregnancies preterm birth than CL. Furthermore, there would be more benefits for advancing clinical decision-making in actual clinical practice by using cervical elastosonography in the near future.

Dynamic Muscle Stimulation for Pain, Tenderness, and Stiffness on Upper Back Muscles: A Novel Approach and Analysis on Shear-wave Elastography

Abstract Upper back myalgia is a complaint of pain, stiffness, and tightness in the upper back muscles. It is characterized by acute or persistent neck–shoulder pain. We report the case of a 24-year-old male who presented with pain and swelling in the neck and upper back region, along with gradual restriction in cervical range of motion (ROM) for 2 months. The pretreatment assessment revealed severe tightness of the middle fibers of the trapezius and upper fibers of the rhomboid major muscle. Pretreatment elastography revealed high elasticity contrast index (ECI) values of 8.59 and 9.01, respectively, and a red region indicative of increased stiffness of the muscle fibers. The patient was treated with Naqvi’s-Dynamic Electrical Therapy Approach (Naqvi’s DELTA) which is a novel method of using interferential current with a dynamic stimulation probe for 15 min using ultrasound gel on the affected area and examining the patient for the effect of the DELTA on muscle elongation by shear wave elastography which is a unique variation in ultrasound imaging. The pre- and posttreatment findings revealed a significant reduction in stiffness of the muscle fibers, indicated by decreased ECI values of 2.14 and 0.94, respectively, in the blue region. In addition, posttreatment also had an impact on pain reduction and a significant increment in the overall cervical ROM.

High-pressure behavior of 3.65 Å phase: Insights from Raman spectroscopy

Abstract The 3.65 Å phase [MgSi(OH)6] is a hydrous phase that is predicted to be stable in a simplified MgO-SiO2-H2O (MSH) ternary system at pressures exceeding 9 GPa. Along cold subduction zones, it is likely to transport water, bound in its crystalline lattice, into the Earth’s interior. The 3.65 Å phase consists of Mg and Si octahedral sites attached to the hydroxyl group that forms a hydrogen bond and is predicted to undergo pressure-induced symmetrization of the hydrogen bond. Therefore, in this study, we investigate the high-pressure behavior of the 3.65 Å phase using Raman spectroscopy. We have conducted five distinct compressions up to ~60 GPa using two different pressure-transmitting media—alcohol mixture and neon. At ambient conditions, we identified vibrational modes using complementary first-principles simulations based on density functional perturbation theory. Upon compression, we note that the first derivative of the vibrational modes in the lattice region stiffens, i.e., b1lattice &amp;gt; 0. In contrast, the hydroxyl region softens, i.e., b1OH &amp;gt; 0. This is indicative of the strengthening of hydrogen bonding upon compression. We noticed a significant broadening of vibrational modes related to hydroxyl groups that are indicative of proton disorder. However, within the maximum pressures explored in this study, we did not find evidence for pressure-induced symmetrization of the hydrogen bonds. We used the pressure derivative of the vibrational modes to determine the ratio of the bulk moduli and their pressure derivative. We note that the smaller bulk moduli of hydrous phases compared to the major mantle phases are compensated by significantly larger pressure derivatives of the bulk moduli for the hydrous phases. This leads to a significant reduction in the elasticity contrast between hydrous and major mantle phases. Consequently, the detection of the degree of mantle hydration is likely to be challenging at greater depths.

Midtrimester cervical elastography in pregnant women with a history of loop electrosurgical excision procedure (LEEP)

We aimed to compare cervical elastographic parameters based on a previous loop electrosurgical excision procedure (LEEP) and to determine whether they can predict preterm delivery in pregnant women with a history of LEEP. This multicenter prospective case–control study included 71 singleton pregnant women at 14–24 weeks of gestation with a history of LEEP and 1:2 gestational age-matched controls. We performed cervical elastography using E-cervix and compared maternal characteristics, delivery outcomes, cervical length (CL), and elastographic parameters between the two groups. The median mid-trimester CL was significantly shorter in the LEEP group. Most elastographic parameters, including internal os (IOS), external os (EOS), elasticity contrast index (ECI), and hardness ratio (HR), were significantly different in the two groups. In the LEEP group, the sPTD group compared to the term delivery (TD) group showed a higher rate of previous sPTD (50% vs. 1.7%, p < 0.001), higher IOS and ECI (IOS: 0.28 [0.12–0.37] vs. 0.19 [0.10–0.37], p = 0.029; ECI: 3.89 [1.79–4.86] vs. 2.73 [1.48–5.43], p = 0.019), and lower HR (59.97 [43.88–92.43] vs. 79.06 [36.87–95.40], p = 0.028), but there was no significant difference in CL (2.92 [2.16–3.76] vs. 3.13 [1.50–3.16], p = 0.247). In conclusion, we demonstrated that a history of LEEP was associated with a change in cervical strain measured in mid-trimester as well as with CL shortening. We also showed that cervical elastography can be useful in predicting sPTD in pregnant women with previous LEEP.

Performance of Shear Wave Speed Measurements by Using Reverberant Optical Coherence Elastography

Elasticity of biological tissue is important to understand its properties, which could play important role in medical diagnosis and treatment, especially in its early stage of pathology. Optical Coherence Elastography (OCE) has been intensively developed for mapping the elasticity contrast of various biological tissues. OCE techniques based on tracking of shear vibrational wave propagation is one of the most popular techniques. The high speed of shear wave propagation in biological media leads to challenges in both data acquisition and data processing. Recently, the concept of reverberant shear wave fi eld has been applied to OCE, called Rev3D-OCE. In this work, we experimentally investigate the performance of Rev3D-OCE to differentiate gelatin phantoms with a slight difference of elasticity. We verifi ed that Rev3D-OCE can differentiate different shear wave speeds associated with different concentrations of gelatin phantoms, where higher shear wave speed was observed in a higher concentration of the phantom as expected. The average shear wave speed of gelatin with 3 wt% and 4 wt% concentrations were measured as 1.3 ± 0.2 m/s and 1.5 ± 0.1 m/s with about 11% and 14% of errors as compared with that obtained by standard mechanical testing, respectively. In addition, the spatial resolution of Rev3D-OCE as determined from the edge response measurement at the boundary between two gelatins of 3 wt% and 4 wt% concentrations was measured to be 0.3 millimeters.

Use of cervical elastography at 18 to 22 weeks’ gestation in the prediction of spontaneous preterm birth

Accurate identification of the women who will have spontaneous preterm birth continues to be a great challenge. The use of cervical elastography for prediction of preterm birth is promising, but several limitations exist. Newer cervical elastography technology has been developed that may prove useful in evaluation of risk of preterm birth. This study aimed to develop standard cervical elastography nomograms for singleton pregnancies at 18 to 22 weeks' gestation using the E-Cervix ultrasound application, assess intraobserver reliability of the E-Cervix elastography parameters, and determine whether these cervical elastography measurements can be used in the prediction of spontaneous preterm birth. This was a prospective cohort study of pregnant women undergoing cervical length screening assessment via transvaginal ultrasound examination at 18 to 22 weeks' gestation. A semiautomatic, cervical elastography application (E-Cervix) was used during the transvaginal examination to calculate 5 quantitative parameters (internal os stiffness, external os stiffness, internal -to -external os stiffness ratio, hardness ratio, and elasticity contrast index) and create a standard nomogram for each one of them. The intraobserver reliability was calculated using Shrout-Fleiss reliability. Cervical elastography parameters were compared between those who delivered preterm (<37 weeks) spontaneously and those who delivered full term. A multivariable logistic regression model was performed to determine the ability of the cervical elastography parameters to predict spontaneous preterm birth. A total of 742 women were included, of which 49 (6.6%) had a spontaneous preterm delivery. A standard nomogram was created for each of the cervical elastography parameters from those who had a full-term birth in the index pregnancy (n=693). Intraobserver reliability was good or excellent (intraclass correlation, 0.757-0.887) for each of the cervical elastography parameters except external os stiffness which was poor (intraclass correlation, 0.441). In univariate analysis, none of the cervical elastography parameters were associated with a statistically significant increased risk of spontaneous preterm birth. In a multivariable model adjusting for history of preterm birth, gravidity, ethnicity, cervical cerclage, and vaginal progesterone use, increasing elasticity contrast index was significantly associated with an increased risk of spontaneous preterm birth (odds ratio, 1.15; 95% confidence interval, 1.02-1.30; P=.02). Cervical elastography parameters are reliably measured and are stable across 18 to 22 weeks' gestation. Based on our findings, the elasticity contrast index was associated with an increased risk of spontaneous preterm birth and may be a useful parameter for future research.

The Feasibility of Cervical Elastography in Predicting Preterm Delivery in Singleton Pregnancy with Short Cervix Following Progesterone Treatment.

Previous studies demonstrated an association between cervical strain and risk of spontaneous preterm delivery (sPTD). The present study aimed to assess the efficacy of elastography in predicting sPTD at <32 weeks of gestation in women with singleton pregnancies receiving progesterone for short cervix (≤2.5 cm) diagnosed between 16 and 28 weeks of gestation Among 115 participants eligible for analysis, nine had sPTD at <32 weeks. Preprogesterone (PP0) mean internal os strain (IOS), elasticity contrast index (ECI), hardness ratio (HR), one-week postprogesterone (PP1) IOS, mean external os strain (EOS), ECI, and HR were significantly different between groups. Higher PP0 IOS, PP1 IOS, and PP1 EOS were associated with a 2.92, 4.39 and 3.65-fold increase in the risk of sPTD at <32 weeks, respectively (adjusted for cervical length (CL) at diagnosis; p = 0.04, 0.012 and 0.026, respectively). A combination of CL at diagnosis, PP0 IOS and PP1 EOS showed a significantly higher area under the receiver operating characteristic curve (0.858) than that of CL alone (p = 0.041). In women with singleton pregnancies receiving progesterone for short cervix, cervical elastography performed before and one week after progesterone treatment may be useful in predicting sPTD at <32 weeks of gestation.

Uterine Cervical Change at Term Examined Using Ultrasound Elastography: A Longitudinal Study.

The aim of the study was to investigate if there are changes in elastographic parameters in the cervix at term around the time of delivery and if there are differences in the parameters between women with spontaneous labor and those without labor (labor induction). Nulliparous women at 36 weeks of gestation eligible for vaginal delivery were enrolled. Cervical elastography was performed and cervical length were measured using the E-CervixTM system (WS80A Ultrasound System, Samsung Medison, Seoul, Korea) at each weekly antenatal visit until admission for spontaneous labor or labor induction. E-Cervix parameters of interest included elasticity contrast index (ECI), internal os strain mean level (IOS), external os strain mean level (EOS), IOS/EOS strain mean ratio, strain mean level, and hardness ratio. Regression analysis was performed using days from elastographic measurement at each visit to admission for delivery and the presence or absence of labor against cervical length, and each E-Cervix parameter fitted to a linear model for longitudinal data measured repeatedly. A total of 96 women were included in the analysis, (spontaneous labor, n = 39; labor induction, n = 57). Baseline characteristics were not different between the two groups except for cesarean delivery rate. Cervical length decreased with advancing gestation and was different between the two groups. Most elastographic parameters including ECI, IOS, EOS, strain mean, and hardness ratio were significantly different between the two groups. In addition, ECI, IOS, and strain mean values significantly increased with advancing gestation. Our longitudinal study using ultrasound elastography indicated that E-cervix parameters tended to change linearly at term near the time of admission for delivery and that there were differences in E-Cervix parameters according to the presence or absence of labor.

Novel 2D Dynamic Elasticity Maps for Inspection of Anisotropic Properties in Fused Deposition Modeling Objects

In this study, a novel ultrasonic non-destructive and non-invasive elastography method was introduced and demonstrated to evaluate the mechanical properties of fused deposition modeling 3D printed objects using two-dimensional dynamical elasticity mapping. Based on the recently investigated dynamic bulk modulus and effective density imaging technique, an angle-dependent dynamic shear modulus measurement was performed to extract the dynamic Young’s modulus distribution of the FDM structures. The elastographic image analysis demonstrated the presence of anisotropic dynamic shear modulus and dynamic Young’s modulus existing in the fused deposition modeling 3D printed objects. The non-destructive method also differentiated samples with high contrast property zones from that of low contrast property regions. The angle-dependent elasticity contrast behavior from the ultrasonic method was compared with conventional and static tensile tests characterization. A good correlation between the nondestructive technique and the tensile test measurements was observed.

Anisotropic disclination cores in nematic liquid crystals modeled by a self-consistent molecular field theory.

Disclination configurations of a nematic liquid crystal are studied within a self-consistent molecular field theory. The theory is based on a tensor order parameter, and can accommodate anisotropic elastic energies without the known divergences in the Landau-de Gennes formulation. Our results agree with the asymptotic results of Dzyaloshinskii for the Frank-Oseen energy far from the defect core, but reveal biaxial order at intermediate distances from the core, crossing over to uniaxial but axisymmetric configurations as the core is approached. The elastic terms considered in our energy allow for the separate control of surface tension, anchoring, and elasticity contrast, and are used to analyze recent results for lyotropic chromonic liquid crystals. The latter display unusually large defect cores (on the order of tens of microns) which can be used for a quantitative comparison with the theory. Both ±1/2 disclination configurations are well reproduced by our calculations. Elastic anisotropy is also shown to lead to qualitative changes in the disclination polarization, a quantity that is proportional to the active stress in models of active matter.

Reliability of strain elastography using in vivo compression in the assessment of the uterine cervix during pregnancy.

Objective To determine the reproducibility of the mean strain value in various cervical areas and new elastographic parameters for measuring cervical stiffness evaluated by strain elastography using in vivo compression generated by internal organ movement. Methods A prospective observational study (140 singleton pregnant women; 15-33 weeks of gestation) was performed at two tertiary centers. Cervical strain was evaluated using E-cervix™ elastography. The mean strain levels of various cervical areas [internal os (IOS), external os (EOS) and endocervical area] and several new parameters [i.e. the ratio of the strain level of IOS and EOS, elasticity contrast index (ECI), and hardness ratio] were assessed twice by two independent examiners. The inter-observer and intra-observer variances were calculated using the intraclass correlation coefficient (ICC) with a 95% confidence interval (CI). Bland-Altman (B-A) analysis was also performed. Results The median gestational age was 24.0 weeks, and the mean cervical length (CL) was 3.8 cm. The intra-observer and inter-observer ICCs of the mean strain levels of the specified cervical area and new elastographic parameters were statistically significant (P < 0.001, all); the intra-observer ICC was 0.639-0.725, and the inter-observer ICC was 0.538-0.718. Conclusion The reproducibility of elastographic parameter measurements using in vivo compression is improvable.

Correlation between cervical elastography parameters and time of the first stage of labor in late pregnancy by transvaginal ultrasound

Objective To investigate the correlations between the labor process and the elastography parameters, and to explore the correlations among the elastography parameters. Methods A total of 48 pregnant women in the late periods of pregnancy in Beijing Hospital from November 10, 2018 to January 30, 2019 were recruited prospectively. Elastography was performed to measure several elastographic parameters including the cervical length (CL), elasticity contrast index (ECI), hardness ratio (HR), internal orifice uterus(IOS) and external orifice uterus(EOS). They were followed up to delivery, and were divided into normal group and prolonged group according to the time duration of the first stage of labor. The correlation between the parameters and the time duration of the first stage of labor, as well as the relationships among the parameters were evaluated. Results Among the 48 pregnant women, 35 cases were delivered by the vagina, 13 by cesarean section, 4 of whom were due to the prolongation of the first stage of labor and the other 9 cases for other reasons. The values of the CL and HR in normal group were significantly lower than that in prolonged group (P=0.004, 0.02). The ECI in the normal group was significantly higher than that in the prolonged group (P=0.046). Both the IOS and EOS in the normal group were higher than those in prolonged group without no significant difference(P>0.05). For the 35 women who underwent cervical elasticity assessment before labor and finally delivered vaginally, the duration of the first stage of labor was negatively correlated with cervical ECI (r=-0.415, P 0.05). Conclusions The ECI of cervical tissue measured by cervical elastography can be used to semi-quantitatively evaluate the maturity of the cervix, it has potential value in predicting the labor duration and guiding clinical decision-making. Key words: Ultrasonography, transvaginal; Elastography; Time of the first labor; Late pregnancy