Imaging analysis of cervical elastography for prediction of successful induction of labor at term

Reliability of the sonographic evaluation for cervical length and elastography with pelvic parameters in term pregnancy by experienced operators with varying levels of experience

OBJECTIVE

To assess the reliability of sonographic measurements of six cervical and pelvic parameters by three sonographers with varying levels of experience.

METHODS

A cross-sectional study was conducted in pregnant women with a gestational age of ≥39 weeks. Each pregnant woman was examined by two sonographers with different levels of experience. Six parameters were measured: cervical length (CL), cervical strain elastography (extrinsic type), posterior cervical angle (PCA), fetal head-to-perineum distance (FHPD), fetal head-to-pubic symphysis distance (FHSD), and angle of progression (AOP). Intra- and interobserver reliabilities were assessed using the intraclass correlation coefficient with a 95% confidence interval. Pearson pairwise correlation coefficients were used to analyze the correlation between the parameter values.

RESULTS

In all, 66 pregnant women were enrolled in this study. We found excellent intraobserver reliability for measurements of CL, PCA, FHPD, FHSD, and AOP and good-to-excellent intraobserver reliability for cervical strain values in the cross-sectional view of the endocervix in the internal os area and cross-sectional view of the entire cervix in the internal os area. Interobserver reliability was excellent for all pelvic parameters, except for the FHPD. Strain values were moderate to excellent in the area of the internal os. A significant negative correlation between CL and strain values at the internal os was observed.

CONCLUSIONS

Pelvic parameters, except for FHPD, have excellent intra- and interobserver reliabilities. The high reproducibility of CL and cervical strain elastography at the internal os level, with a negative correlation between these two parameters, may play an important role in predicting successful induction of labor.

Reliability and Reproducibility of Analyzing 3D Transperineal Ultrasound Volumes Obtained in the First Phase of Labor - A Pilot Study

PURPOSE

The aim of this study was to investigate the reliability and reproducibility of transperineal ultrasound (TPUS) in the initial phase of labor. As TPUS is a common method, it could supplement vaginal palpation and even replace it in certain situations. In addition, we used a 4-dimensional method for the assessment of cervical effacement.

MATERIALS AND METHODS

54 women in labor were included and underwent TPUS. The resulting images from the acquired 4D volumes were evaluated after the examination for the first time and a second time after 21 days. The measured values were cervical length, dilatation and effacement, the angle of progression (AoP), and head-perineum distance.

RESULTS

54 patients were examined. TPUS images were unable to be evaluated in 12 patients because of cervical dilatation of more than 5 cm or poor image quality. Thus, 42 measurements were included. The concordance correlation coefficients according to Lin are satisfactory overall, with one exception for cervical effacement. The accuracy component of cervical length (CCCLin: 0.93; accuracy: 1.00), dilatation (CCCLin: 0.93; accuracy: 1.00), and AoP (CCCLin: 0.87; accuracy: 1.00) is excellent and still high for the head-perineum distance (CCCLin: 0.89; accuracy: 0.96) and cervical effacement (CCCLin: 0.77; accuracy: 0.97).

CONCLUSION

TPUS is a valuable noninvasive tool with good diagnostic accuracy for the AoP, cervical length, and dilatation. Our study provides support for the use of TPUS to complement a vaginal examination. It should not replace a digital examination but should serve as a suitable alternative method for monitoring labor progression in the future.

Development and validation of a nomogram to predict spontaneous preterm birth in singleton gestation with short cervix and no history of spontaneous preterm birth

Background

Spontaneous preterm birth (sPTB) stands as a leading cause of neonatal mortality. Consequently, preventing sPTB has emerged as a paramount concern in healthcare. Therefore, our study aimed to develop a nomogram, encompassing patient characteristics and cervical elastography, to predict sPTB in singleton pregnancies. Specifically, we targeted those with a short cervix length (CL), no history of sPTB, and who were receiving vaginal progesterone therapy.

Methods

A total of 568 patients were included in this study. Data from 392 patients, collected between January 2016 and October 2019, constituted the training cohort. Meanwhile, records from 176 patients, spanning November 2019 to January 2022, formed the validation cohort. Following the univariate logistic regression analysis, variables exhibiting a P-value less than 0.05 were integrated into a multivariable logistic regression analysis. The primary objective of this subsequent analysis was to identify the independent predictors linked to sPTB in the training cohort. Next, we formulated a nomogram utilizing the identified independent predictors. This tool was designed to estimate the likelihood of sPTB in singleton pregnancies, particularly those with a short CL, devoid of any sPTB history, and undergoing vaginal progesterone therapy. The C-index, Hosmer-Lemeshow (HL) test, calibration curves, decision curve analysis (DCA), and receiver operating characteristic (ROC) were used to validate the performance of the nomogram.

Results

Upon finalizing the univariate analysis, we progressed to a multivariable analysis, integrating 8 variables with P < 0.05 from the univariate analysis. The multivariable analysis identified 7 independent risk factors: maternal age (OR = 1.072; P < 0.001), cervical length (OR = 0.854; P < 0.001), uterine curettage (OR = 7.208; P < 0.001), GDM (OR = 3.570; P = 0.006), HDP (OR = 4.661; P = 0.003), C-reactive protein (OR = 1.138; P < 0.001), and strain of AI (OR = 7.985; P < 0.001). The nomogram, tailored for sPTB prediction, was grounded on these 7 independent predictors. In predicting sPTB, the C-indices manifested as 0.873 (95% CI, 0.827-0.918) for the training cohort and 0.916 (95%CI, 0.870-0.962) for the validation cohorts, underscoring a good discrimination of the model. Additionally, the ROC curves served to evaluate the discrimination of nomogram model across both cohorts. Calibration curves were delineated, revealing no statistically significant differences in both the training (χ2 = 5.355; P = 0.719) and validation (χ2 = 2.708; P = 0.951) cohorts as evidenced by the HL tests. Furthermore, the DCA underscored the model's excellence as a predictive tool for sPTB.

Conclusions

By amalgamating patient characteristics and cervical elastography data from the second trimester, the nomogram emerged as a visually intuitive and dependable tool for predicting sPTB. Its relevance was particularly pronounced for singleton pregnancies characterized by a short CL, an absence of prior sPTB incidents, and those receiving vaginal progesterone therapy.

Diagnostic accuracy of pre-induction cervical elastography, volume, length, and uterocervical angle for the prediction of successful induction of labor with dinoprostone

PURPOSE

The study's aim is to define among a group of ultrasonographic cervical measurements a candidate parameter predictive of successful of induction of labor in term pregnancies with unfavorable cervix.

METHODS

This prospective observational study included 141 pregnant women at term with an unfavorable cervix (Bishop score ≤ 6). All patients underwent clinical and ultrasonographic cervical evaluation before dinoprostone induction. Pre-induction cervical assessments included the Bishop score, cervical length, cervical volume, uterocervical angle, and cervical elastographic parameters. Vaginal delivery (VD) was accepted as successful dinoprostone induction. Multivariate logistic regression was conducted to identify the potential risk factors significantly associated with CS while controlling for possible confounding variables.

RESULTS

The vaginal delivery rate was 74% (n = 93) and the cesarean section (CS) rate was 26% (n = 32). Sixteen patients who had a cesarean section due to fetal distress before the active phase of labor were excluded from the study. The mean induction-to-delivery interval was 1176.1 ± 352 (540-2150) for VD and 1359.4 ± 318.4 (780-2020) for CS (p = 0.01). Bishop score was lower in women with cesarean section (p = 0.002). When both groups were compared in terms of delivery type, no difference was found between cervical elastography values, cervical volume, cervical length, and uterocervical angle measurements. Multivariable logistic regression model failed to show significant differences between cervical elastography values, cervical volume, cervical length, and uterocervical angle measurements.

CONCLUSION

Cervical length, cervical elastography, cervical volume, and uterocervical angle measurements did not provide a clinically useful prediction of outcomes following labor induction in our study group with unfavorable cervix. Cervical length measurements significantly predicted the time interval from induction to delivery.

Diagnostic accuracy of cervical elastography for predicting preterm delivery: Systematic review and meta-analysis

OBJECTIVE

Cervical elastography has been used in pregnant women to diagnose preterm births. However, there is a variability in the measured elasticity parameters and imaging mode used. We evaluated the precision of cervical elastography in identifying preterm births.

METHODS

Extensive and methodical searches were made in the databases such as Scopus, Embase, Cochrane Library, PubMed Central, Medline, ScienceDirect, and Google Scholar from the inception until November 2022, for studies that report diagnostic accuracy of cervical elastography for preterm deliveries in antenatal women.

RESULTS

The pooled sensitivity and specificity value of cervical elastography for preterm deliveries were 82% (95%CI: 73%-89%) and 77% (95%CI: 64%-86%), respectively with area under curve (AUC) of 0.87 (95%CI: 0.72-0.95). The diagnostic odds ratio (DOR) was 15 (95%CI: 8-28), positive likelihood ratio (LRP) was 3.5 (95%CI: 2.3-5.5) and negative likelihood ratio LRN was 0.23 (0.16-0.34). Pooled sensitivity and specificity of shear wave elastography was 88% and 71%, respectively. Pooled sensitivity and specificity of strain elastography was 80% and 79%, respectively. Heterogeneity was significant, as indicated by chi-square test and an I2 statistic of over 75.

CONCLUSIONS

Cervical elastography can be used for predicting preterm deliveries with moderate to high level of accuracy.

Predictive Value of Cervical Shear Wave Elastography in the Induction of Labor in Late-Term Pregnancy Nulliparous Women: Preliminary Results

The prediction of induction of labor continues to be a paradigm nowadays. Bishop Score is the traditional widely spread method but with a low reliability. Ultrasound cervical assessment has been proposed as an instrument of measurement. Shear wave elastography (SWE) should be a promising tool in the prediction of the success of labor induction in nulliparous late-term pregnancies. Ninety-two women with nulliparous late-term pregnancies who were going to be induced were included in the study. A shear wave measurement of the cervix divided into six regions (inner, middle and outer in both cervical lips), cervical length and fetal biometry was performed by blinded investigators prior to routine hand cervical assessment (Bishop Score (BS)) and induction of labor. The primary outcome was success of induction. Sixty-three women achieved labor. Nine women did not, and they underwent a cesarean section due to failure to induce labor. SWE was significantly higher in the inner part of the posterior cervix (p < 0.0001). SWE showed an area under the curve (AUC): 0.809 (0.677-0.941) in the inner posterior part. For CL, AUC was 0.816 (0.692-0.984). BS AUC was 0.467 (0.283-0.651). The ICC of inter-observer reproducibility was ≥0.83 in each region of interest (ROI). The cervix elastic gradient seems to be confirmed. The inner part of the posterior cervical lip is the most reliable region to predict induction of labor results in SWE terms. In addition, cervical length seems to be one of the most important procedures in the prediction of induction. Both methods combined could replace the Bishop Score.

Prediction model for successful induction of labor by cervical strain elastography diagnosed at late-term pregnancy in nulliparous women: a prospective cohort study

BACKGROUND

The use of cervical strain elastography for nulliparous women during late-term pregnancy remains unclear. This study assesses the predictive value of late-term cervical strain elastography for successful induction of labor (IOL) in nulliparous women.

METHODS

This single-centered, prospective study included 86 patients undergoing IOL between January 2020 and March 2022. Univariate and multivariate analyses were conducted to identify predictive factors for successful IOL. The predictive values were assessed using the area under receiver operating characteristic (ROC) curves.

RESULTS

IOL was successful in 58 patients. The hardness ratio and cervical length were significantly associated with successful late-term IOL in nulliparous women. The predictive value of the combination of hardness ratio and cervical length was higher than that of cervical length alone.

CONCLUSIONS

The hardness ratio and cervical length assessed by cervical strain elastography during late-term pregnancy are predictors of the success of IOL in nulliparous women. The predictive value of the combination of hardness ratio and cervical length was higher than that of cervical length alone.

Association between the cervical sliding sign and successful induction of labor in women with an unfavorable cervix: A prospective observational study

OBJECTIVES

To evaluate the role of the cervical sliding sign (CSS) in the prediction of the outcome of induction of labor (IOL).

STUDY DESIGN

Two-center prospective observational cohort study involving a non-consecutive series of uncomplicated singleton term pregnancies, planned for IOL, with a fetus in cephalic presentation and unfavorable cervix as defined by a Bishop score ≤ 6. The Bishop score was evaluated by transvaginal digital examination and the cervical length and CSS by transvaginal ultrasound. The presence of CSS was defined as the sliding of the anterior cervical lip on the posterior one under gentle pressure of the transvaginal probe. The primary outcome of the study was successful vaginal delivery within 24 h. The secondary outcome was the induction-to-active-labor time. The interobserver agreement for the CSS was also evaluated.

RESULTS

Over a period of 12 months, 179 women were included. The CSS was found in 86 (48.0 %) patients and was associated with an increased likelihood of vaginal delivery within 24 h (60/86 or 69.8 % vs 27/93 or 29.0 %, P < 0.001) and a shorter induction-to-active-labor time (954 ± 618 min vs 1416 ± 660 min, P < 0.001). Multivariable regression analysis showed that the CSS was an independent predictor of vaginal delivery within 24 h (aOR 5.37, 95 % CI 2.26-12.75) and shorter induction-to-active-labor time interval (HR 1.81, 95 % CI 1.19-2.74). The interobserver variability based on intraclass correlation coefficient for the CSS was excellent (ICC = 0.90).

CONCLUSION

In women undergoing IOL with an unfavorable cervix, the CSS is associated with a higher frequency of vaginal delivery within 24 h and a shorter induction-to-active-labor time.

Cervical and Lower Uterine Parameter Ultrasound and Elastographic Parameters for the Prediction of a Successful Induction of Labor

PURPOSE

 The prediction of successful induction of labor (IOL) has been the subject of a series of studies. The predictive role of cervical sonographic and elastographic parameters has been controversially discussed. Lower uterine segment (LUS) thickness and strain values have not been discussed yet in this regard.

MATERIALS AND METHODS

 A prospective cohort study was performed to examine the predictive power of Bishop score parameters, sonographic cervical length (CL), cervical funneling, cervical strain values, LUS thickness and its strain values regarding successful IOL within 24 hours and intervals to onset of labor, ROM and delivery of the fetus. A p-value of < 0.05 was considered statistically significant.

RESULTS

 135 patients were examined. A cervical length of 25 mm, the presence of cervical funneling and digital shorter cervix was significant for the prediction of successful induction of labor (IOL) within 24 hours. There was weak correlation between the functional CL and the onset of labor (r² = 0.10) and ROM (r² = 0.13). There was also a weak correlation between the cervical funnel width and the time interval to the onset of labor (r² = 0.25), ROM (r² = 0.23) and delivery of the fetus (r² = 0.22). Cervical elastography, LUS thickness and strain values were not significant for the prediction of a successful IOL.

CONCLUSION

 We were able to show that cervical structural changes at the level of the internal os, i. e., shortening through funneling, may be the determining factor for successful IOL.

Advancements in the Application of Ultrasound Elastography in the Cervix

Ultrasound elastography is a modern imaging technique that has developed rapidly in recent years. It enables objective measurement of tissue stiffness, a physical property intuitive to the human sense of touch. This novel technology has become a hotspot and plays a major role in scientific research and academic practice. Presently, ultrasound elastography has been used in the identification of benign and malignant tumors in superficial organs, such as breast and thyroid, providing clinically accurate diagnosis and treatment. The method has also been widely used for the liver, kidney, prostate, lymph nodes, blood vessels, skin and muscle system. In the application of cervical lesions, ultrasound elastography can distinguish normal cervix from abnormal cervix and differentiate benign from malignant lesions. It can significantly improve the diagnostic specificity for cervical cancer and is also useful for assessing infiltration depth and stage of cervical cancer, as well as predicting chemoradiotherapy treatment response. For cervical evaluation during pregnancy, ultrasound elastography is useful for assessing cervical softening and predicting premature delivery and outcome of induced labor. This article reviews the principles of ultrasound elastography as well as the current status and limitations in its application for cervical lesions and the cervix during pregnancy.

Predictive value of cervical length by ultrasound and cervical strain elastography in labor induction at term

OBJECTIVE

This study aimed to examine whether addition of cervical elastographic parameters measured by ElastoScan for the cervix (E-cervix) improves the predictive value of cervical length (CL) in induction of labor at term by dinoprostone.

METHODS

We conducted a prospective, observational study between January 2020 and June 2020 in term primiparous women (n = 73) who were scheduled for labor induction by a 10-mg dinoprostone vaginal insert. The time intervals from the start of labor induction to regular uterine contractions and to vaginal delivery were calculated as the primary outcomes. We divided subjects into two groups using a threshold of 24 hours. Ultrasound measurements were compared between the two groups and the area under the curve (AUC) of the prediction model was calculated.

RESULTS

Women who delivered vaginally within 24 hours had a shorter CL and softer cervix than those who delivered after 24 hours. The combination of CL and elastographic parameters increased the AUC to 0.672 compared with CL alone (AUC = 0.637).

CONCLUSIONS

Measurement by E-cervix is relatively reproducible. Addition of cervical strain elastography slightly improves the predictive performance of CL in vaginal delivery within 24 hours. This technique is a promising ancillary tool for use with ultrasound.

The Uterocervical Angle Combined with Bishop Score as a Predictor for Successful Induction of Labor in Term Vaginal Delivery

The objective of this study was to determine the value of uterocervical angle (UCA) in predicting successful induction of labor (IOL) in singleton pregnant women compared to the Bishop score and cervical length (CL). A total of 205 normal term, singleton labor-induction cases were analyzed. Successful IOL was defined as the onset of active labor of induction. A comparative analysis was performed to evaluate the effectiveness of UCA, Bishop score, and CL in predicting IOL. Compared to the non-successful IOL group, the women in the successful IOL group had significantly wider UCA (p = 0.012) and higher Bishop score (p = 0.001); however, the CL was not significantly different (p = 0.130). UCA alone did not perform better than the Bishop score when predicting successful IOL. However, UCA combined with the Bishop score showed higher performance in predicting IOL (combined UCA > 108.4° and favorable Bishop score as sensitivity of 44.6%, specificity of 96.0%, PPV of 96.2%, and NPV of 43.6; combined UCA > 108.4° or favorable Bishop score as sensitivity of 85.7%, specificity of 50.0%, PPV of 78.7%, and NPV of 61.9). In conclusion, UCA combined with Bishop score may be an effective sonographic method for predicting successful IOL.

Vaginal elasticity is significantly decreased in vaginal atrophy: a strain elastography study

OBJECTIVES

Strain elastography is a novel method to assess the elasticity of tissues. We aimed to evaluate the value of vaginal strain elastography in women with vulvovaginal atrophy (VVA).

METHODS

Women with or without VVA were enrolled in this prospective study. Participants underwent vaginal cytology and vaginal wall elastography. Vaginal Health Index (VHI) was calculated. Based on Vaginal Maturation Value (VMV), participants were divided into atrophic and nonatrophic groups. Elastography parameters of the vaginal walls were measured in nine regions of interest (ROI). Elastography Index (EI) was defined by the average color score of nine ROIs. Groups were compared with unpaired t test or Mann-Whitney U test. Pearson correlation was used to determine the strength of association between EI and selected parameters. Multiple regression was used to evaluate the association between EI and age, VMV, and vaginal atrophy.

RESULTS

Ten women were diagnosed with VVA, and twenty had no cytological signs of vaginal atrophy (age-range 38-79 y). VHI score was significantly lower in the atrophic group (mean ± SD, 9.4 ± 2.011 vs 16.6 ± 4.22, P < 0.0001). In the atrophic group, EI was significantly lower than in nonatrophic group (mean ± SD, 20 ± 21 vs 47 ± 4, P < 0.01). We found a strong negative correlation between EI and vaginal atrophy (r =  -0.706, P < 0.0001; 95% CI: 0.8501 to -0.4639). In the multiple regression model, only atrophy remained statistically significant for the prediction of EI (P = 0.004).

CONCLUSIONS

Vaginal elasticity is significantly decreased in women with vaginal atrophy, measured by EI. Our results suggest that strain elastography might be useful in the diagnosis of vaginal atrophy.

Spectroscopic photoacoustic imaging of cervical tissue composition in excised human samples

Objective

Cervical remodeling is an important component in determining the pathway of parturition; therefore, assessing changes in cervical tissue composition may provide information about the cervix’s status beyond the measurement of cervical length. Photoacoustic imaging is a non-invasive ultrasound-based technology that captures acoustic signals emitted by tissue components in response to laser pulses. This optical information allows for the determination of the collagen-to-water ratio (CWR). The purpose of this study was to compare the CWR evaluated by using spectroscopic photoacoustic (sPA) imaging in cervical samples obtained from pregnant and non-pregnant women.

Methods

This cross-sectional study comprised cervical biopsies obtained at the time of hysterectomy (n = 8) and at the scheduled cesarean delivery in pregnant women at term who were not in labor (n = 8). The cervical CWR was analyzed using a fiber-optic light-delivery system integrated to an ultrasound probe. The photoacoustic signals were acquired within the range of wavelengths that cover the peak absorption of collagen and water. Differences in the CWR between cervical samples from pregnant and non-pregnant women were analyzed. Hematoxylin and eosin and Sirius Red stains were used to compare the collagen content of cervical samples in these two groups.

Results

Eight cervix samples were obtained after hysterectomy, four from women ≤41 years of age and four from women ≥43 years of age; all cervical samples (n = 8) from pregnant women were obtained after 37 weeks of gestation at the time of cesarean section. The average CWR in cervical tissue samples from pregnant women was 18.7% (SD 7.5%), while in samples from non-pregnant women, it was 55.0% (SD 20.3%). There was a significantly higher CWR in the non-pregnant group compared to the pregnant group with a p-value <0.001. A subgroup analysis that compared the CWR in cervical samples from pregnant women and non-pregnant women ≤41 years of age (mean 46.3%, SD 23.1%) also showed a significantly higher CWR (p <0.01). Lower collagen content in the pregnancy group was confirmed by histological analysis, which revealed the loss of tissue composition, increased water content, and collagen degradation.

Conclusion

The proposed bimodal ultrasound and sPA imaging system can provide information on the biochemical composition of cervical tissue in pregnant and non-pregnant women. Photoacoustic imaging showed a higher collagen content in cervical samples from non-pregnant women as compared to those from pregnant women, which matched with the histological analysis. This novel imaging method envisions a new potential for a sensitive diagnostic tool in the evaluation of cervical tissue composition.

Cervical elastography strain ratio and strain pattern for the prediction of a successful induction of labour

OBJECTIVES

The aim of this study was to introduce cervical strain elastography to objectively assess the cervical tissue transformation process during induction of labour (IOL) and to evaluate the potential of cervical elastography as a predictor of successful IOL.

METHODS

A total of 41 patients with full-term pregnancies elected for an IOL were included. Vaginal ultrasound with measurement of cervical length and elastography and assessment of the Bishop Score were performed before and 3 h after IOL. The measured parameters were correlated to the outcome of IOL and the time until delivery.

RESULTS

We observed an association between the strain pattern and the value of the strain ratio 3 h after IOL and a successful IOL (p=0.0343 and p=0.0342, respectively) which can be well demonstrated by the results after 48 h. In our study population the cervical length and the Bishop Score did not prove to be relevant parameters for the prediction of a successful IOL.

CONCLUSIONS

We demonstrated for the first time that the cervical elastography pattern after the first prostaglandine application can help predict the outcome of IOL.

Relationship between cervical elastography and spontaneous onset of labor

Cervical elastography might be an objective method for evaluating cervical ripening during pregnancy, but its usefulness has not been fully investigated. We examined the significance of cervical elastography in the last trimester of pregnancy. Cervical elastography was performed at weekly checkups after 36 weeks of gestation in 238 cases delivered at our hospital from 2017 to 2018. The correlation with the onset time of natural labor, which is an index for judging maternal delivery preparation status, was examined. A total of 765 examinations were conducted, and cervical stiffness determined by cervical elastography was positively correlated with the Bishop score (r = 0.46, p < 0.0001). When examined separately for each week, only the examinations performed at 39 weeks were associated with the onset of spontaneous labor up to 7 days later (p = 0.0004). Furthermore, when stratified and analyzed by the Bishop score at 39 weeks of gestation, cervical elastography was associated with the occurrence of spontaneous labor pain for up to seven days in the groups with Bishop scores of 3–5 and 6–8 (p = 0.0007 and p = 0.03, respectively). In conclusion, cervical elastography at 39 weeks of pregnancy is useful for judging the delivery time.

USEFULNESS OF TRANSPERINEAL VIRTUAL TOUCH QUANTIFICATION IN THE CERVIX FOR PREDICTING OUTCOME OF LABOR INDUCTION

This study aimed to explore the feasibility of transperineal virtual touch tissue quantification (VTQ) for predicting the outcome of labor induction. A total of 80 nulliparous pregnant women were included. Before labor induction, cervical length was measured by B-mode sonography, cervical stiffness was measured by VTQ, and Bishop score was assessed by vaginal examination. Subsequently, labor was induced using standard oxytocin infusion in all patients. Delivery within 24 hours after labor induction was classified as spontaneous delivery; otherwise, cesarean delivery was performed. Out of 80 participants, 48 (60%) delivered vaginally and 32 (40%) underwent cesarean delivery. The cervical length was significantly longer and the shear wave velocity (SWV) was greater in the cesarean delivery group than in the vaginal delivery group (p = 0.004 and p < 0.000, respectively). Logistic regression analysis indicated that only the mean SWV had independent predictive value for the outcome of labor induction (p = 0.011). The best diagnostic cut-off point of the mean SWV was 1.23 m/s, with a sensitivity of 93.8% and a specificity of 89.6%. Transperineal VTQ technique could predict the outcome of labor induction using oxytocin.

ACR Appropriateness Criteria® Assessment of Gravid Cervix

Preterm birth remains the leading cause of perinatal morbidity and mortality. Although the greatest risk factor for preterm birth is a history of prior preterm birth, a short cervical length (≤25 mm) before 24 weeks' gestational age is also associated with increased risk of spontaneous preterm delivery. As such, cervical length assessment has become of particular interest in predicting those patients at risk for preterm birth. Other clinical scenarios (eg, preterm labor, induction of labor, and active labor) may arise, in which assessment of the cervix may be of interest. Ultrasound is the mainstay imaging modality for assessing the gravid cervix, with transvaginal ultrasound recommended in patients at high risk for preterm birth or suspected preterm labor. Transperineal ultrasound is an alternate approach in those cases where transvaginal ultrasound in contraindicated. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Evaluation of Cervical Elastography for Prediction of Spontaneous Preterm Birth in Low-Risk Women: A Prospective Study

OBJECTIVES

The aim of this study was to determine whether cervical elastographic parameters in addition to cervical length (CL) during the 3 trimesters of pregnancy would be predictive of spontaneous preterm birth (sPTB) among low-risk women.

METHODS

This work was a prospective nested case-control study evaluating cervical elastographic parameters and CL in low-risk women during the 3 trimesters of pregnancy. A binary logistic regression analysis was used to calculate significant covariates for prediction of sPTB. The area under the curve of the prediction model was calculated by using a receiver operating characteristic curve.

RESULTS

There were 286 women (26 cases and 260 controls) included in the analysis. The parameters of cervical elasticity became softened and heterogeneous during the 3 trimesters of pregnancy in both women with and without sPTB. The differences in the mean strain value at the internal os of the cervix (IOS), ratio (strain ratio of the internal os to the external os) during the second trimester and the IOS during the third trimester between the groups had statistical significance (P < .01; P = .01; P < .01, respectively). The CL had no association with sPTB during the 3 trimesters. The IOS during the second trimester was a better predictor of sPTB, with an area under the curve of 0.730, and sensitivity was 72.73%.

CONCLUSIONS

We observed multiple elastographic parameters and demonstrated the physiologic changes in the cervix during the 3 trimesters of pregnancy. Furthermore, we found that the IOS during the second trimester can be helpful in predicting sPTB. However, the CL had no association with sPTB during the 3 trimesters of pregnancy.

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.

Quantitative elastography of cervical stiffness during the three trimesters of pregnancy with a semiautomatic measurement program: A longitudinal prospective pilot study

AIM

To assess the reproducibility of a semiautomatic quantification tool for cervical stiffness and evaluate the normal changes in cervical elasticity during the three trimesters of pregnancy.

METHODS

This longitudinal prospective pilot study evaluated cervical elasticity during the three trimesters of pregnancy (11-14, 20-24 and 28-32 weeks) in women with singleton pregnancies. Women with a history of conization, cerclage, cervical Naboth cysts (diameter > 10 mm), cervical tumors, or uterine malformation were excluded. A semiautomatic tool was used to evaluate the stiffness of the whole cervix and the internal and external cervical os with multiple quantitative elasticity parameters and the cervical length (CL) on the sagittal view via transvaginal elastography. Intraclass correlation coefficients (ICC) and Bland-Altman analysis were used to assess intra- and interobserver variability. E-Cervix parameters during the three trimesters were compared using the Friedman test.

RESULTS

In total, 217 women with 651 strain examinations during the three trimesters were included. The intra- and interobserver ICC for the E-Cervix parameters ranged from 0.947 to 0.991 and 0.855 to 0.989, respectively. There were significant differences in all parameters among the three trimesters. Cervical elasticity showed significant softening and became heterogeneous during the three trimesters. The median CL was significantly shorter in the first trimester than in the second and third trimesters (P = 0.004, P < 0.001).

CONCLUSION

E-Cervix provides a graphical tool for operators to easily define regions of interest and obtain multiple repeatable measures of elasticity. The normal references for E-Cervix parameters during the three trimesters reflect the physiological cervical changes during pregnancy.

Quantitative and Qualitative Evaluation of Breast Cancer Prognosis: A Sonographic Elastography Study

Background

Breast cancer is one of the most commonly diagnosed cancers in women worldwide, and sonographic elastography has previously demonstrated good performance in detecting breast malignancies. However, the exact relationship between elastographic measures and clinical prognostic factors is still not well understood. Thus, the aim of this study was to evaluate any associations between major clinical prognostic factors and strain elastography and to validate the diagnostic value of elastography in breast cancer.

Material/Methods

A total of 373 subjects with breast masses, of which 196 were benign and 177 were malignant, were included in the study. All subjects underwent routine ultrasound examination and strain elastography before biopsy. The elastographic measures – strain ratio (SR) for qualitative measures and Tsukuba score (TS) for quantitative measures – were obtained and compared with prognostic factors, including nuclear grade, lymph node status, estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor 2 (HER-2). The SR demonstrated the best diagnostic performance in differentiation between malignant and benign lesions.

Results

With the best cut-off value at 2.42, the SR achieved a sensitivity of 96.0% and specificity of 98.5%. Moreover, higher SRs and TSs were associated with breast lesions with a high nuclear grade and lymph node metastasis and with being ER-negative, PR-negative, and HER-2 negative.

Conclusions

Elastography is a useful imaging technique in differentiating benign breast masses from malignant ones. The strong relationship between prognostic factors and elastographic measures also demonstrated its excellent performance in predicting the prognosis of breast malignancies.

The predictive value of cervical shear wave elastography in the outcome of labor induction

Introduction

Bishop score, the traditional method to assess cervical condition, is not a promising predictive tool of the outcome of labor induction. As an objective assessment tool, many cervical ultrasound measurements have been proposed to represent the individual components of the Bishop score, but none of them can measure the cervical stiffness. Cervical shear wave elastography is a novel tool to assess the cervical stiffness quantitatively.

Material and methods

A total of 475 women who required labor induction were studied prospectively. Prior to routine digital assessment of the Bishop score, transvaginal sonographic measurement of cervical length, posterior cervical angle, angle of progression and shear wave elastography was performed. Shear wave elastography measurement was made at the inner, middle and outer regions of the cervix to assess homogeneity. Association of labor induction outcomes including the overall cesarean section and subgroups of cesarean section for failure to enter active phase, with cervical sonographic parameters and the Bishop score, were assessed using multivariate regression analyses. The predictive accuracy of the outcomes using models based on ultrasound measurement and the Bishop score was compared using the area under the receiver‐operating characteristics curves.

Results

Among 475 women, 82 (17.3%) required cesarean section. Shear wave elasticity was significantly higher in the inner cervical region than in other regions, indicating a greater stiffness (P < 0.001). Both inner cervical shear wave elasticity and cervical length were independent predictors of overall cesarean section (respective adjusted odds ratio [95% CI] 1.338 [1.001‐1.598] and 1.717 [1.077‐1.663]) and cesarean section for failure to enter active phase (respective adjusted odds ratio [95% CI] 1.689 [1.234‐2.311] and 2.556 [1.462‐4.467]), after adjusting for other covariates. Outcome prediction models using inner cervical shear wave elasticity and cervical length, had increased area under curve compared with models using the Bishop score (0.888 vs 0.819, P = 0.009).

Conclusions

The cervix is not a homogenous structure, with the inner cervix having the highest stiffness, which is an independent predictor of overall cesarean section, and specifically for those indicated because of failure to enter active phase. Models based on shear wave elastography and cervical length had higher predictive accuracy than models based on the Bishop score.

Diagnostic accuracy of cervical elastography in predicting preterm delivery: A systematic review and meta-analysis

BACKGROUND

The aim of the study was to evaluate the diagnostic accuracy of cervical elastography in predicting preterm delivery (PTD).

METHODS

We searched the PubMed, EMBASE, and Cochrane databases to identify relevant studies that applied ultrasound (US) elastography to assess cervical stiffness and predict PTD. All the studies were published before December 11, 2018, and only studies published in English were collected. The cervical length (CL) was considered a comparator, and the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool was applied to assess the quality of the included studies. Summary receiver operating characteristic (SROC) modeling was performed to evaluate the diagnostic performance of cervical elastography in predicting PTD. Subgroup analyses were also performed.

RESULTS

Seven studies, including 1488 pregnant women, were included in this meta-analysis. Cervical elastography showed a summary sensitivity of 0.84 [95% confidence interval (CI): 0.68, 0.93], a specificity of 0.82 (95% CI: 0.63, 0.93), a diagnostic odds ratio of 25 (95% CI: 7, 93), and an area under the curve (AUC) of SROC of 0.90 (95% CI: 0.87-0.93). CL measurement showed that the AUC of SROC was 0.60 (95% CI: 0.56-0.64). The results of subgroup analysis showed that the summary sensitivity and specificity were different in the QUADAS-2 score subgroups.

CONCLUSION

Cervical elastography is a promising and reliable method to predict PTD. Cervical elastography showed better diagnostic performance to predict PTD than CL measurement.

Gestational age-related changes in shear wave speed of the uterine cervix in normal pregnancy at 12-35 weeks' gestation

Background This study aimed to analyze age-related changes in shear wave speed (SWS) of the normal uterine cervix. Methods We studied 362 women with a normal singleton pregnancy at 12-35 weeks' gestation. The SWS of the cervix was measured using transvaginal ultrasonography at the internal os region of the anterior cervix (IOA), posterior cervix (IOP) and cervical canal (IOC), and at the external os region of the anterior cervix (EOA), posterior cervix (EOP) and cervical canal (EOC). The following parameters were analyzed: (1) time trend of SWS of the individual sampling points, (2) comparison of SWS in the internal cervical region and SWS in the external cervical region, and (3) comparison of SWS between the internal and external cervical regions. Statistical analyses were performed using mixed-effects models. Results The SWS of IOP decreased in bilinear regression, with a critical change in the rate at 22 weeks, whereas the SWS of the remaining points decreased linearly. The estimated values of SWS of IOP at 84, 154 and 251 days were higher than those of IOA and IOC (P<0.001). The estimated values of SWS of IOP at 84 and 154 days were higher than those of EOP (P<0.001). Significant differences between IOP and EOP were shown until 244 days (P<0.05). The estimated value of SWS of IOC at 84 days was higher than that of EOC (P<0.001). Significant differences between IOC and EOC were shown until 210 days (P<0.05). Conclusion The SWS of the uterine cervix in pregnancy decreases with advancing gestation. The SWS of IOP had the highest value among the sampling points with unique characteristics.

Addition of Cervical Elastography May Increase Preterm Delivery Prediction Performance in Pregnant Women with Short Cervix: a Prospective Study

BACKGROUND

We investigated whether there is a difference in elastographic parameters between pregnancies with and without spontaneous preterm delivery (sPTD) in women with a short cervix (≤ 25 mm), and examined the ability of elastographic parameters to predict sPTD in those women.

METHODS

E-Cervix^TM (WS80A; Samsung Medison, Seoul, Korea) elastography was used to examine the cervical strain. Elastographic parameters were compared between pregnancies with and without sPTD. Diagnostic performance of elastographic parameters to predict sPTD ≤ 37 weeks, both alone and in combination with other parameters, was compared with that of cervical length (CL) using area under receiver operating characteristic curve (AUC) analysis.

RESULTS

A total of 130 women were included. Median gestational age (GA) at examination was 24.4 weeks (interquartile range, 21.4-28.9), and the prevalence of sPTD was 20.0% (26/130). Both the elastographic parameters and CL did not show statistical difference between those with and without sPTD. However, when only patients with CL ≥ 1.5 cm (n = 110) were included in the analysis, there was a significant difference between two groups in elasticity contrast index (ECI) within 0.5/1.0/1.5 cm from the cervical canal (P < 0.05) which is one of elastographic parameters generated by E-Cervix. When AUC analysis was performed in women with CL ≥ 1.5 cm, the combination of parameters (CL + pre-pregnancy body mass index + GA at exam + ECI within 0.5/1.0/1.5 cm) showed a significantly higher AUC than CL alone (P < 0.05).

CONCLUSION

An addition of cervical elastography may improve the ability to predict sPTD in women with a short CL between 1.5 and 2.5 cm.

Acoustic radiation force impulse (ARFI) elastography to asses maternal and foetal structures in pregnant ewes

The aim of this study was to evaluate the stiffness of foetal lungs, liver, kidneys and placentomes by acoustic radiation force impulse (ARFI) elastography in ovine and to correlate obtained findings with foetal development. Twenty-four ewes were included, and tissue stiffness of foetal lung, liver, kidney and placentome was measured beginning with 10th gestational week by qualitative-quantitative ARFI elastography. A total of 33 healthy lambs were born. Qualitative elastographic analysis permitted to classify maternal and foetal tissues elasticity in decreasing order as follows: placentome, kidney, liver and lung. Regarding quantitative ARFI elastography data, shear wave velocity (SWV) of foetal lung and liver varied. The lung SWV decreased gradually from the 16th to the 21st gestational week (R²  = 0.80; p < 0.001), while liver SWV increased gradually from the 14th to 21st gestational week (R²  = 0.80; p < 0.001). In contrast, the kidneys and placentomes SWV's remained constant through gestation (p = 0.076; and 0.34). ARFI elastography was shown feasible for evaluation of maternal and foetal tissues stiffness in the ovine model. It can be used to demonstrate pulmonary and hepatic stiffness modifications during foetal development.

New techniques in evaluation of the cervix

The process of parturition is poorly understood, but the cervix clearly plays a key role. Because of this, recent research efforts have been directed at objective quantification of cervical remodeling. Investigation has focused on two basic areas: (1) quantification of tissue deformability and (2) presence, orientation, and/or concentration of microstructural components (e.g. collagen). Methods to quantify tissue deformability include strain elastography and shear wave elasticity imaging (SWEI). Methods to describe tissue microstructure include attenuation and backscatter. A single parameter is unlikely to describe the complexities of cervical remodeling, but combining related parameters should improve accuracy of cervical evaluation. This chapter reviews options for cervical tissue characterization.

Cervical elastography during pregnancy: clinical perspectives

Uterine cervix is a part of the uterus responsible for maintaining pregnancy till term. As long as the cervix remains long and firm and its internal orifice (os) is closed, it can withstand enlargement of the uterine contents and resultant growing pressure. Mechanical properties of the cervix change during pregnancy; the cervix ripens prior to delivery, then effaces and dilates with contractions of the uterus. Ripening of the cervix can be assessed using the Bishop score and ultrasonographically determined length of the cervical canal and internal os. Consistency is one of the cervical properties that change during the course of the maturation process. Until recently, cervical consistency has been assessed only manually, but in 2007, the first report on elastographic imaging of the cervix during pregnancy has been published. Elastography presents the ability of a tissue to deform under pressure. The softer the tissue, the easier it changes its shape. Different methods of elastography are used - static, when tissue displacement in response to manual compression or physiological movements of vessels is measured, or dynamic, when the speed of shear wave propagation is determined. Irrespective of the method, elastography provides information on the internal os stiffness; this parameter, impossible for manual assessment, was shown to correlate with pregnancy outcome and is a strong predictor of preterm delivery or successful labor induction. Although elastography seems to be a highly promising diagnostic option, still no consensus has been reached regarding an optimal method for uterine cervix assessment, and virtually all previous studies of various elastographic methods produced highly satisfactory results. Future studies need to identify the most promising and objective elastographic method which may serve as a novel tool for pregnancy management, preventing adverse events, such as preterm delivery and unsuccessful labor induction.

Elastographic measurement of the cervix during pregnancy: Current status and future challenges

The cervix is a cylindrical structure that is proximally connected to the uterus and distally to the vaginal cavity. The Bishop score has been used to evaluate the cervix during pregnancy. However, alternatives have been evaluated because the Bishop score is uncomfortable for patients, relies on a subjective examination, and lacks internal os data. Elastography has been used to assess the cervix, as it can estimate tissue stiffness. Recent articles on elastography for cervical assessment during pregnancy have focused on its usefulness for prediction of preterm birth and successful labor induction. There is a clinical need for cervical elastography, as an evaluation of biomechanical factors, because cervical length only assesses morphological changes. However, until now, cervical elastography has been studied in the limited field, and not shown a uniformed methodological technique. In this review, the current status, limitations, and future possibility of cervical elastography were discussed. Future studies should focus on overcoming the limitations of cervical elastography. Although the cervical elastography is presently an incompletely defined technique, it needs to be improved and evaluated as a method for use in combination with cervical length.

Elastography Improves the Diagnostic Accuracy of Sonography in Differentiating Endometrial Polyps and Submucosal Fibroids

OBJECTIVES

To assess whether strain elastography may be used to visualize the different stiffness of endometrial polyps and submucosal fibroids.

METHODS

We conducted a prospective monocentric single-operator study on diagnostic accuracy. Patients who qualified for hysteroscopy because of suspected endometrial polyps and submucosal fibroids were included. Before the procedure, all patients underwent routine sonographic and power Doppler examinations. Additionally, the stiffness of intrauterine lesions was assessed by strain elastography. The enhancement was adjusted to visualize hard myometrium and soft endometrium around the intrauterine lesion. Due to their histologic structure, we assumed that on strain elastography, endometrial polyps should appear as soft lesions, whereas submucosal fibroids should appear as hard lesions. Sonographic, power Doppler, and elastographic findings were verified by pathologic examinations after hysteroscopies. The diagnostic accuracy of sonography, power Doppler imaging, and strain elastography was compared by the McNemar test.

RESULTS

Forty-seven patients were included and underwent hysteroscopy. In 29 cases, endometrial polyps were found, and in 18, submucosal fibroids were found. The diagnostic accuracy rates for B-mode sonography, power Doppler imaging, and strain elastography in distinguishing endometrial polyps and submucosal fibroids were 70.2%, 65.9%, and 89.4%, respectively. The proportion of correct findings was significantly higher for strain elastography than for B-mode sonography (P = .0265) and power Doppler imaging (P = .0153).

CONCLUSIONS

Strain elastography complements sonography in differentiating intrauterine lesions. Strain elastography may be used to visualize the different stiffness of endometrial polyps and submucosal fibroids.

Is evaluation of placenta with real-time sonoelastography during the second trimester of pregnancy an effective method for the assessment of spontaneous preterm birth risk?

PURPOSE

The aim of this study is to investigate the effectiveness of placental strain ratio (SR) values measured by real-time sonoelastography (SE) in the second trimester in the prediction of spontaneous preterm birth (sPTB).

METHODS

This study included 70 pregnant women who applied to our clinic for routine second-trimester screening. Placental SR measurements were performed with the SE method. Two different SR measurements were performed by taking two different tissues as references. The SR value measured when taking the rectus abdominis muscle as a reference was termed the muscle-to-placenta strain ratio (MPSR), while the SR value measured when taking subcutaneous tissue as a reference was termed the fat-to-placenta strain ratio (FPSR). Women whose gestational age at birth was less than 37 weeks 0 days were accepted as sPTB. The association between gestational age at birth and MPSR and FPSR was investigated. Receiver operating characteristics analysis was used to calculate the sensitivity and specificity of the elastographic outcomes.

RESULTS

There was a low-level negative correlation between MPSR and gestational age at birth (r=-0.300, P=.012) and there was a moderate-level negative correlation between FPSR and gestational age at birth (r=-0.513, P<.001). The multivariate linear regression analysis showed that the FPSR (β=0.609, P=.002) was the significant predictor for the sPTB.

CONCLUSIONS

Our data indicate that the FPSR value measured with real-time SE in the second trimester of pregnancy may be effective in the prediction of sPTB.

Changes in ectocervical surface area in women throughout pregnancy compared to non-pregnant and postpartum states

OBJECTIVE

The objective of this study is to estimate changes in the surface area of the ectocervix (CA) in women during pregnancy and compare this to postpartum and non-pregnant states.

METHODS

CA was evaluated in 210 normal nulliparous women divided into groups from early to late gestation, 40 postpartum women, and 25 non-pregnant women. CA in cm(2) was estimated from analysis of images taken with an endoscope of the cervical face and an mm scale. An mm scale was also used to determine fornix length and fornix area computed.

RESULTS

The face, fornix, and total areas of the CA of non-pregnant and postpartum groups are significantly smaller (p < 0.001) than these areas in groups during pregnancy. Generally, the CA of the face, fornix, and total area are also less in early pregnancy compared with late gestation (p < 0.01 to <0.001). Total CA correlates with gestational age (r = 0.196, p < 0.004).

CONCLUSIONS

(1) During pregnancy, CA slowly and progressively increases to >75% area compared with CA of non-pregnant patients and then reverts back to low CA postpartum. (2) Increases in CA during pregnancy occur in both the face and fornix areas. (3) Increases in CA reflect enlargement in cervical volume and remodeling during pregnancy.

Feasibility and reproducibility of ShearWave(TM) elastography of fetal baboon organs

OBJECTIVES

The purpose of this study was to assess the feasibility and reproducibility of transabdominal ShearWave(TM) elastography of fetal organs in pregnant baboons.

MATERIALS AND METHODS

Fetal ultrasounds of all pregnant baboons in a single primate research center were performed prospectively during 9 months. The visualization of fetal targeted organs (liver, proximal and distal lungs, brain white matter and periventricular gray matter) was initially performed using 2D ultrasound, and then elastography mode was activated. For each organ, three measurements were carried out by two operators. Intra-observer and inter-observer intra-class correlation coefficients (ICC) were calculated.

RESULTS

During the study period (03/2013-12/2013), 21 pregnant baboons (21 fetuses) were included. One to three ultrasound scans were performed for each fetus. The measurements were feasible by the two operators in all cases. The intra-observer and inter-observer ICC were 0.654, 95% CI (0.606 to 0.699) and 0.645, 95% CI (0.553 to 0.721) respectively.

CONCLUSION

Transabdominal ShearWave(TM) Elastography of fetal organs can be achieved in pregnant baboons. The intra-observer and inter-observer reproducibility is correct but vary according to the targeted organs.

[Shear waves elastography of the placenta in pregnant baboon]

OBJECTIVES

To evaluate tissue characteristics of the placenta by transabdominal ShearWave Elastography in pregnant baboon.

MATERIALS AND METHOD

For 9 months (03/2013-12/2013) two operators (EQ, GG) performed ultrasound of the placenta during pregnancy pregnant baboons station partner primatology project. The identification of the placenta was performed previously in 2D ultrasound. The elastography method was then activated. Three measurements were carried out by operator for each placenta. The intraclass correlation coefficients within and between observers were calculated for the objective assessment (elastography) of placental maturity.

RESULTS

During the study period, 21 pregnant baboons were included and ultrasounds were performed between 1 and 3 times each. The measurements have been carried out by two operators in 100% of cases. The intra- and inter-observer ICC for single values are respectively 0.657 - 95% CI (0.548 to 0.752) and 0.458 - 95% CI (0.167 to 0.675). The intra- and inter-observer ICC for average values are respectively 0.852 - 95% CI (0.784 to 0.901) and 0.628 - 95% CI (0.286 to 0.806).

CONCLUSION

The study by transabdominal ShearWave Elastography of placenta's pregnant baboons is possible. The intra- and inter-operator reproducibility of this method is good using the average of three measurements. The objective study via elastography ShearWave of the degree of placental maturity seems not yet be used in clinical practice. Studies of larger cohorts are needed.

The history of imaging in obstetrics

During the past century, imaging of the pregnant patient has been performed with radiography, scintigraphy, computed tomography, magnetic resonance imaging, and ultrasonography (US). US imaging has emerged as the primary imaging modality, because it provides real-time images at relatively low cost without the use of ionizing radiation. This review begins with a discussion of the history and current status of imaging modalities other than US for the pregnant patient. The discussion then turns to an in-depth description of how US technology advanced to become such a valuable diagnostic tool in the obstetric patient. Finally, the broad range of diagnostic uses of US in these patients is presented, including its uses for distinguishing an intrauterine pregnancy from a failed or ectopic pregnancy in the first trimester; assigning gestational age and assessing fetal weight; evaluating the fetus for anomalies and aneuploidy; examining the uterus, cervix, placenta, and amniotic fluid; and guiding obstetric interventional procedures.

The role of sonographic cervical length in labor induction at term

The purpose of this study is to review the literature examining the role of ultrasound in the induction of labor. Databases including Ovid, PubMed, Web of Science, Google Scholar, and UpToDate were searched and current guidelines from the SOGC, the ACOG, the RCOG, and the RANZCOG were reviewed. Although studies have not demonstrated the superiority of cervical sonography to the Bishop score, the evidence indicates that sonography could be useful in planning induction of labor, significantly reducing the need for cervical ripening agents. A more comprehensive method integrating both sonography and digital exam may be more appropriate.

Intrapartum ultrasound: A useful method for evaluating labor progress and predicting operative vaginal delivery

The last step of a successful pregnancy is the safe delivery of the fetus. An important question is if the delivery should vaginal or operative. In addition to the use of conventional antenatal ultrasound, the use of intrapartum ultrasound to evaluate fetal head station, position, cervical ripening, and placental separation is promising. This review evaluates and summarizes the usefulness of intrapartum ultrasound for the evaluation of labor progress and predicting successful operative vaginal delivery.

Successful induction of labor: prediction by preinduction cervical length, angle of progression and cervical elastography

OBJECTIVE

To examine the potential value of preinduction cervical length, cervical elastography and angle of progression (AOP) in prediction of successful vaginal delivery and induction-to-delivery interval.

METHODS

This was a prospective study in 99 women with singleton pregnancy undergoing preinduction ultrasound assessment at 35-42 weeks' gestation. Cervical length, elastographic score at the internal os and AOP were determined. Regression analysis was used to assess the relationship between cervical length and both AOP and elastographic score. Logistic regression analysis was used to determine which of the maternal characteristics (cervical length, AOP, elastographic score) were significant predictors of vaginal delivery and induction-to-delivery interval.

RESULTS

Vaginal delivery occurred in 66 (66.7%) cases and Cesarean delivery was performed in 33 (33.3%) cases. There were significant correlations between cervical length and both AOP (r = - 0.319) and elastographic score (r = 0.368). Significant independent prediction of vaginal delivery and induction-to-delivery interval was provided by nulliparity and cervical length, with no additional significant contribution from electrographic score or AOP.

CONCLUSIONS

In women undergoing induction of labor, AOP and elastographic score at the internal os are unlikely to be useful in prediction of vaginal delivery and induction-to-delivery interval.

Overview of the methods available for biomechanical testing of the uterine cervix in vivo

OBJECTIVE

To give an overview of the methods available for biomechanical testing of the non-pregnant and pregnant uterine cervix in vivo.

METHODS

The following databases were searched. PubMed, Embase, and Cochrane Library. Additional studies were identified from reference lists. Only studies on in vivo biomechanical testing on both pregnant and non-pregnant women were included.

MAIN OUTCOME MEASURES

Estimation of distensibility, compressibility, and biochemical composition of the uterine cervix.

RESULTS

The distensibility methods evaluated a physiologic variable and might serve as a gold standard; however, they may never be clinically useful as they involve instrumentation of the cervical canal. The compression methods evaluated an unphysiological variable but despite that, they seemed to evaluate biologically relevant figures and were non-invasive. Of the methods evaluating the biomechanical properties indirectly, those based on ultrasound may be clinically useful. Other indirect methods only measured variables within the most superficial layer of the distal uterine cervix, so further studies are needed to evaluate whether these measurements reflect the entire organ. Both compression methods and indirect methods were similar or superior to the Bishop score and to cervical length measurements regarding prediction of spontaneous preterm delivery and successful induction of labor in small studies.

CONCLUSION

The methods may have the potential to detect the biomechanical changes in the uterine cervix before the cervical length has shortened. The most promising methods need large-scale clinical testing regarding induction of labor and preterm delivery before they can be used in the clinic.

Effect of depth on shear-wave elastography estimated in the internal and external cervical os during pregnancy

AIM

To investigate the effect of depth on cervical shear-wave elastography.

METHODS

Shear-wave elastography was applied to estimate the velocity of propagation of the acoustic force impulse (shear wave) in the cervix of 154 pregnant women at 11-36 weeks of gestation. Shear-wave speed (SWS) was evaluated in cross-sectional views of the internal and external cervical os in five regions of interest: anterior, posterior, lateral right, lateral left, and endocervix. Distance from the center of the ultrasound (US) transducer to the center of each region of interest was registered.

RESULTS

In all regions, SWS decreased significantly with gestational age (P=0.006). In the internal os, SWS was similar among the anterior, posterior, and lateral regions and lower in the endocervix. In the external os, the endocervix and anterior regions showed similar SWS values, lower than those from the posterior and lateral regions. In the endocervix, these differences remained significant after adjustment for depth, gestational age, and cervical length. SWS estimations in all regions of the internal os were higher than those of the external os, suggesting denser tissue.

CONCLUSION

Depth from the US probe to different regions in the cervix did not significantly affect the SWS estimations.