Article

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?

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Abstract

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.

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... Изследван е рискът от ПР дали може да бъде измерван като се използва стойността на съотношението на плацентарното преразтягане (SR), измерена през втория триместър, използвайки соноеластография в реално време [44]. При 70 бременни жени във втория триместър са използвани две различни тъкани като референти. ...
... Те използват трансвагинална ултрасонография за измерване на CCI и дължината на шийката, като показват, че CCI е значителен предиктор за раждане преди 37 г.с. Конвенционалните методи за диагностика на ПР, като измерване на дължината и консистенцията на шийката на матката, прогнозират около 55% до 69% от случаите на спонтанно ПР [42][43][44]47]. ...
Article
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Преждевременното раждане е сложен медицински проблем, който се дължи на множество етиологични фактори, включително генетични, инфекциозни, имунологични и екологични влияния. Прогнозирането и предотвратяването на раждане преди 37-та гестационна седмица представлява значително предизвикателство в пренаталната медицина поради разнообразието от етиологични фактори. Предвестниците на предтерминно раждане, които сигнализират за възможността от появата му, са от изключителна важност за предотвратяването му. Ехографското изследване отдавна е идентифицирано като един от най-добрите предиктори за преждевременно раждане. Измерването на дължината на маточната шийка е най-широко използван в съвременната клинична практика метод за прогнозирането на предстоящо раждане. Настоящата публикация има за цел да представи и анализира методите за прогнозиране на преждевременно раждане.
... Pulsatility of the uterine artery in the peak of uterine contractions in women at risk of having preterm labor was significantly higher for women who had their baby after seven days of gestation [16], [17]. ...
... The strain ratio of the placenta, determined using realtime sonoelastography, was found to be negatively associated with gestational age at birth, and it was suggested that it could be a reliable predictor for PB [17]. ...
Article
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... The stiffness of a targeted tissue is expressed as strain ratio, the strain of targeted tissue to the strain of reference tissue. In several implementations, maternal fat tissues were used as the reference tissue (Cimsit et al., 2015b;Albayrak et al., 2016). A major difficulty, however, is reproducibility. ...
... Furthermore, it is difficult to maintain constant palpation among operators, and readings between patients can be difficult to compare. In Albayrak et al. study, fat-to-placenta strain ratio was reported from SE instead and showed a large variability in his results, range from 0.2 to 14.0 for normal placenta (Albayrak et al., 2016). On top of palpation inconsistency, this large variability of the readings could also be due to person-to-person variability of fat tissue stiffness, which acted as the reference tissue. ...
Article
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Placenta is an important organ that is crucial for both fetal and maternal health. Abnormalities of the placenta, such as during intrauterine growth restriction (IUGR) and pre-eclampsia (PE) are common, and an improved understanding of these diseases is needed to improve medical care. Biomechanics analysis of the placenta is an under-explored area of investigation, which has demonstrated usefulness in contributing to our understanding of the placenta physiology. In this review, we introduce fundamental biomechanics concepts and discuss the findings of biomechanical analysis of the placenta and umbilical cord, including both tissue biomechanics and biofluid mechanics. The biomechanics of placenta ultrasound elastography and its potential in improving clinical detection of placenta diseases are also discussed. Finally, potential future work is listed.
... The consideration of funneling alongside short CL has previously shown to increase sensitivity from 61 to 74% for PTB [77]. However, funneling is not indicative enough to be considered as an independent risk factor when CL is normal; it, therefore, provides very limited impact from a clinical standpoint, and adds little value in the prediction of PTB when used alone [77][78][79][80]. ...
... Albayrak et al. analyzed the placenta and found that the placental strain ratio has shown some promise in the prediction of PTB. This is because the fat-to-strain placenta ratio (FPSR) can be used as an indicator of PTB [79]. ...
Preprint
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Preterm birth (PTB) is the leading cause of neonatal morbidity and mortality worldwide. The ability to predict patients at risk for preterm birth remains a major health challenge. The currently available clinical diagnostics such as cervical length and fetal fibronectin may detect only up to 30% of patients who eventually experience a spontaneous preterm birth. This paper reviews ongoing efforts to improve the ability to conduct a risk assessment for preterm birth. In particular, this work focuses on quantitative methods of imaging using ultrasound-based techniques , magnetic resonance imaging, and optical imaging modalities. While ultrasound imaging is the major modality for preterm birth risk assessment, a summary of efforts to adopt other imaging modalities is also discussed to identify the technical and diagnostic limits associated with adopting them in clinical settings. We conclude the review by proposing a new approach using combined photoacoustic, ultrasound, and elastography as a potential means to better assess cervical tissue remodeling, and thus improve the detection of patients at-risk of PTB. ARTICLE HISTORY
... Some authors have recently studied the placenta by US elastography [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36], but we propose a new method for this analysis. The field of elastography covers many different US techniques, based on physical approaches that are sometimes quite distant from one another [37][38][39][40] (Fig 1). ...
... Moreover, they have employed a diverse range of elastography techniques: strain elastography [19,26,30], ARFI [20,28,[32][33][34], or SWE [21,22,25,27,29]. The orders of magnitude of the measurements sometimes differed from one study to another. ...
Article
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Background Placental elasticity may be modified in women with placental insufficiency. Shear wave elastography (SWE) can measure this, using acoustic radiation force, but the safety of its use in pregnant women has not yet been demonstrated. Transient elastography (TE) is a safer alternative, but has not yet been applied to the placenta. Moreover, the dispersion of shear wave speed (SWS) as a function of frequency has received relatively little study for placental tissue, although it might improve the accuracy of biomechanical assessment. Objective To explore the feasibility and reproducibility of TE for placental analysis, to compare the values of SWS and Young’s modulus (YM) from TE and SWE, and to analyze SWS dispersion as a function of frequency ex vivo in normal placentas. Materials and methods Ten normal placentas were analyzed ex vivo by an Aixplorer ultrasound system as shear waves were generated by a vibrating plate and by using an Aixplorer system. The frequency analysis provided the value of the exponent n from a fractional rheological model applied to the TE method. We calculated intra- and interobserver agreement for SWS and YM with 95% prediction intervals, created Bland-Altman plots with 95% limits of agreement, and estimated the intraclass correlation coefficient (ICC). Main results The mean SWS was 1.80 m/s +/- 0.28 (standard deviation) with the TE method at 50 Hz and 1.82 m/s +/-0.13 with SWE (P = 0.912). No differences were observed between the central and peripheral regions of placentas with either TE or SWE. With TE, the intraobserver ICC for SWS was 0.68 (0.50–0.82), and the interobserver ICC for SWS 0.65 (0.37–0.85). The mean parameter n obtained from the fractional rheological model was 1.21 +/- 0.12, with variable values of n for any given SWS. Conclusions TE is feasible and reproducible on placentas ex vivo. The frequency analysis of SWS provides additional information about placental elasticity and appears to be able to distinguish differences between placental structures.
... Эластография также может применяться для определения коэффициента деформации плаценты с целью прогнозирования СПР. Многофакторный линейный регрессионный анализ показал, что коэффициент деформации плаценты (β = 0,609, P = 0,002) является значимым предиктором ПР и может быть эффективным для прогнозирования СПР [38]. ...
Article
Актуальность: Преждевременные роды (ПР) являются ведущей проблемой здравоохранения во всем мире и в настоящее время считаются основной причиной смерти новорожденных. Ежегодно во всем мире приблизительно 15 миллионов детей рождаются недоношенными, что составляет около 11% всех родов в мире. Поскольку этиология ПР не совсем ясна, идентификация факторов риска и определение индивидуального риска имеют важное значение в ведении беременных женщин. Несмотря на значительные усилия, направленные на снижение частоты спонтанных ПР (СПР), они остаются ведущей причиной перинатальной заболеваемости и смертности. Имеющиеся стратегии скрининга несовершенны.Цель исследования – изучение и анализ текущих данных касательно факторов риска и предикторов для прогнозирования преждевременных родов.Материалы и методы: В обзор включены опубликованные данные касательно факторов риска и предикторов СПР за последние 10 лет. Поиск литературы проводился в базах данных Medline, Scopus, Web of Science, Google Scholar, PubMed, Wiley и Cochrane Library. Поиск осуществлялся по ключевым словам: «спонтанные преждевременные роды», «предикторы преждевременных родов», «факторы риска преждевременных родов» с использованием MeSH.Результаты: Из всех известных факторов, ПР в анамнезе и невынашивание являются ведущими факторами риска СПР. Цервикометрия, или измерение длины шейки матки при ультразвуковом исследовании, является распространенным и довольно эффективным методом прогнозирования СПР. Фетальный фибронектин является одним из распространённых маркеров для прогнозирования ПР. Помимо шеечных факторов, маркеры сыворотки крови матери тоже предложены для прогнозирования ПР.Заключение: Выявление факторов риска СПР является важным компонентом акушерской помощи в связи с эффективностью ранних вмешательств для снижения риска ПР. Не существует единого или комбинированного метода скрининга ПР с высокой чувствительностью, который действительно выявлял бы женщин с риском ПР, а также с высокой специфичностью для предотвращения ненужных вмешательств и высоких затрат на лечение. Цервикометрия является наиболее экономичным методом в клинической практике. Исследования по метаболомике и протеомике, а также профилирование микроРНК привнесли новый аспект в эту тему. Возможно, в будущем, при четком выявлении женщин с истинным риском ПР, появится возможность разработки более эффективных превентивных стратегий.
... Maternal risk factors such as personal history of preterm birth, cervical excisional procedures, smoking status, use of assisted reproductive techniques, vaginal and urinary tract infections, thrombotic disorders, or ischemic placental disease have been proposed as predictors of PTB (4)(5)(6)(7)(8). Moreover, sonographic markers such as short cervical length, uterocervical angle, uterine artery pulsatility index, as well as cervical and elastography parameters, have proven to be associated with increased risk of preterm birth and adverse pregnancy outcomes (9)(10)(11)(12). ...
Article
The prediction of preterm birth (PTB) is still a controversial topic, and many efforts have been made to identify the best predictive markers. The aim of this study was to prospectively assess the predictive performance of placental alpha macroglobulin-1 (PAMG-1), fetal fibronectin (fFN), and cervical length, both individually and combined, for the prediction of spontaneous preterm birth at 7 and 14 days in a cohort of pregnant patients with threatened preterm labor. Material and methods: Between October 2022 and April 2023, we performed a prospective observational study that evaluated 80 pregnant patients with singleton pregnancies, between 24 and 32 completed weeks of gestation. We qualitatively determined PAMG-1 (PartoSure test) and fFN from the vaginal fluid. Clinical data along with cervical length measurements were also retrieved. The predictive performance of the evaluated markers was determined using logistic regression and ROC analysis. Results: PartoSure obtained the best results for the prediction of PTB in the next 7 or 14 days. On the other hand, cervical length, at an established cut-off of 19 mm, had the lowest predictive performance for the evaluated outcomes. A combined algorithm that comprised PartoSure, fFN, and cervical length measurements achieved the best predictive performance for the prediction of PTB at 14 days. Conclusions: The combined algorithm is superior in terms of predictive performance for the prediction of PTB in the next 7 or 14 days. The PartoSure test could be used individually for the prediction of PTB, but clinicians need to correlate its results with other clinical findings.
... Other ultrasound markers were described as a tool for prediction such as: fetal membrane thickness, uterine artery pulsatility index during the peak of uterine contractions, placental strain ratio, fetal middle cerebral artery pulsatility index (MCA-PI) and measurements of the central zone of the fetal adrenal gland. They all usually require expertise and their exact predictive values are yet to be studied [11]. In addition, amniotic fluid indicates certain factors such as low glucose, low interleukin-6 (IL-6), high vascular endothelia growth factor (VEGF) and placental growth factor (PGF) and low soluble VEGF resecptor-1 (sFLt-1) [12]. ...
Article
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Background: Preterm labor and delivery remain a major problem in obstetrics accounting for perinatal morbidity and mortality. The challenge is to identify those with true preterm labor to avoid unnecessary hospital admissions. The fetal fibronectin (FFN) test is a strong predictor of preterm birth and can help identify women with true preterm labor. However, its cost-effectiveness as a strategy for triaging women with threatened preterm labor is still debatable. Objective: To evaluate the effect of FFN test implementation on hospital resources by reducing the admission rate of threatened preterm labor in a tertiary hospital, Latifa Hospital, UAE. Methods: A retrospective cohort study of singleton pregnancies between 24 and 34 weeks of gestation who attended Latifa Hospital in the period of September 2015–December 2016, complaining of threatened preterm labor after the availability of an FFN test, and a historical cohort study for those who attended with threatened preterm labor before the availability of an FFN test. Data analysis was performed using a Kruskal–Wallis test, Kaplan–Meier, Fischer exact chi-square and cost analysis. The significance was set at p-value < 0.05. Results: In total, 840 women met the inclusion criteria and were enrolled. The relative risk of FFN for delivery at term was 4.35 times higher among the negative-tested compared to preterm delivery (p-value < 0.001). A total of 134 (15.9%) women were unnecessarily admitted (FFN tested negative, delivered at term) which yielded $107,000 in extra costs. After the introduction of an FFN test, a 7% reduction of threatened preterm labor admissions was recorded.
... After the first exploratory study on placental elasticity evaluation in 2012 (Li et al. 2012), several studies have been conducted with the objectives of establishing baseline elasticity for normal placenta tissue (McAleavey et al. 2016;Abeysekera et al. 2017;Calle et al. 2018) and understanding the changes in placental stiffness resulting from pregnancy complications such as pre-eclampsia (PE) (Cimsit et al. 2015;Kiliç et al. 2015;Alan et al. 2016;Karaman et al. 2016;Fujita et al. 2019;Spiliopoulos et al. 2020), intrauterine growth restriction (IUGR) (Sugitani et al. 2013;Ohmaru et al. 2015;Durhan et al. 2017;Habibi et al. 2017;Eroglu et al. 2020), pre-term birth (Albayrak et al. 2016) and gestational diabetes mellitus (GDM) (Yuksel et al. 2016;Bildaci et al. 2017;Lai et al. 2020). These complications fall within the spectrum of "great obstetrical syndromes," a term indicating their association with structural and functional changes of the placenta (Romero and Romero 2009;Gabbay-Benziv and Baschat 2015). ...
Article
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Pregnancy complications such as pre-eclampsia (PE) and intrauterine growth restriction (IUGR) are associated with structural and functional changes in the placenta. Different elastography techniques with an ability to assess the mechanical properties of tissue can identify and monitor the pathological state of the placenta. Currently available elastography techniques have been used with promising results to detect placenta abnormalities; however, limitations include inadequate measurement depth and safety concerns from high negative pressure pulses. Previously, we described a shear wave absolute vibro-elastography (SWAVE) method by applying external low-frequency mechanical vibrations to generate shear waves and studied 61 post-delivery clinically normal placentas to explore the feasibility of SWAVE for placental assessment and establish a measurement baseline. This next phase of the study, namely, SWAVE 2.0, improves the previous system and elasticity reconstruction by incorporating a multi-frequency acquisition system and using a 3-D local frequency estimation (LFE) method. Compared with its 2-D counterpart, the proposed system using 3-D LFE was found to reduce the bias and variance in elasticity measurements in tissue-mimicking phantoms. In the aim of investigating the potential of improved SWAVE 2.0 measurements to identify placental abnormalities, we studied 46 post-delivery placentas, including 26 diseased (16 IUGR and 10 PE) and 20 normal control placentas. By use of a 3.33-MHz motorized curved-array transducer, multi-frequency (80,100 and 120 Hz) elasticity measures were obtained with 3-D LFE, and both IUGR (15.30 ± 2.96 kPa, p = 3.35e–5) and PE (12.33 ± 4.88 kPa, p = 0.017) placentas were found to be significantly stiffer compared with the control placentas (8.32 ± 3.67 kPa). A linear discriminant analysis (LDA) classifier was able to classify between healthy and diseased placentas with a sensitivity, specificity and accuracy of 87%, 78% and 83% and an area under the receiver operating curve of 0.90 (95% confidence interval: 0.8–0.99). Further, the pregnancy outcome in terms of neonatal intensive care unit admission was predicted with a sensitivity, specificity and accuracy of 70%, 71%, 71%, respectively, and area under the receiver operating curve of 0.78 (confidence interval: 0.62–0.93). A viscoelastic characterization of placentas using a fractional rheological model revealed that the viscosity measures in terms of viscosity parameter n were significantly higher in IUGR (2.3 ± 0.21) and PE (2.11 ± 0.52) placentas than in normal placentas (1.45 ± 0.65). This work illustrates the potential relevance of elasticity and viscosity imaging using SWAVE 2.0 as a non-invasive technology for detection of placental abnormalities and the prediction of pregnancy outcomes.
... Albayraket et al. analyzed the placenta and found that PSR has some promise in predicting PTD. This is because the fat-to-strain placenta ratio can be used to indicate PTD [82]. Tolunay et al. conducted a prospective study of threatened preterm labor (TPL) (n = 108) and measured PSR values. ...
Article
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Changes in tissue stiffness by physiological or pathological factors in tissue structure are identified earlier than their clinical features. Pathological processes such as uterine fibrosis, adenomyosis, endometrial lesions, infertility, and premature birth can manifest as tissue elasticity changes. In clinical settings, elastography techniques based on ultrasonography, optical coherence tomography, and magnetic resonance imaging are widely used for noninvasive measurement of mechanical properties in patients, providing valuable tool and information for diagnosis and treatment. Ultrasound elastography (USE) plays a critical role in obstetrics and gynecology clinical work because of its simplicity, non-invasiveness, and repeatability. This article reviews the recent progress of USE in uterine tumor diagnosis (especially early diagnosis and treatment effect evaluation), prediction of preterm birth, and intrauterine insemination. We believe that USE, especially shear wave elastography, may serve as a potential means to assess tissue stiffness, thereby improving the diagnosis and treatment of adenomyosis, fibroids, endometrial lesions, cervical cancer, and precise management of preterm birth and intrauterine insemination monitoring.
... The rectus abdominis muscle and the subcutaneous tissue were used as reference points for the stiffness coefficients. In the case of the second factor, its value measured in the second trimester of pregnancy can be effectively used as a marker of preterm labor [20]. Metalloproteinases (MMPs) are proteolytic enzymes that contain a zinc ion in the catalytic center. ...
Article
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Preterm birth (PTB) is the leading cause of perinatal morbidity and mortality. Its etiopathology is multifactorial; therefore, many of the tests contain the assessment of the biochemical factors and ultrasound evaluation of the cervix in patients at risk of preterm delivery. The study aimed at evaluating the socioeconomic data, ultrasound examinations with elastography, plasma concentrations of MMP-8 and MMP-9 metalloproteinases, and vaginal secretions in the control group as well as patients with threatened preterm delivery (high-risk patients). The study included 88 patients hospitalized in the Department of Obstetrics and Pregnancy Pathology, SPSK 1, in Lublin. Patients were qualified to the study group (50) with a transvaginal ultrasonography of cervical length (CL) ≤ 25 mm. The control group (38) were patients with a physiological course of pregnancy with CL > 25 mm. In the study group, the median length of the cervix was 17.49 mm. Elastographic parameters: strain and ratio were 0.20 and 0.83. In the control group, the median length of the cervix was 34.73 mm, while the strain and ratio were 0.20 and 1.23. In the study group, the concentration of MMP-8 in the serum and secretions of the cervix was on average 74.17 and 155.46 ng/mL, but in the control group, it was significantly lower, on average 58.49 and 94.19 ng/mL. The concentration of MMP-9 in both groups was on the same level. Evaluation of the cervical length and measurement of MMP-8 concentration are the methods of predicting preterm delivery in high-risk patients. The use of static elastography did not meet the criteria of a PTB marker.
... Placental strain ratio, when measured with real-time sonoelastography, was found negatively correlated with gestational age at birth and it was suggested to be an effective predictor for PB [45]. ...
Article
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There is not a single or combined screening method for preterm birth with high sensitivity which will truly identify the women at risk for preterm birth while also with high specificity to prevent unnecessary interventions and high treatment costs. Measurement of cervical length is the most cost-effective method that is used in clinical practice. Bedside tests have also been developed for detecting markers like fetal fibronectin, insulin-like growth factor binding protein-1 (IGFBP-1), interleukin-6, and placental alpha-macroglobulin-1. Taking the maternal history, health condition, and sociodemographical factors into consideration is recommended. Ultrasound markers apart from cervical length measurements as uterocervical angle and placental strain ratio are studied. Investigations on metabolomics, proteomics, and microRNA profiling have brought a new aspect on this subject. Maybe in the future, with clear identification of women at true risk for preterm birth, development of more effective preventive strategies will not be unfeasible.
Article
This study aimed to investigate the predictive value of real-time shear wave elastography (SWE) for spontaneous preterm birth (SPB). This study prospectively selected 175 women with singleton pregnancies at 16 to 36 weeks of gestation. Cervical length (CL) and uterocervical angle (UCA) were measured using transvaginal ultrasonography. Real-time shear wave elastography was used to measure Young’s modulus values, including the average Young’s modulus (Emean) and the maximum Young’s modulus (Emax) at 4 points: point A on the inner lip of the cervical os, point B on the outer lip of the cervical os, point C on the inner lip of the external os, and point D on the outer lip of the external os. Receiver operating characteristic (ROC) curve analysis was performed to compare the accuracy of Young’s modulus values at the 4 points, CL, and UCA in predicting SPB. Significant variables were used to construct a binary logistic regression model to predict the multifactorial predictive value of SPB, which was evaluated using an ROC curve. A total 176 valid cases, including 160 full-term pregnancies and 16 SPB, were included in this study. Receiver operating characteristic curve analysis revealed that Emean at point A, as well as Emean and Emax at point D, had a relatively high accuracy in diagnosing SPB, with area under the curve values of 0.704, 0.708, and 0.706, respectively followed by CL (0.670), SWE at point C (Emean 0.615, Emax 0.565), SWE at point B (Emean 0.577, Emax 0.584), and UCA (0.476). Binary logistic regression analysis showed that comorbidities during pregnancy (including diabetes mellitus, hypertension, cholestasis and thyroid dysfunction), CL, and Emean at point A were independent predictors of preterm birth. In addition, the AUC value of the logistic regression model’s ROC curve was 0.892 (95% CI: 0.804–0.981), with a sensitivity of 0.867, specificity of 0.792, and Youden’s index of 0.659, indicating that the regression model has good predictive ability for SPB. Real-time shear wave elastography showed a higher predictive value for SPB than CL and UCA. The SWE combined with CL and comorbidities during pregnancy model has a good predictive ability for SPB.
Article
Aim: We aimed to evaluate placental elasticity for the short-time prediction of delivery in cases of threatened preterm labor (TPL). Methods: We performed a prospective study with consented pregnant women diagnosed with TPL (24th to 34th gestational week). According to the birth time, the patients were grouped into two groups, whether the delivery happened in the following first week or not. We compared the placental strain ratio (PSR) values between these two groups. Results: A total of 108 pregnant women divided into two groups according to the delivery time were enrolled in our study. The pregnant women who had a delivery in 1 week after hospitalization have increased PSR values when compared to those who have not delivered within 1 week (P < 0.001). Multivariate logistic regression analysis showed that cervical length and PSR were significantly associated with delivery in 1 week after hospitalization. When the cervical length was entered as a covariate (control) variable, PSR was significantly associated with delivery time (B = 0.504, odds ratio: 1.655, 95% confidence interval: 1.339-2.045, P < 0.001). A PSR value of 4.04 had a sensitivity of 77.78% and a specificity of 87.04% in terms of short-time prediction of the delivery time, in the receiver-operator curves analysis to determine the cut-off point PSR value. Conclusion: Elastography may contribute to predict the delivery time in high-risk pregnants with TPL.
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In this study, a new model for predicting preterm delivery (PD) was proposed. The primary model was constructed using ten selected variables, as previously defined in seventeen different studies. The ability of the model to predict PD was evaluated using the combined measurement from these variables. Therefore, a prospective investigation was performed by enrolling 130 pregnant patients whose gestational ages varied from 17⁺⁰ to 28⁺⁶ weeks. The patients underwent epidemiological surveys and ultrasonographic measurements of their cervixes, and cervicovaginal fluid and serum were collected during a routine speculum examination performed by the managing gynecologist. The results showed eight significant variables were included in the present analysis, and combination of the positive variables indicated an increased probability of PD in pregnant patients. The accuracy for predicting PD were as follows: one positive – 42.9%; two positives – 75.0%; three positives – 81.8% and four positives – 100.0%. In particular, the combination of ≥2× positives had the best predictive value, with a relatively high sensitivity (82.6%), specificity (88.1%) and accuracy rate (79.2%), and was considered the cut-off point for predicting PD. In conclusion, the new model provides a useful reference for evaluating the risk of PD in clinical cases.
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Objective: Acute atherosis is characterized by subendothelial lipid-filled foam cells, fibrinoid necrosis and perivascular lymphocytic infiltration. This lesion is generally confined to non-transformed spiral arteries and is frequently observed in patients with preeclampsia. However, the frequency of acute atherosis in the great obstetrical syndromes is unknown. The purpose of this study was to determine the frequency and topographic distribution of acute atherosis in placentas and placental bed biopsy samples obtained from women with normal pregnancy and those affected by the “great obstetrical syndromes”. We also examined the relationship between acute atherosis and pregnancy outcome in patients with preeclampsia. Material and methods: A retrospective cohort study of pregnant women who delivered between July 1998 and July 2014 at Hutzel Women’s Hospital/Detroit Medical Center was conducted to examine 16 345 placentas. Patients were classified into the following groups: (1) uncomplicated pregnancy; (2) spontaneous preterm labor (sPTL) and preterm prelabor rupture of membranes (PPROM); (3) preeclampsia; (4) gestational hypertension; (5) small-for-gestational age (SGA); (6) chronic hypertension; (5) fetal death; (6) spontaneous abortion and (7) others. A subset of patients had placental bed biopsy. The incidence of acute atherosis was compared among the different groups. Results: (1) The prevalence of acute atherosis in uncomplicated pregnancies was 0.4% (29/6961) based upon examination of nearly 7000 placentas; (2) the frequency of acute atherosis was 10.2% (181/1779) in preeclampsia, 9% (26/292) in fetal death, 2.5% (3/120) in midtrimester spontaneous abortion, 1.7% (22/1,298) in SGA neonates and 1.2% (23/1,841) in sPTL and PPROM; (3) among patients with preeclampsia, those with acute atherosis than in those without the lesion had significantly more severe disease, earlier onset, and a greater frequency of SGA neonates (p < 0.05 all) and (4) the lesion was more frequently observed in the decidua (parietalis or basalis) than in the decidual segment of the spiral arteries in patients with placental bed biopsies. Conclusions: Acute atherosis is rare in normal pregnancy, and occurs more frequently in patients with pregnancy complications, including preeclampsia, sPTL, preterm PROM, midtrimester spontaneous abortion, fetal death and SGA.
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Purpose The aim of this study is to determine if the Strain elastography (SE) of the placenta measured in the second trimester differs between normal pregnancies and pregnancies complicated by preeclampsia (PE). Methods 219 singleton pregnancies who had routine anomaly scanning between the 20th and 23rd weeks of gestation were included in this observational study. Women with either posterior placentations (n = 63) or other obstetric pathologies (n = 12) were excluded from the study, leaving 144 pregnant women for the evaluation of strain ratio with SE. One hundred and one women with normal pregnancies and normal deliveries without any perinatal complications formed Group A. Twenty-eight patients who were clinically diagnosed with early onset PE before anomaly scanning formed Group B. Fifteen normotensive pregnant women with either mild proteinuria, and past history of preeclampsia during their previous pregnancies formed Group C. The strain ratios were compared between the groups. Results The strain ratio of Group B was significantly higher than those of Group A and Group C (p
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Objective: Acute atherosis is a lesion of the spiral arteries characterized by fibrinoid necrosis of the vessel wall, an accumulation of fat-containing macrophages, and a mononuclear perivascular infiltrate, which can be found in patients with preeclampsia, fetal death, small-for-gestational age, spontaneous preterm labor/premature prelabor rupture of membrane, and spontaneous mid-trimester abortion. This lesion is thought to decrease blood flow to the intervillous space which may lead to other vascular lesions of the placenta. The objective of this study was to test whether there is an association between acute atherosis and placental lesions that are consistent with maternal vascular underperfusion (MVU), amniotic fluid infection (AFI), fetal vascular thrombo-occlusive disease (FVTOD) or chronic inflammation. Material and methods: A retrospective cohort study of pregnant women who delivered between July 1998 and July 2014 at Hutzel Women's Hospital/Detroit Medical Center was conducted examine 16 457 placentas. The frequency of placenta lesions (diagnosed using the criteria of the Perinatal Section of the Society for Pediatric Pathology) was compared between pregnancies with and without acute atherosis. Results: Among 16 457 women who were enrolled, 10.2% (1671/16 457) were excluded, leaving 14 786 women who contributed data for analysis. Among them, the prevalence of acute atherosis was 2.2% (326/14 786). Women with acute atherosis were more than six times as likely as those without to have placental lesions consistent with maternal underperfusion (adjusted odds ratio - aOR: 6.7; 95% CI 5.2-8.6). To a lesser degree, acute atherosis was also associated with greater risks of having either lesions consistent with FVTOD (aOR 1.7; 95% CI 1.2-2.3) or chronic chorioamnionitis (aOR 1.9; 95% CI 1.3-3), but not with other chronic inflammatory lesions, after adjusting for gestational age at delivery. In contrast, women with acute atherosis were 60% less likely to have lesions consistent with AFI, adjusting for gestational age at delivery (aOR 0.4; 95% CI 0.3-0.5). Conclusions: Acute atherosis is associated with increased risks of having placental lesions consistent with MVU, and to a lesser extent, chronic chorioamnionitis and those consistent with FVTOD.
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Preterm birth is associated with 5 to 18% of pregnancies and is a leading cause of infant morbidity and mortality. Spontaneous preterm labor, a syndrome caused by multiple pathologic processes, leads to 70% of preterm births. The prevention and the treatment of preterm labor have been long-standing challenges. We summarize the current understanding of the mechanisms of disease implicated in this condition and review advances relevant to intra-amniotic infection, decidual senescence, and breakdown of maternal-fetal tolerance. The success of progestogen treatment to prevent preterm birth in a subset of patients at risk is a cause for optimism. Solving the mystery of preterm labor, which compromises the health of future generations, is a formidable scientific challenge worthy of investment.
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Objective: To determine if there is an association between cervical strain, evaluated using ultrasound elastography, and spontaneous preterm delivery (sPTD) <37 weeks of gestation. Methods: One hundred and eighty nine (189) women at 16-24 weeks of gestation were evaluated. Ultrasound elastography was used to estimate cervical strain in three anatomical planes: one mid-sagittal in the same plane used for cervical length measurement, and two cross sectional images: one at the level of the internal cervical os, and the other at the level of the external cervical os. In each plane, two regions of interest (endocervix and entire cervix) were examined; a total of six regions of interest were evaluated. Results: The prevalence of sPTD was 11% (21/189). Strain values from each of the six cervical regions correlated weakly with cervical length (from r=-0.24, P<0.001 to r=-0.03, P=0.69). Strain measurements obtained in a cross sectional view of the internal cervical os were significantly associated with sPTD. Women with strain values ≤25th centile in the endocervical canal (0.19) and in the entire cervix (0.14) were 80% less likely to have a sPTD than women with strain values >25th centile [endocervical: odds ratio (OR) 0.2; 95% confidence interval (CI), 0.03-0.96; entire cervix: OR 0.17; 95% CI, 0.03-0.9]. Additional adjustment for gestational age, race, smoking status, parity, maternal age, pre-pregnancy body mass index, and previous preterm delivery did not appreciably alter the magnitude or statistical significance of these associations. Strain values obtained from the external cervical os and from the sagittal view were not associated with sPTD. Conclusion: Low strain values in the internal cervical os were associated with a significantly lower risk of spontaneous preterm delivery <37 weeks of gestation.
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Abstract AIM: To determine the utility of elastosonography combined to cervical length measurement to predict preterm labor. One hundred twenty seven women with pregnancies between 21 to 36 weeks of gestation without any risk factor for preterm labor were included in the study. All subjects underwent sonographic evaluation including fetal biometry, cervical length measurement and elastosonography of uterine myometrium. Subcutaneous tissue was the reference point for elastosonography evaluation. Tissue strain ratio values were obtained from all the patients. Cervical length was a significant predictor for preterm delivery (AUC=0.958, P < 0.001). Optimal cut off value was obtained at 30 mm with 92% sensitivity and 81% specificity. Elastosonographic strain ratio was also significant predictor for preterm delivery (AUC=0.827, P < 0.001). Optimal cut off value was obtained at 4.7 with 79% sensitivity and 91% specificity. In linear regression analysis strain ratio (R2=0.61, beta=0.171, P=0.03) and cervical length (R2=0.61, beta=-0.516, P < 0.001) were significantly associated with preterm delivery. Cervical length < 30 mm [39.1(95 CI, 6.6-231.5, P < 0.001)] and strain ratio > 4.7 [24.5(95 CI, 4.1-146.5, P<0.001)] were the risk factors for preterm delivery. Elastosonographic evaluation of uterine myometrium was found to be significantly correlated with cervical length but cervical length measurement is a better predictor for preterm labor than elastosonography.
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To prospectively estimate the accuracy of sonoelastography in the differentiation of benign and metastatic cervical lymph nodes (LNs) in patients suspected of having thyroid or hypopharyngeal cancer, with histologic nodal findings as the reference standard. The study protocol was approved by the hospital review board; each patient gave written informed consent. One hundred forty-one peripheral neck LNs (60 metastatic, 81 metastasis free) in 43 consecutive patients (22 men, 21 women; mean age, 58 years +/- 13 [standard deviation]) were examined. Patients referred for surgical treatment of suspected thyroid or hypopharyngeal cancer were examined with gray-scale ultrasonography (US), power Doppler US, and sonoelastography. At gray-scale and power Doppler US, the following LN characteristics were evaluated: short-axis diameter, short-to-long-axis diameter ratio, echogenicity, calcifications, and vascularity. A four-point rating scale was used to evaluate the US elastograms for LN visibility, relative brightness, margin regularity, and margin definition. In addition, strains of LN and surrounding neck muscles were measured on elastograms, and the muscle-to-LN strain ratio--that is, the strain index-was calculated. The diagnostic potential of the examined criteria for metastatic involvement was evaluated with univariate analysis and multivariate generalized estimating equation (GEE) regression. P < .05 indicated statistical significance. A strain index greater than 1.5 had high utility in metastatic LN classification, with 98% specificity, 85% sensitivity, and 92% overall accuracy. These results were significantly better than those obtained by using the best gray-scale criterion--that is, a short-to-long-axis diameter ratio greater than 0.5-which had 81% specificity, 75% sensitivity, and 79% overall accuracy. Sonoelastography had high accuracy (92%) in the differentiation of benign and metastatic cervical LNs in patients suspected of having thyroid or hypopharyngeal cancer.
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To prospectively evaluate the sensitivity and specificity of ultrasonographic (US) strain imaging for distinguishing between benign and malignant solid breast masses, with biopsy results as the reference standard. The study was institutional review board approved and HIPAA compliant. Informed consent was obtained from all participating patients. US strain imaging of 403 breast masses was performed. The 50 malignant and 48 benign lesions (in patients aged 19-83 years; mean age, 49 years +/- 17 [standard deviation]) with the highest quality were selected for the reader study. Three observers blinded to the pathologic outcomes first described the B-mode image findings by using US Breast Imaging Reporting and Data System descriptors and derived a probability of malignancy. They then updated the probability by assessing strain images. Receiver operating characteristic (ROC) curves were constructed by using these probabilities. Areas under the ROC curve, sensitivities, and specificities were calculated and compared. Interobserver variability and the correlation between automated and subjective image quality assessment were analyzed. The average area under the ROC curve for all three readers after US strain imaging (0.903) was greater than that after B-mode US alone (0.876, P = .014). With use of a 2% probability of malignancy threshold, strain imaging-as compared with B-mode US alone-had improved average specificity (0.257 vs 0.132, P < .001) and high sensitivity (0.993 vs 0.987, P > .99). Significant interobserver variability was observed (P < .001). The ability to assess strain image quality appeared to correlate with the highest observer performance. US strain imaging can facilitate improved classification of benign and malignant breast masses. However, interobserver variability and image quality influence observer performance.
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The velocities of the lateral shear waves (Vs; m s(-1)) generated by an acoustic radiation force impulse (ARFI) correlate with Young's modulus. Therefore, ARFI can be used as a new method to evaluate tissue elasticity. The aim of this study was to investigate the safety of ARFI imaging and the differences in placental elasticity in complicated cases. The study population included 115 patients between 26 and 41 weeks gestation, who were divided into three groups, namely normal, fetal growth restriction (FGR) and pregnancy-induced hypertension (PIH). After delivery, the Vs values of the placenta were measured ex vivo. After ARFI imaging, microscopic examination was performed, the Vs values were compared among the three groups and the relationship between the Vs values and neonatal birthweight Z-score was investigated. No histological changes were noted even after ARFI imaging. The Vs values in the FGR group were significantly higher than those in the normal group (1.94 ± 0.74 and 1.31 ± 0.35 m s(-1), respectively; p < 0.05). The Vs values demonstrated a significant negative correlation with the Z-score. Moreover, as the Z-score became lower, the Vs values became higher in the range of Z-scores under -0.5 standard deviation (SD). We speculate that the increased Vs values in the FGR group may have been caused by histological changes, and that a more severe FGR might result in increased Vs values. ARFI imaging was observed to have no apparent histological damage to the placental tissue. Ex vivo placentas from the FGR group were significantly more firm. Moreover, Vs values and Z-scores of birthweight had a significant negative correlation. Additional investigations are needed about the utility of this method for the evaluation of placental function in vivo.
Article
Objectives: The purpose of this study was to evaluate the clinical value of strain elastography for detection of the lesion extent of large-scar endometriosis and compare it to conventional sonography and magnetic resonance imaging (MRI). Methods: Eight patients suspected of having large-scar endometriosis underwent transabdominal sonography, strain elastography, and MRI. The mass was located and assessed for its size, imaging appearance, and, especially, widest boundary and vertical extent. After wide surgical excision and pathologic diagnosis, lesions in the central area shown on conventional sonography and the extended area shown on strain elastography underwent immunohistochemical examination. Results: Nodules were always deep in the subcutaneous plane, in contact with the fascia or muscle. Horizontally, the mean lesion size shown on conventional sonography was mainly consistent with the size on MRI in all cases, but it was obviously smaller on sonography than on strain elastography in 7 cases. Vertically, the lesion depth was mainly consistent with the depth on MRI in 7 cases, but it was more infiltrative on strain elastography in 6 cases. The vertical and horizontal infiltration scales of the postoperative specimens were consistent with strain elastography in all cases. All 8 patients showed strong collagen type I expression in the central area of the lesions; 6 patients showed strong collagen type I expression and the other 2 showed moderate expression in the extended area. Conclusions: Strain elastography can elevate the diagnostic accuracy of large-scar endometriosis, the extent of which may be evaluated insufficiently by transabdominal sonography and MRI.
Article
Objectives: The aim of this study was to evaluate the value of imaging analysis of cervical elastography to predict successful induction of labor in nulliparous women at term. Methods: Successful labor induction was defined as onset of active labor within 9 hours or delivery within 24 hours. The Bishop score, cervical length, and cervical elastographic parameters, including cervical area, mean elastographic index, and cervical hard area, were measured and analyzed by the image analyzer. Results: The areas under the curves for the cervical length, cervical area, Bishop score, mean elastographic index, and cervical hard area were 0.63, 0.64, 0.47, 0.68, and 0.70, respectively, for onset of active labor within 9 hours and 0.70, 0.68, 0.63, 0.71, and 0.76 for delivery within 24 hours. The combination of cervical length and elastographic data was more predictable for successful labor induction (P < .05). Conclusions: Imaging analysis of cervical elastography is available to predict successful induction of labor.
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Ultrasonography has been widely used for diagnosis since it was first introduced in clinical practice in the 1970's. Since then, new ultrasound modalities have been developed, such as Doppler imaging, which provides new information for diagnosis. Elastography was developed in the 1990's to map tissue stiffness, and reproduces/replaces the palpation performed by clinicians. In this paper, we introduce the principles of elastography and give a technical summary for the main elastography techniques: from quasi-static methods that require a static compression of the tissue to dynamic methods that uses the propagation of mechanical waves in the body. Several dynamic methods are discussed: vibro-acoustography, Acoustic Radiation Force Impulsion (ARFI), transient elastography, shear wave imaging, etc. This paper aims to help the reader at understanding the differences between the different methods of this promising imaging modality that may become a significant tool in medical imaging.
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To explore the clinical values in detecting the placental elastic modulus using real-time quantitative shear wave elasticity imaging. A total of 30 women in the late pregnancy stage without complications and having normal, single pregnancies, as well as normal fetal growth, amniotic fluid index, and anterior placenta were selected. A real-time elasticity imaging shear wave ultrasonic diagnostic apparatus was used to randomly select regions of interest at the central and edge of the placenta. The elastography imaging mode was launched to measure the elasticity of the elastic modulus of these placental parts. A total of 15 measured values were obtained at the placental center and edge for each pregnancy case. Umbilical artery and uterine artery pulsatility index (PI) values for 18 cases were also randomly measured. The average value of 30 placental edges of the elastic modulus (n = 15) was (7.60 +/- 1.71) kPa. The average value of the 30 placental central elastic modulus (n = 15 ) was (7.84 +/- 1.68) kPa. No significant difference was observed between placenta central and edge elastic modulus. The PI mean value of umbilical artery in 18 cases was 0.94, whereas the average PI values of the uterine artery was 0.83. No linear correlation was found among the elastic modulus, the placental uterine artery PI values, and the umbilical artery PI values (p > 0.05). No difference between the placental center of normal pregnancies and the edge of the elastic modulus was detected. The elastic modulus of the placenta could be obtained in the best position. The placenta varied greatly between elastic modulus. No correlation was found between the placental elastic modulus, the uterine artery, and umbilical artery PI values. Real-time shear wave elasticity imaging technology can provide morphological evidence of placental function, which may emerge as a new clinical assessment approach.
Article
Objective: Pregnancy complications such as intra-amniotic infection, preeclampsia, and fetal intrauterine growth restriction (IUGR) account for most cases of preterm birth (PTB), but many spontaneous PTB cases do not have a clear etiology. We hypothesize that placental insufficiency may be a potential cause of idiopathic PTB. Methods: Secondary analysis of 82 placental samples from women with PTB obtained from a multicenter trial of repeat versus single antenatal corticosteroids. Samples were centrally reviewed by a single placental pathologist masked to clinical outcomes. The histopathologic criterion for infection was the presence of acute chorioamnionitis defined as neutrophils marginating into the chorionic plate. Placental villous hypermaturation (PVH) was defined as a predominance of terminal villi (similar to term placenta) with extensive syncytial knotting. Idiopathic PTB comprised a group without another known etiology such as preeclampsia, IUGR or infection. Results: Acute chorioamnionitis was observed in 33/82 (40%) cases. Other known causes of PTB were reported in 18/82 (22%). The remaining 31/82 (38%) were idiopathic. The frequency of PVH in idiopathic PTB (26/31 = 84%) was similar to cases with IUGR or preeclampsia (16/18 = 89%), but significantly more common than PVH in the group with acute chorioamnionitis (10/33 = 30%) (p < 0.001). Conclusions: PVH, which is a histologic marker of relative placental insufficiency, is a common finding in idiopathic PTB.
Article
Increased uterine contractility at term and preterm results from activation and then stimulation of the myometrium. Activation can be provoked by mechanical stretch of the uterus and by an endocrine pathway resulting from increased activity of the fetal hypothalamic-pituitary-adrenal (HPA) axis. In fetal sheep, increased cortisol output during pregnancy regulates prostaglandin H synthase type 2 (PGHS2) expression in the placenta in an estrogen-independent manner, resulting in increased levels of PGE2 in the fetal circulation. Later increases in maternal uterine expresssion of PGHS2 require elevations of estrogen and lead to increased concentrations of PGF2α in the maternal circulation. Thus, regulation of PGHS2 at term is differentially controlled in fetal (trophoblast) and maternal (uterine epithelium) tissue. This difference may reflect expression of the glucocorticoid receptor (GR), but not estrogen receptor (ER), in placental trophoblast cells. In women, cortisol also contributes to increased PG production in fetal tissues through upregulation of PGHS2 (amnion and chorion) and downregulation of 15-OH PG dehydrogenase (chorion trophoblasts). The effect of cortisol on chorion expression of PGDH reverses a tonic stimulatory effect of progesterone, potentially through a paracrine or autocrine action. We have interpreted this interaction as a reflection of “progesterone withdrawal” in the primate, in relation to birth. Other agents, such as proinflammatory cytokines, similarly upregulate PGHS2 and decrease expression of PGDH, indicating the presence of several mechanisms by which labor at term or preterm may be initiated. These different mechanisms need to be considered in the development of strategies for the detection and management of the patient in preterm labor.
Article
Measurement of muscle hardness is important for objective evaluation of the muscle condition. Muscle hardness may be related to muscle size, but this relationship has not yet been examined. To examine the relationship between the size and hardness of the medial gastrocnemius muscle (MG) at different ankle joint angles. Twelve young male subjects comprised the present study. Muscle thickness of the right MG (MT(MG)) was measured by ultrasonography as an index of muscle size. The MT(MG) was determined at 30% of the lower leg length from the popliteal crease to the lateral malleolus. At the same site, muscle hardness of the right MG (MH(MG)) was measured with ultrasound real-time tissue elastography. Both measurements were taken while each subject was instructed to lie in a prone position on a test bench. The right ankle was secured to a handmade apparatus by a non-elastic belt, with the hip and knee joints fully extended and the ankle positioned at +30°, 0° and -20° (0°: neutral position, positive values indicating plantar flexion). There were no significant differences in the MT(MG) among the ankle joint angles whereas the MH(MG) significantly increased as the ankle was moved from plantar flexion to dorsiflexion. As a result, there was a difference in the MT(MG)-MH(MG) relationship between the angles. The MT(MG) significantly correlated with the MH(MG) only at +30° (r = 0.635, P < 0.05) where passive torque around the ankle has been shown to be near zero in previous studies. The hardness of the relaxed MG with no passive tension appears to depend on its size.
Article
Elastography has emerged as a useful adjunct tool for ultrasound diagnosis. Elastograms are images of tissue stiffness and may be in color, grayscale, or a combination of the two. The first and most common application of elastography is for the diagnosis of breast lesions where studies have shown an area under the receiver operating characteristic curve of 0.88 to 0.95 for distinguishing cancer from benign lesions. The technique is also useful for the diagnosis of complex cysts, although different scanners may vary in how they display such lesions. Recent advances in elastography include quantification using strain ratios, acoustic radiation force impulse imaging, and shear wave velocity estimation. These are useful not only for characterizing focal masses but also for diagnosing diffuse organ diseases such as liver cirrhosis. Other near term potential applications for elastography include characterization of thyroid nodules and lymph node evaluation for metastatic disease. Prostate cancer detection is also a potential application, but obtaining high-quality elastograms may be difficult. This area is evolving. Other promising applications include atheromatous plaque and arterial wall evaluation, venous thrombus evaluation, graft rejection, and monitoring of tumor ablation therapy. When contemplating the acquisition of a system with elastography in this rapidly evolving field, a clear picture of the manufacturer's plans for future upgrades (including quantification) should be obtained.
Article
To assess the feasibility of ultrasound real-time tissue elastography (RTE) for measuring exercise-induced changes in muscle hardness and to compare the findings of RTE with those of a tissue hardness meter for semi-quantitative assessment of the hardness of exercised muscles. Nine male participants performed an arm-curl exercise. RTE measurements were performed by manually applying repetitive compression with the transducer on the scan position before exercise, immediately after exercise, and at 30 min after exercise; strain ratios between muscle and a reference material (hydrogel) were calculated (muscle strain/material strain). A tissue hardness meter was also used to evaluate muscle hardness. The intraclass correlation coefficients (ICCs) for the three repeated measurements at each measurement time were calculated to evaluate the intra-observer reproducibility of each technique. Immediately after exercise, the strain ratio and the value obtained using the tissue hardness meter significantly decreased (from 1.65 to 1.35) and increased (from 51.8 to 54.3), respectively. Both parameters returned to their pre-exercise value 30 min after exercise. The ICCs of the RTE (and the ICCs of the muscle hardness meter) were 0.971 (0.816) before exercise, 0.939 (0.776) immediately after exercise, and 0.959 (0.882) at 30 min after exercise. Similar to the muscle hardness meter, RTE revealed the exercise-induced changes of muscle hardness semi-quantitatively. The intra-observer reproducibility of RTE was very high at each measurement time. These findings suggest that RTE is a clinically useful technique for assessing hardness of specific exercised muscles.
Article
Muscle hardening, including delayed onset muscle soreness, can be found after vigorous exercise. Some techniques for measuring muscle hardness have been proposed. Freehand ultrasound (US) elastography has been developed and applied to breast imaging. To evaluate the feasibility of US elastography for investigating changes in muscle hardness after eccentric exercise of the elbow flexor muscles. Six healthy male volunteers performed eccentric contractions of the elbow flexor muscles of their non-dominant arms. US elastography was performed by using 14-6 MHz linear array transducer combined with a stabilizer and a gel pack of reference agent. Color-coded elasticity images and the relative strain ratio of the biceps brachii muscle to the reference were obtained. To verify the US elastography measurements, a commercially available durometer was also employed. Both measurements were performed before, immediately after, and 1-4 days after exercise. The mean scores of strain ratios of the US elastography and durometer measurements were examined using repeated-measures ANOVA. US elastography demonstrated significant muscle hardening and recovery after exercise (P<0.01). Muscle hardness increased up immediately after the exercise and continued to increase, peaking on day 2 post-exercise, and then decreased until day 4. The durometer indicated similar changes to US elastography. The control arms did not demonstrate any significant change. US elastography is feasible to measure muscle hardness and to produce a two-dimensional hardness map of the muscle.
Article
Acoustic radiation force impulse (ARFI) is a new technology integrated into conventional B-mode ultrasonography. ARFI is used to evaluate tissue stiffness in several organs, but this method has not been applied for liver fibrosis. The aim of this study was to determine whether ARFI elastography is useful for the evaluation of liver fibrosis. This study enrolled 55 consecutive patients with chronic liver disease who underwent a liver biopsy for histological assessment of liver fibrosis by the Metavir scoring system. Liver stiffness of the 55 patients and 25 healthy volunteers was evaluated by ARFI elastography and was expressed as the shear wave velocity. Cut-off values were determined using receiver-operating characteristic (ROC) curves. Histological liver fibrosis was evaluated by Metavir scoring; F0: six cases, F1: 14 cases, F2: nine cases, F3: nine cases and F4: 17 cases. Liver stiffness determined by ARFI elastography was correlated with histological liver fibrosis (P<0.0001). The areas under the ROC curves were 0.94 (95% confidence intervals, 0.87-0.99) for F2-F4, 0.94 (0.88-0.99) for F3-F4 and 0.96 (0.91-1.01) for F4. The cut-off values of the shear wave velocity were as follows: >1.34 m/s for F2-F4 (sensitivity 91.4%, specificity 80%); >1.44 m/s for F3-F4 (sensitivity 96.2%, specificity 79.3%); and >1.80 m/s for F4 (sensitivity 94.1%, specificity 86.8%). Ultrasonic ARFI elastography is a novel, non-invasive and reliable method for the assessment of liver fibrosis in patients with chronic liver disease.
Article
The purpose of this study was to evaluate the diagnostic utility of real-time ultrasound elastography in differentiating benign from malignant thyroid nodules. A total of 90 consecutive patients with thyroid nodules who were referred for surgical treatment were examined in this prospective study. One hundred forty-five nodules in these patients were examined by B-mode ultrasound, color Doppler ultrasound, and ultrasound elastography. The final diagnosis was obtained from histologic findings. Tissue stiffness on ultrasound elastography was scored from 1 (low stiffness over the entire nodule) to 6 (high stiffness over the entire nodule and surrounding tissue). On real-time ultrasound elastography, 86 of 96 benign nodules (90%) had a score of 1 to 3, whereas 43 of 49 malignant nodules (88%) had a score of 4 to 6 (P <.001), with sensitivity of 88%, specificity of 90%, a positive predictive value of 81%, and a negative predictive value of 93%. The predictivity of ultrasound elastographic measurement was independent of the nodule size. High sensitivity (88%) and specificity (93%) were also observed in 68 nodules that had a greatest diameter of 1 cm or less. Real-time ultrasound elastography is a promising imaging technique that is useful in the differential diagnosis of thyroid cancer.
Article
Ultrasound (US) elasticity imaging is an extension of the ancient art of palpation and of earlier US methods for viewing tissue stiffness such as echopalpation. Elasticity images consist of either an image of strain in response to force or an image of estimated elastic modulus. There are 3 main types of US elasticity imaging: elastography that tracks tissue movement during compression to obtain an estimate of strain, sonoelastography that uses color Doppler to generate an image of tissue movement in response to external vibrations, and tracking of shear wave propagation through tissue to obtain the elastic modulus. Other modalities may be used for elasticity imaging, the most powerful being magnetic resonance elastography. With 4 commercial US scanners already offering elastography and more to follow, US-based methods may be the most widely used for the near future. Elasticity imaging is possible for nearly every tissue. Breast mass elastography has potential for enhancing the specificity of US and mammography for cancer detection. Lesions in the thyroid, prostate gland, pancreas, and lymph nodes have been successfully imaged using elastography. Evaluation of diffuse disease including cirrhosis and transplant rejection is also possible using both imaging and nonimaging methods. Vascular imaging including myocardium, blood vessel wall, plaque, and venous thrombi has also shown great potential. Elasticity imaging may also be important in assessing the progress of ablation therapy. Recent work in assessing porous materials using elastography suggests that the technique may be useful in monitoring the severity of lymphedema.
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This paper is the first in a three-part series on preterm birth, which is the leading cause of perinatal morbidity and mortality in developed countries. Infants are born preterm at less than 37 weeks' gestational age after: (1) spontaneous labour with intact membranes, (2) preterm premature rupture of the membranes (PPROM), and (3) labour induction or caesarean delivery for maternal or fetal indications. The frequency of preterm births is about 12-13% in the USA and 5-9% in many other developed countries; however, the rate of preterm birth has increased in many locations, predominantly because of increasing indicated preterm births and preterm delivery of artificially conceived multiple pregnancies. Common reasons for indicated preterm births include pre-eclampsia or eclampsia, and intrauterine growth restriction. Births that follow spontaneous preterm labour and PPROM-together called spontaneous preterm births-are regarded as a syndrome resulting from multiple causes, including infection or inflammation, vascular disease, and uterine overdistension. Risk factors for spontaneous preterm births include a previous preterm birth, black race, periodontal disease, and low maternal body-mass index. A short cervical length and a raised cervical-vaginal fetal fibronectin concentration are the strongest predictors of spontaneous preterm birth.