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Gas–liquid flow mass transfer in a T-shape microreactor stimulated with 1.7 MHz ultrasound waves 被引量:4
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作者 Mona Akbari Masoud Rahimi Mahboubeh Faryadi 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2017年第9期1143-1152,共10页
This paper describes the application of ultrasound waves on hydrodynamics and mass transfer characteristics in the gas–liquid flow in a T-shape microreactor with a diameter of 800 μm. A 1.7 MHz piezoelectric transdu... This paper describes the application of ultrasound waves on hydrodynamics and mass transfer characteristics in the gas–liquid flow in a T-shape microreactor with a diameter of 800 μm. A 1.7 MHz piezoelectric transducer(PZT) was employed to induce the vibration in this microreactor. Liquid side volumetric mass transfer coefficients were measured by physical and chemical methods of CO_2 absorption into water and Na OH solution. The approach of absorption of CO_2 into a 1 mol·L^(-1) Na OH solution was used for analysis of interfacial areas. With the help of a photography system, the fluid flow patterns inside the microreactor were analyzed. The effects of superficial liquid velocity, initial concentration of Na OH, superficial CO_2 gas velocity and length of microreactor on the mass transfer rate were investigated. The comparison between sonicated and plain microreactors(microreactor with and without ultrasound) shows that the ultrasound wave irradiation has a significant effect on kLa and interfacial area at various operational conditions. For the microreactor length of 12 cm, ultrasound waves improved kLa and interfacial area about 21% and 22%, respectively. From this study, it can be concluded that ultrasound wave irradiation in microreactor has a great effect on the mass transfer rate. This study suggests a new enhancement technique to establish high interfacial area and kLa in microreactors. 展开更多
关键词 ultrasound waves MICROREACTOR Gas–liquid flow Mass transfer ABSORPTION
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Theoretical analysis of interaction between a particle and an oscillating bubble driven by ultrasound waves in liquid 被引量:2
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作者 武耀蓉 王成会 《Chinese Physics B》 SCIE EI CAS CSCD 2017年第11期279-286,共8页
A theoretical model is developed to describe the interaction of a particle and an oscillating bubble at arbitrary separation between them. The derivation of the model is based on the multipole expansion of the particl... A theoretical model is developed to describe the interaction of a particle and an oscillating bubble at arbitrary separation between them. The derivation of the model is based on the multipole expansion of the particle and bubble velocity potentials and the use of Lagrangian mechanics. The model consists of three coupled ordinary differential equations. One of them accounts for the pulsation of the bubble and the other two describe the translation of the bubble and particle in an infinite, incompressible liquid. The model here is accurate to order 1/d^10, where d is the distance between the centers of the particle and bubble. The effects of the size and density of the particle are investigated, namely, the interaction between the particle and bubble changes from repulsion to attraction with the increment of the particle density, and the increment of the particle size makes the interaction between the particle and bubble stronger. It is demonstrated that the driving frequency and acoustic pressure amplitude can affect the interaction of the particle and bubble. It is shown that the correct modeling of the translational dynamics of the bubble and particle at small separation distances requires terms accurate up to the tenth order. 展开更多
关键词 particle bubble ultrasound wave
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Quantitative Ultrasound Elastography of Breast: A Review and Update with Emphasis on Shear Wave Imaging (ARFI) 被引量:3
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作者 Duzgun Yildirim Özlem Akıncı Deniz Esin Tekcan 《Open Journal of Medical Imaging》 2021年第2期58-72,共15页
Elastography is a method which determines the stiffness of tissues with the help of ultrasound technology and exhibits more quantitative data according to palpation that made during physical examination. Elastography ... Elastography is a method which determines the stiffness of tissues with the help of ultrasound technology and exhibits more quantitative data according to palpation that made during physical examination. Elastography has relatively entered to routine use in the breast evaluation with imaging techniques. Although palpation has a very long history, elastography has been used since 1990s. Elastography is used as an adjunct to conventional gray scale ultrasound and can identify the stiffness of the tissues non-invasively. Today, it is used as two separate technological modalities: strain elastography and shear wave elastography. The aims of these modalities are to increase the sensitivity of the separation between malignant and benign lesions, reduce the unnecessary biopsy processes and to provide a more accurate Breast Imaging Reporting and Data System (BIRADS) categorization of the breast lesions. In this article, we aimed to review the clinical utilization and benefits of elastography in differantial diagnosis of breast lesions, BIRADS categorization, and biopsy decision making in the light of current literature. 展开更多
关键词 BREAST ELASTOGRAPHY Shear wave Elastography ultrasound
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Pulse wave Doppler ultrasound of testicular arteries and their relationship with semen characteristics in healthy bulls 被引量:1
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作者 Alessia Gloria Augusto Carluccio +3 位作者 Laura Wegher Domenico Robbe Claudio Valorz Alberto Contri 《Journal of Animal Science and Biotechnology》 SCIE CAS CSCD 2018年第2期319-325,共7页
Background: Semen evaluation is used to estimate the testicular function. In bulls, the spermatozoa present in the ejaculate are the result of a process that begun more than 2 mo earlier, bequeathing a delayed depicti... Background: Semen evaluation is used to estimate the testicular function. In bulls, the spermatozoa present in the ejaculate are the result of a process that begun more than 2 mo earlier, bequeathing a delayed depiction of the actual function of the testis. Since testis vascularization might be critical for the gonad function, selected pulse wave Doppler ultrasound parameters were assessed in this study, for instance the peak systolic velocity, the end diastolic velocity and the resistive index of the testicular artery along the spermatic cord, the marginal portion of the testicular artery and the intratesticular branches of the testicular artery both in healthy adult and young bulls.Correlations between these parameters and characteristics of semen that was collected numerous times, before and after the Doppler ultrasound examination.Results: The peak systolic velocity and the end diastolic velocity measured in the testicular artery along the spermatic cord(supratesticular artery – SA) were variable among the bulls and within individual bulls, likely due to the convoluted course of the vessel. The resistive index was found highly repeatable in the same bull. A reduction in the resistive index was found between the supratesticular artery and the marginal portion of the testicular artery(P < 0.01), and between the marginal portion of the testicular artery and the intratesticular branches of the testicular artery(P < 0.05). No differences were recorded for the pulse wave Doppler ultrasound parameters in young bulls compared with adults. A significant correlation was found between the resistive index of the marginal portion of the testicular artery and total sperm in the ejaculate(r = 0.516, P < 0.05), the immature sperm(r = 0.462, P < 0.05), the teratoid sperm(r = 0.375, P < 0.05), and the "Dag defect" sperm(r = 0.389, P < 0.05). Similarly, the resistive index of the intratesticular branches of the testicular artery were found correlated with the total sperm number in the ejaculate(r = 0.568, P < 0.05), the immature sperm(r = 0.523, P < 0.05), the teratoid sperm(r = 0.418, P < 0.05), and the "Dag defect" sperm(r = 0.341, P < 0.05).Conclusions: The data presented in this study suggest that the resistive index, measured at the marginal portion of the testicular artery, could be an easy-to-perform parameter to evaluate the spermatogenesis quality in young bulls and normal adults. 展开更多
关键词 BULL Pulse wave Doppler SPERM morphology TESTIS ultrasound
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Influence of mode conversions in the skull on transcranial focused ultrasound and temperature fields utilizing the wave field separation method: A numerical study
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作者 王祥达 林伟军 +1 位作者 苏畅 王秀明 《Chinese Physics B》 SCIE EI CAS CSCD 2018年第2期401-414,共14页
Transcranial focused ultrasound is a booming noninvasive therapy for brain stimuli. The Kelvin–Voigt equations are employed to calculate the sound field created by focusing a 256-element planar phased array through a... Transcranial focused ultrasound is a booming noninvasive therapy for brain stimuli. The Kelvin–Voigt equations are employed to calculate the sound field created by focusing a 256-element planar phased array through a monkey skull with the time-reversal method. Mode conversions between compressional and shear waves exist in the skull. Therefore, the wave field separation method is introduced to calculate the contributions of the two waves to the acoustic intensity and the heat source, respectively. The Pennes equation is used to depict the temperature field induced by ultrasound. Five computational models with the same incident angle of 0?and different distances from the focus for the skull and three computational models at different incident angles and the same distance from the focus for the skull are studied. Numerical results indicate that for all computational models, the acoustic intensity at the focus with mode conversions is 12.05%less than that without mode conversions on average. For the temperature rise, this percentage is 12.02%. Besides, an underestimation of both the acoustic intensity and the temperature rise in the skull tends to occur if mode conversions are ignored. However, if the incident angle exceeds 30?, the rules of the over-and under-estimation may be reversed. Moreover,shear waves contribute 20.54% of the acoustic intensity and 20.74% of the temperature rise in the skull on average for all computational models. The percentage of the temperature rise in the skull from shear waves declines with the increase of the duration of the ultrasound. 展开更多
关键词 transcranial focused ultrasound temperature rise mode conversion wave field separation
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Generation of Ultrasound Based on the Frequency Response Characteristics of the “Koss Pro Headphone” with R. David Case Sound Wave Files’—A Case Study
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作者 R. David Case D. Chuckravanen 《World Journal of Engineering and Technology》 2021年第2期374-383,共10页
The research aim of this work is to analyse the characteristics of R. David Case Sound waves that are posited to have positive effects on people suffering from tinnitus. Moreover, the participants who listened to thes... The research aim of this work is to analyse the characteristics of R. David Case Sound waves that are posited to have positive effects on people suffering from tinnitus. Moreover, the participants who listened to these sound wave files using specific headsets or headphones of the Koss models (ktx Pro, ksc-75) showed improved health condition such as alleviating tinnitus that they are suffering from. Therefore, these discoveries have encouraged R. David Case to pursue positively his journey into finding out what is special about those sounds when being listened specifically with Koss models. In this research, we focus mainly on the technical aspects of R. David Case sound signals which he has recorded. These specific sound waves were analysed using time domain, frequency domain as well as the effect of using the Koss Pro headphone frequency response characteristics applied to the sound. Results obtained from the analysis demonstrated that the generation of ultrasound c</span><span style="font-family:Verdana;">an</span><span style="font-family:Verdana;"> be the underlying reason for the treatment of the tin</span><span style="font-family:Verdana;">n</span><span style="font-family:Verdana;">itus. 展开更多
关键词 ultrasound TINNITUS David Case Sound wave File Frequency Analysis Healing
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高血压患者人迎脉Wave Intensity与脉象参数的相关性研究 被引量:4
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作者 郑星宇 骆杰伟 +5 位作者 魏世超 吴晶 叶振盛 陈玮吉 林宁 胡紫景 《世界中西医结合杂志》 2015年第12期1688-1692,共5页
目的探讨高血压患者人迎脉(颈总动脉)Wave Intensity(WI)各项参数与脉象仪参数的相关性。方法用ALOKA Prosoundα10彩色多普勒超声仪检测80例高血压病患者,获取右颈总动脉前向压缩波(W1)、前向膨胀波(W2)、低振幅负向波(NA)、僵硬度(β... 目的探讨高血压患者人迎脉(颈总动脉)Wave Intensity(WI)各项参数与脉象仪参数的相关性。方法用ALOKA Prosoundα10彩色多普勒超声仪检测80例高血压病患者,获取右颈总动脉前向压缩波(W1)、前向膨胀波(W2)、低振幅负向波(NA)、僵硬度(β)、β值推导的脉搏波传导速度(PWVβ)、顺应性(AC)、弹性模量(Ep)等数据,应用DDMX-100脉象仪检测右侧寸口脉关部,收集主波高度(h1)、潮波高度(h3)、降中峡高度(h4)、重搏波高度(h5)、脉图收缩期面积(As)、脉图舒张期面积(Ad)等数据。结果基于颈动脉WI[压力瞬时变化(d P/dt)与速度瞬时变化(d U/dt)的乘积,WI=(d P/dt)×(d U/dt)]技术的W1、W2、NA、β、Ep、AC、PWVβ等值与脉象诸参数有显著性相关,但二者反映的信息量及分析方法等存在一定的差异。结论应用WI概念可作为未来脉象领域一个新的研究方向。 展开更多
关键词 wave INTENSITY 超声检查 高血压 脉象
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基于Wave Intensity技术的高血压患者动脉弹性参数与血瘀证积分的相关性分析 被引量:8
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作者 魏世超 骆杰伟 +7 位作者 陈玮吉 林宁 郑星宇 李建卫 任林 孟晓嵘 张莹莹 黄昉萌 《世界中西医结合杂志》 2012年第5期407-409,共3页
目的探讨应用Wave Intensity(WI)技术检测高血压患者动脉弹性参数与血瘀证积分的相关性。方法用ALOKA Prosoundα10彩色多普勒超声仪检测119例高血压基础病患者,及62例健康对照者,获取颈总动脉β(僵硬度)、Ep(弹性模量)、AC(顺应性)、AI... 目的探讨应用Wave Intensity(WI)技术检测高血压患者动脉弹性参数与血瘀证积分的相关性。方法用ALOKA Prosoundα10彩色多普勒超声仪检测119例高血压基础病患者,及62例健康对照者,获取颈总动脉β(僵硬度)、Ep(弹性模量)、AC(顺应性)、AI(增大指数)、PWVβ(β值推导的脉搏波传导速度)、PWV-WI(WI值推导的脉搏波传导速度)等数据,并评估血瘀证积分。结果高血压组β、Ep、AI、PWVβ、PWV-WI均值均高于对照组均值,而AC均值低于对照组均值,两组比较差异有统计学意义(P<0.05),而高血压血瘀证积分与β、Ep、PWVβ、PWV-WI值与呈正相关(分别为r=0.750,P<0.001;r=0.776,P<0.001;r=0.870,P<0.001;r=0.418,P<0.001),与AC呈负相关(r=-0.769,P<0.001),差异有统计学意义,血瘀证积分与AI无明显相关(r=0.023,P=0.800)。结论基于Wave Intensity技术检测的动脉弹性参数能较准确反映血瘀证程度,具有临床应用价值。 展开更多
关键词 wave INTENSITY 超声检查 高血压 血瘀证 动脉弹性参数
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Rational arrangement of measuring shear wave speed in the liver 被引量:3
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作者 Takeshi Yokoo Tsutomu Kanefuji +10 位作者 Takeshi Suda Itsuo Nagayama Takahiro Hoshi Satoshi Abe Shinichi Morita Hiroteru Kamimura Kenya Kamimura Atsunori Tsuchiya Masaaki Takamura Kazuyoshi Yagi Shuji Terai 《World Journal of Gastroenterology》 SCIE CAS 2019年第20期2503-2513,共11页
BACKGROUND Shear wave speed has been widely applied to quantify a degree of liver fibrosis. However, there is no standardized procedure, which makes it difficult to utilize the speed universally. AIM To provide proced... BACKGROUND Shear wave speed has been widely applied to quantify a degree of liver fibrosis. However, there is no standardized procedure, which makes it difficult to utilize the speed universally. AIM To provide procedural standardization of shear wave speed measurement. METHODS Point shear wave elastography (pSWE) was measured in 781 patients, and twodimensional shear wave elastography (2dSWE) was measured on the same day in 18 cases. Regions-of-interest were placed at 12 sites, and the median and robust coefficient-of-variation (CVR) were calculated. A residual sum-of-square (Σdi2) was computed for bootstrap values of 1000 iterations in 18 cases with each assumption of 1 to 12 measurements. The proportion of the Σdi2 (%Σdi2) was calculated as the ratio of Σdi2 to pSWE after converting it based on the correlation between pSWE and 2dSWE. RESULTS The CVR showed a significantly broader distribution in the left lobe (P < 0.0001),and the smallest CVR in the right anterior segment that covered 95% cases was 40.4%. pSWE was significantly higher in the left lobe than in the right lobe (1.63 ± 0.78 m/s vs 1.61 ± 0.78 m/s, P = 0.0004), and the difference between the lobes became further discrete when the subjects were limited to the cases with a CVR less than 40.4% in any segment (1.76 ± 0.80 m/s vs 1.70 ± 0.82 m/s, P < 0.0001). The highest values of the CVR in every 0.1 m/s interval were plotted in convex upward along pSWE and peaked at 1.93 m/s. pSWE and 2dSWE were significantly correlated (P < 0.0001, r = 0.95). In 216000 resamples from 18 cases, the %Σdi2 of 12 sites was 8.0% and gradually increased as the acquisition sites decreased to reach a significant difference with a %Σdi2 of 7 sites (P = 0.027). CONCLUSION These data suggest that shear wave speed should be measured at 8 or more sites of spreading in both lobes. 展开更多
关键词 LIVER stiffness ultrasound SHEAR wave ELASTOGRAPHY Acoustic radiation force IMPULSE HETEROGENEITY
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Effects of ultrasonic waves on carbon dioxide solubility in brine at different pressures and temperatures 被引量:1
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作者 Hossein Hamidi Erfan Mohammadian +6 位作者 Amin Sharifi Haddad Roozbeh Rafati Amin Azdarpour Panteha Ghahri Adi Putra Pradana Bastian Andoni Chingis Akhmetov 《Petroleum Science》 SCIE CAS CSCD 2017年第3期597-604,共8页
The adverse impacts of CO2 emission on the global warming highlight the importance of carbon capture and storage technology and geological storage of CO2 under solubility trapping mechanisms. Enhancing the solubility ... The adverse impacts of CO2 emission on the global warming highlight the importance of carbon capture and storage technology and geological storage of CO2 under solubility trapping mechanisms. Enhancing the solubility of CO2 in formation water has always been the focus of research in the area of CO2 sequestration. Ultrasound techniques are one of the environmentally friendly methods that use high-intensity acoustic waves to improve gas solubility in liquids. Ultrasonic waves can alter the properties of different phases that lead to chemical reactions and provide a means to increase the solubility of CO2 in connate water. In this study, we investigated the effects of ultrasound on the solubility of CO2 in connate water under different conditions of pressure, temperature, and salinity. The results showed that the solubility of CO2 was improved with increasing pressure under ultrasonic effects.However, the solubility of CO2 was inversely proportional to the increase in brine salinity and temperature. Therefore,it was concluded that the solubility of CO2 might be enhanced in the presence of ultrasound. 展开更多
关键词 Carbon dioxide CO2 sequestration ultrasound High-frequency waves SOLUBILITY
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基于K-wave的经颅超声聚焦仿真研究
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作者 杨施成 刘逍逸 +3 位作者 王欢 刘春泽 陈友元 周红生 《声学技术》 CSCD 北大核心 2023年第1期39-45,共7页
由于颅骨形状不规则,声速、密度等声学参数分布不均匀,使用传统相控聚焦的方法进行经颅超声精确聚焦时会出现焦点偏移、焦点形状畸变、散焦的现象,时间反转法被认为是能够克服颅骨非均匀特性,实现经颅聚焦的有效手段。而利用传统有限元... 由于颅骨形状不规则,声速、密度等声学参数分布不均匀,使用传统相控聚焦的方法进行经颅超声精确聚焦时会出现焦点偏移、焦点形状畸变、散焦的现象,时间反转法被认为是能够克服颅骨非均匀特性,实现经颅聚焦的有效手段。而利用传统有限元,有限差分法进行数值仿真时,往往需要划分十分精密的网格进行计算,耗费大量的时间。K空间伪谱法通过在空间域上进行傅里叶变换,时间域上进行有限差分的方法求解声波方程,能够在降低计算网格密度的同时保证计算精度。为了克服颅骨对聚焦超声造成的焦移影响,同时避免声学模型计算量过大的问题,本文使用Matlab K-wave开源工具箱,对食蟹猴颅骨CT数据进行三维声学建模,实现了基于时间反转法的经颅超声聚焦,讨论了时间反转法对于颅骨不规则形状及非均匀声速造成的焦移的补偿。仿真结果表明,K-wave在提高计算速度的同时能够服务于精准经颅超声聚焦,且相较于传统基于声时差法的相控聚焦方法,时间反转法在预设焦点位置,焦点强度更高,焦斑形状更为规则,聚焦效果更好。 展开更多
关键词 经颅超声 时间反转 数值模拟 K-wave
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Non-invasive assessment of liver fibrosis using twodimensional shear wave elastography in patients with autoimmune liver diseases 被引量:8
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作者 Jie Zeng Ze-Ping Huang +2 位作者 Jian Zheng Tao Wu Rong-Qin Zheng 《World Journal of Gastroenterology》 SCIE CAS 2017年第26期4839-4846,共8页
AIM To determine the diagnostic accuracy of two-dimensional shear wave elastography(2D-SWE) for the noninvasive assessment of liver fibrosis in patients with autoimmune liver diseases(AILD) using liver biopsy as the r... AIM To determine the diagnostic accuracy of two-dimensional shear wave elastography(2D-SWE) for the noninvasive assessment of liver fibrosis in patients with autoimmune liver diseases(AILD) using liver biopsy as the reference standard.METHODS Patients with AILD who underwent liver biopsy and 2D-SWE were consecutively enrolled. Receiver operating characteristic(ROC) curves were constructed to assess the overall accuracy and to identify optimal cut-off values.RESULTS The characteristics of the diagnostic performance were determined for 114 patients with AILD. The areas under the ROC curves for significant fibrosis, severe fibrosis, and cirrhosis were 0.85, 0.85, and 0.86, respectively, and the optimal cut-off values associated with significant fibrosis(≥ F2), severe fibrosis(≥ F3), and cirrhosis(F4) were 9.7 k Pa, 13.2 k Pa and 16.3 k Pa, respectively. 2D-SWE showed sensitivity values of 81.7% for significant fibrosis, 83.0% for severe fibrosis,and 87.0% for cirrhosis, and the respective specificity values were 81.3%, 74.6%, and 80.2%. The overall concordance rate of the liver stiffness measurements obtained using 2D-SWE vs fibrosis stages was 53.5%.CONCLUSION2D-SWE showed promising diagnostic performance for assessing liver fibrosis stages and exhibited high cut-off values in patients with AILD. Low overall concordance rate was observed in the liver stiffness measurements obtained using 2D-SWE vs fibrosis stages. 展开更多
关键词 Autoimmune liver disease Liver fibrosis Two-dimensional shear wave elastography ultrasound Liver stiffness
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Shear wave velocity is a useful marker for managing nonalcoholic steatohepatitis 被引量:31
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作者 Akihiko Osaki Tomoyuki Kubota +11 位作者 Takeshi Suda Masato Igarashi Keisuke Nagasaki Atsunori Tsuchiya Masahiko Yano Yasushi Tamura Masaaki Takamura Hirokazu Kawai Satoshi Yamagiwa Toru Kikuchi Minoru Nomoto Yutaka Aoyagi 《World Journal of Gastroenterology》 SCIE CAS CSCD 2010年第23期2918-2925,共8页
AIM:To investigate whether a noninvasive measurement of tissue strain has a potential usefulness for management of nonalcoholic steatohepatitis(NASH).METHODS:In total 26 patients,23 NASHs and 3 normal controls were en... AIM:To investigate whether a noninvasive measurement of tissue strain has a potential usefulness for management of nonalcoholic steatohepatitis(NASH).METHODS:In total 26 patients,23 NASHs and 3 normal controls were enrolled in this study.NASH was staged based on Brunt criterion.At a region of interest(ROI),a shear wave was evoked by implementing an acoustic radiation force impulse(ARFI),and the propagation velocity was quantif ied.RESULTS:Shear wave velocity(SWV) could be reproducibly quantified at all ROIs in all subjects except for 4 NASH cases,in which a reliable SWV value was not calculated at several ROIs.An average SWV of 1.34 ± 0.26 m/s in fibrous stage 0-1 was significantly slower than 2.20 ± 0.74 m/s and 2.90 ± 1.01 m/s in stages 3 and 4,respectively,but was not significantly different from 1.79 ± 0.78 m/s in stage 2.When a cutoff value was set at 1.47 m/s,receiver operating characteristic analysis showed significance to dissociate stages 3 and 4 from stage 0-1(P=0.0092) with sensitivity,specificity and area under curve of 100%,75% and 94.2%,respectively.In addition,the correlation between SWV and hyaluronic acid was significant(P<0.0001),while a tendency toward negative correlation was observed with serum albumin(P=0.053).CONCLUSION:The clinical implementation of ARFI provides noninvasive repeated evaluations of liver stiffness at an arbitrary position,which has the potential to shed new light on NASH management. 展开更多
关键词 Nonalcoholic steatohepatitis ultrasound Liver stiffness measurement Shear wave velocity Acoustic radiation force impulse
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基于k-Wave的HIFU在组织中焦点偏移仿真研究 被引量:1
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作者 杨绍辉 徐皓胜 +2 位作者 曾伟 李伟东 曾德平 《压电与声光》 CAS 北大核心 2021年第3期340-345,共6页
该文利用k-Wave对高强度聚焦(HIFU)超声在多层组织中的焦点偏移现象进行了仿真及理论研究,分析了不同变量在非线性情况下对高强度聚焦超声穿过多层组织达到肝脏组织中形成的焦点位置的影响。研究发现,在换能器参数相同条件下,多层组织... 该文利用k-Wave对高强度聚焦(HIFU)超声在多层组织中的焦点偏移现象进行了仿真及理论研究,分析了不同变量在非线性情况下对高强度聚焦超声穿过多层组织达到肝脏组织中形成的焦点位置的影响。研究发现,在换能器参数相同条件下,多层组织的存在将导致焦点明显向换能器方向偏移,其聚焦位置相对于水域中焦点位置相差达到2.6 mm;肌肉厚度的增加将导致焦点向靠近换能器方向移动,脂肪厚度的增加将导致焦点向远离换能器方向移动。对于不同F数(F数表示换能器曲率半径与开口直径之比)的换能器,焦点位置的变化相对较小,这说明本研究的焦点偏移现象及结论对于不同的换能器有普适性,可为高强度聚焦超声精准高效治疗提供参考依据。 展开更多
关键词 高强度聚焦超声(HIFU) 焦点位置 k-wave 非线性 多层组织
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肌骨超声定位引导下冲击波治疗继发性手部肌腱粘连效果观察 被引量:1
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作者 张启富 周开斌 +2 位作者 龙耀斌 陈在娟 陈耀智 《广东医学》 CAS 2024年第3期318-323,共6页
目的研究肌骨超声定位引导下冲击波治疗手掌腕部和前臂外伤术后继发手部肌腱粘连的效果。方法手掌腕部和前臂外伤术后继发手部肌腱粘连患者80例,按随机数字表法分为治疗组和对照组,每组40例,两组患者均给予手掌腕部和前臂肌腱康复治疗,... 目的研究肌骨超声定位引导下冲击波治疗手掌腕部和前臂外伤术后继发手部肌腱粘连的效果。方法手掌腕部和前臂外伤术后继发手部肌腱粘连患者80例,按随机数字表法分为治疗组和对照组,每组40例,两组患者均给予手掌腕部和前臂肌腱康复治疗,如蜡疗、关节松动术、作业治疗。对照组患者,根据关节活动度受限情况,徒手检查确定手掌腕部和前臂肌腱粘连部位,给予冲击波治疗;治疗组患者,先对手掌腕部和前臂肌骨超声检查,确定肌腱粘连部位,进行标记定位,再根据定位进行冲击波治疗。两组患者均康复治疗4周,治疗前后对两组患者进行肌骨超声评估手部肌腱粘连程度,肌腱总主动活动度(TAM)测定,VAS疼痛视觉模拟评分评定,上肢及手功能DASH问卷评分测定。结果两组患者在治疗前手部肌腱粘连程度、肌腱TAM、疼痛VAS评分、上肢及手功能DASH评分比较差异无统计学意义(P>0.05),具有可比性。治疗4周后两组患者手部肌腱粘连程度明显改善,肌腱TAM增加,疼痛VAS评分降低,上肢及手功能DASH评分升高,但是治疗组患者手部肌腱粘连程度改善更明显,肌腱TAM增加更多,疼痛VAS评分降低更明显,上肢及手功能DASH评分升高更多,两组比较,差异有统计学意义(P<0.01)。结论肌骨超声定位引导下冲击波治疗结合常规康复治疗可以明显改善继发性手部肌腱粘连,恢复手部分功能。 展开更多
关键词 超声引导 冲击波 康复治疗 手肌腱粘连
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常规超声征象与剪切波弹性成像在甲状腺乳头状癌被膜侵犯预测颈部淋巴结转移风险中的价值 被引量:1
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作者 邵春晖 李培英 +2 位作者 罗永科 赵君智 马爱荣 《分子影像学杂志》 2024年第7期707-712,共6页
目的探讨常规超声征象与剪切波弹性成像弹性比(SWE-ER)在甲状腺乳头状癌(PTC)被膜侵犯预测颈部淋巴结转移(CLNM)风险中的价值。方法收集2022年6月~2024年3月在宝鸡市人民医院经术后病理证实的PTC患者87例共93个癌结节。根据术后病理分为... 目的探讨常规超声征象与剪切波弹性成像弹性比(SWE-ER)在甲状腺乳头状癌(PTC)被膜侵犯预测颈部淋巴结转移(CLNM)风险中的价值。方法收集2022年6月~2024年3月在宝鸡市人民医院经术后病理证实的PTC患者87例共93个癌结节。根据术后病理分为CLNM组和未发生CLNM组,回顾性分析甲状腺癌结节与被膜关系常规超声图像特征(癌结节与被膜接触情况、被膜连续性情况、被膜侵犯范围)及SWE-ER值,以病理诊断为金标准,绘制SWE-ER、结节与被膜关系不同界值下的ROC曲线,比较不同界值下预测颈部淋巴结转移风险的价值。利用二元Logistic回归方程计算发生CLNM患者的独立危险因素。结果发生CLNM组癌结节经线高于未发生CLNM组,差异有统计学意义(P<0.05)。发生CLNM组的被膜接触情况、被膜连续性及被膜侵犯范围占癌结节周长与未发生CLNM组相比,差异均有统计学意义(P<0.001)。发生CLNM组的SWE-ER低于未发生CLNM组,差异有统计学意义(P<0.05)。以病理为金标准,绘制不同截断值下评估CLNM风险的ROC曲线,其中以被膜侵犯范围占癌结节周长1/4为截断值的ROC曲线下面积为0.756(95%CI:0.652~0.859),诊断效能最高。二元Logistic回归多因素分析显示,甲状腺被膜中断、被膜侵犯范围占癌结节周长1/4~1/2、被膜侵犯范围占癌结节周长≥1/2均为发生CLNM的独立危险因素(P<0.05)。SWE-ER和癌结节被膜是否接触不能作为PTC发生CLNM的独立危险因素(P>0.05)。结论甲状腺癌结节与被膜的关系,尤其是对甲状腺癌结节被膜侵犯范围在超声预测CLNM中有较高诊断价值;被膜中断、被膜侵犯范围占癌结节周长1/4~1/2、被膜侵犯范围占癌结节周长≥1/2均为发生CLNM的独立危险因素,而SWE-ER和癌结节是否与被膜接触不能作为PTC发生CLNM的独立危险因素。 展开更多
关键词 甲状腺乳头状癌 被膜侵犯 颈部淋巴结转移 常规超声 剪切波弹性成像
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Estimation of temperature elevation generated by ultrasonic irradiation in biological tissues using the thermal wave method 被引量:1
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作者 刘晓宙 朱忆 +1 位作者 张飞 龚秀芬 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第2期302-307,共6页
In most previous models,simulation of the temperature generation in tissue is based on the Pennes bio-heat transfer equation,which implies an instantaneous thermal energy deposition in the medium.Due to the long therm... In most previous models,simulation of the temperature generation in tissue is based on the Pennes bio-heat transfer equation,which implies an instantaneous thermal energy deposition in the medium.Due to the long thermal relaxation time τ(20 s-30 s) in biological tissues,the actual temperature elevation during clinical treatments could be different from the value predicted by the Pennes bioheat equation.The thermal wave model of bio-heat transfer(TWMBT) defines a thermal relaxation time to describe the tissue heating from ultrasound exposure.In this paper,COMSOL Multiphysics 3.5a,a finite element method software package,is used to simulate the temperature response in tissues based on Pennes and TWMBT equations.We further discuss different factors in the bio-heat transfer model on the influence of the temperature rising and it is found that the temperature response in tissue under ultrasound exposure is a rising process with a declining rate.The thermal relaxation time inhibits the temperature elevation at the beginning of ultrasonic heating.Besides,thermal relaxation in TWMBT leads to lower temperature estimation than that based on Pennes equation during the same period of time.The blood flow carrying heat dominates most to the decline of temperature rising rate and the influence increases with temperature rising.On the contrary,heat diffusion,which can be described by thermal conductivity,has little effect on the temperature rising. 展开更多
关键词 thermal wave model of bioheat transfer temperature elevation ultrasound irradiation
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高频超声检查和剪切波弹性成像在尿毒症周围神经病变中的诊断价值研究
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作者 张兆光 徐慧颖 +4 位作者 李璇 刘静 孙昊琦 陈学勋 董晓红 《医学影像学杂志》 2024年第8期115-118,123,共5页
目的 探讨高频超声检查和剪切波弹性成像在尿毒症周围神经病变中的诊断价值。方法 选取我院收治的尿毒症患者96例,其中伴周围神经病变患者46例(UPN组),不伴周围神经病变患者50例(NUPN组),以及同期健康体检者40例(对照组)。三组均进行年... 目的 探讨高频超声检查和剪切波弹性成像在尿毒症周围神经病变中的诊断价值。方法 选取我院收治的尿毒症患者96例,其中伴周围神经病变患者46例(UPN组),不伴周围神经病变患者50例(NUPN组),以及同期健康体检者40例(对照组)。三组均进行年龄、性别、病史时长、实验室检查、电生理等指标检测,同时行双侧胫神经高频超声检查探查及剪切波弹性成像测量胫神经横截面积(CSA)、杨氏模量(Emean)、长径、宽径、周长,绘制受试者工作特征曲线(ROC),评价各项指标的诊断效能。结果 与对照组比较,UPN组与NUPN组血肌酐、血尿素氮、血磷浓度显著升高,而白蛋白显著降低,差异有统计学意义(P<0.05);与NUPN组比较,UPN组病史时长、β_2-微球蛋白、甲状旁腺素(PTH)、血钾浓度、血磷浓度均显著升高,而血红蛋白、白蛋白、血钠浓度均显著下降,差异有统计学意义(P<0.05)。三组胫神经测量值组间比较,UPN组测得胫神经的Emean、CSA、周长等均高于NUPN组及对照组,差异有统计学意义(P<0.05);测得三组样本胫神经的Emean、CSA、周长的曲线下面积(AUC)分别为0.899、0.675、0.582,最佳截断值分别为55.56 kPa、0.23 cm~2、1.91 cm。结论 高频超声检查和剪切波弹性成像在尿毒症周围神经病变中具有较好的诊断价值,可作为临床尿毒症周围神经病变的诊断和监测手段。 展开更多
关键词 尿毒症周围神经病变 胫神经 杨氏模量 高频超声检查 剪切波弹性成像
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经腹部超声、经阴道超声、剪切波弹性成像联合检查对宫颈癌的诊断价值 被引量:1
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作者 罗莹莹 冉青 李会霞 《癌症进展》 2024年第2期206-208,213,共4页
目的探讨经腹部超声、经阴道超声、剪切波弹性成像联合检查对宫颈癌的诊断价值。方法选取98例宫颈病变患者,所有患者均行经腹部超声、经阴道超声、剪切波弹性成像及病理检查。病理检查结果显示,宫颈癌患者58例,宫颈上皮内瘤变(CIN)患者2... 目的探讨经腹部超声、经阴道超声、剪切波弹性成像联合检查对宫颈癌的诊断价值。方法选取98例宫颈病变患者,所有患者均行经腹部超声、经阴道超声、剪切波弹性成像及病理检查。病理检查结果显示,宫颈癌患者58例,宫颈上皮内瘤变(CIN)患者24例,其他宫颈良性病变患者16例。比较宫颈癌、CIN及其他宫颈良性病变患者弹性模量值的最大值及平均值。以病理检查结果为金标准,分析经腹部超声、经阴道超声、剪切波弹性成像单独及联合检查对宫颈癌的诊断价值。结果宫颈癌患者弹性模量值的最大值及平均值均高于CIN及其他宫颈良性病变患者,差异均有统计学意义(P﹤0.05)。经腹部超声、经阴道超声、剪切波弹性成像联合检查诊断宫颈癌的灵敏度、特异度、准确度、阳性预测值、阴性预测值分别为94.83%、95.00%、94.90%、96.49%、92.68%,均高于三者单独检查。结论经腹部超声、经阴道超声、剪切波弹性成像联合检查对宫颈癌具有较高的诊断效能。 展开更多
关键词 宫颈癌 剪切波弹性成像 经阴道超声 经腹部超声
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常规肠道超声结合剪切波弹性成像在克罗恩病活动性预测中的作用
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作者 冉青 汤莹莹 +1 位作者 喻红霞 甄艳华 《河南医学研究》 CAS 2024年第20期3789-3794,共6页
目的 利用剪切波弹性成像(SWE)定量评估肠壁硬度,探讨常规肠道超声(IUS)联合SWE在克罗恩病(CD)活动性评估中的应用价值。方法 纳入62例CD患者,记录年龄、性别、体重指数,均使用常规IUS及SWE测量最严重病变肠段的肠壁厚度(BWT)及杨氏模... 目的 利用剪切波弹性成像(SWE)定量评估肠壁硬度,探讨常规肠道超声(IUS)联合SWE在克罗恩病(CD)活动性评估中的应用价值。方法 纳入62例CD患者,记录年龄、性别、体重指数,均使用常规IUS及SWE测量最严重病变肠段的肠壁厚度(BWT)及杨氏模量弹性模量平均值(Emean),根据简化克罗恩病内镜下评分(SES-CD)将CD患者分为活动期和缓解期。比较CD活动期和缓解期的BWT和弹性模量值差异,计算常规IUS联合SWE诊断CD活动性的最佳截断值和诊断效能。结果 CD组活动期BWT及Emean高于缓解期,活动期的Limberg分级高于缓解期(P<0.05)。以Emean>12.65 kPa为截断值时,超声诊断CD活动性的敏感性和特异性分别为66.7%和85.7%;而联合使用IUS和SWE时,诊断CD活动性的敏感性和特异性分别为93.8%和87.5%。结论 常规IUS联合SWE可定量评估CD患者的肠壁硬度及厚度,对辅助评估CD活动性具有积极意义。 展开更多
关键词 常规肠道超声 剪切波弹性成像 克罗恩病
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