IEEE Ultrasonics Symposium, 2005.最新文献

{"title":"Evaluation of array signal processing methods for ultrasound-based arterial pulse wave velocity measurements on in vitro and in vivo data","authors":"A. Dentinger, R. Hoctor, K. Thomenius","doi":"10.1109/ULTSYM.2005.1602789","DOIUrl":"https://doi.org/10.1109/ULTSYM.2005.1602789","url":null,"abstract":"In this paper we evaluate an improved version of a signal processing approach recently proposed by the authors for estimating arterial pulse wave velocity (PWV) in a uniform arterial segment based on ultrasound measurements. The modifications are described, along with the experimental set-up for their evaluation. In general, results of physical experiments and simulations indicate that the new modifications provide a robust approach to PWV estimation. Non-invasive, in vivo assessment of the local elastic properties of an artery is a desirable capability, both in experimental physiology and in medicine. The arterial pulse wave velocity (PWV) in a short uniform segment of an artery is indicative of the local elastic state of the segment, but pulse wave reflections are always present throughout the arterial system and are a well-recognized source of error in PWV measurement (1). Elimination of estimation bias due to reflections is required if the PWV is to be used to compute parameters such as the compliance of the artery. Ultrasound is a suitable modality for the local PWV estimation problem, as it is for many problems of noninvasive, in vivo biomechanical assessment. Recently the authors (2) showed that pulse wave velocity estimation from several ultrasound measurements taken along a uniform arterial segment is mathematically equivalent to the broadband directional of arrival problem found in radar and sonar. The presence of a reflection wave traveling at the PWV, but in the opposite direction from the forward wave makes the PWV problem similar to the symmetric multipath case in the direction-of-arrival problem (3). Consequently, there is a great deal of work in signal processing literature dealing with the direction-of-arrival estimation problem in this form that can be applied the arterial PWV estimation using ultrasound by way of the problem formulation given in (2). In (4), a method for the PWV problem based on a least squares approach was presented and results of application to in vivo were presented for data taken using a 10 MHz linear probe positioned to acquire 8 beams spaced by 5.6 mm along the flow axis of the left common carotid artery (CCA). The technique of (4) produced estimates in a realistic range, but with large estimation variance on the order of 30-40%. This paper seeks to provide a more detailed evaluation of the general method, using new signal processing approaches for reduction of estimation bias. This evaluation is done by simulation, test tank experiments and further data from the CCAs of healthy volunteers.","PeriodicalId":302030,"journal":{"name":"IEEE Ultrasonics Symposium, 2005.","volume":"71 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129112992","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysis of crosstalk between fluid coupled cmut membranes","authors":"P. Eccardt, A. Lohfink, H. Garssen","doi":"10.1109/ULTSYM.2005.1602922","DOIUrl":"https://doi.org/10.1109/ULTSYM.2005.1602922","url":null,"abstract":"Crosstalk between array elements is an important and intensively discussed topic for CMUTs. For operation in fluids crosstalk effects significantly influence the dynamic range at pulse-echo mode, directivity pattern and frequency response and are highly undesired for medical application. On the other hand, crosstalk effects between the membranes and the surrounding fluid are used for other CMUT applications like pumping and mixing in micro fluidic channels. So far, coupling between the membranes and the surrounding fluid was mostly described as Stonely or Scholte waves at the CMUT surface. This paper presents an analytical description of this crosstalk effect between CMUT membranes. The basic idea is that the elastic membranes act as a complex load onto the fluid. Waves at such an interface are comparable to gravitational waves at a free water surface. Considering a homogeneously stiff and mass loaded interface, the speed of sound of an evanescent fluid wave at this interface will be described analytically with a simple formula for a fluid half space bounded by a complex acoustical impedance. The approach was validated with FEM simulations. Investigations with respect to the influence of discretisation and size of typical membranes are discussed as well as the influence of membrane stiffness, membrane mass and inactive area between membranes onto the speed of sound and the intensity distribution of this surface wave. The wave is highly dispersive, its speed of sound increases with increasing stiffness and with decreasing frequency. Both effects are monotonic but nonlinear for frequencies above the membrane resonance. Near membrane resonance the speed of sound approaches zero. FEM simulations of typical CMUT membranes show that these surface waves have a significant influence onto the array behavior and can be well described by the presented analytical approach.","PeriodicalId":302030,"journal":{"name":"IEEE Ultrasonics Symposium, 2005.","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129204858","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dilution system identification methods for contrast ultrasound ejection fraction assessment","authors":"M. Mischi, A. Jansen, H. Korsten","doi":"10.1109/ULTSYM.2005.1602986","DOIUrl":"https://doi.org/10.1109/ULTSYM.2005.1602986","url":null,"abstract":"Standard left ventricle (LV) ejection fraction (EF) measurements by image analysis techniques are typically time- consuming. Indicator dilution methods allow a fast EF mea- surement, but their application is limited due to the need for cardiac catheterization. The injection of an ultrasound contrast agent bolus permits a non-invasive indicator dilution curve (IDC) detection, however, a ventricular contrast injection remains necessary. We have recently proposed the use of LV dilution system identification methods for a minimally-invasive EF measurement, in which the contrast bolus is injected in an arm vein. In this paper, we present, validate, and compare two least-mean-squares (LMS) algorithms for the LV impulse response estimation and the LV EF assessment. The left atrium and LV IDC represent the input and output of the LV dilution system. In the first algorithm, the LV dilution impulse response is determined by the solution of the Wiener-Hopf equation and fitted by a mono-compartment model for the EF assessment. In the second algorithm, the LV impulse response is parameterized by the model before the application of the LMS algorithm. The algorithms are validated by 50 measurements in patients with EF between 10% and 80%. The measurements are compared with echocardiographic bi-plane estimates after contrast opacification. The correlation coefficients are 0.68 and 0.88 and the standard deviations are 11.8% and 8.1% for the first and second algorithm, respectively. We may conclude that EF measurements by contrast echocardiography are feasible. Adding a priori knowledge in the system identification algo- rithm leads to an increased accuracy of the measurement.","PeriodicalId":302030,"journal":{"name":"IEEE Ultrasonics Symposium, 2005.","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123854023","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Detection of the myocardial boundary in the left ventricle from simultaneously acquired triplane ultrasound images using multi view active appearance motion models","authors":"J. Hansegård, S. Urheim, E. Steen, H. Torp, B. Olstad, S. Malm, S. Rabben","doi":"10.1109/ULTSYM.2005.1603336","DOIUrl":"https://doi.org/10.1109/ULTSYM.2005.1603336","url":null,"abstract":"We report a new algorithm for detecting the LV myocardial boundary from simultaneously acquired triplane US image sequences using Multi View Active Appearance Motion Models. Coupled boundary detection in three planes can po- tentially increase the accuracy of LV volume measurements, and also increase the robustness of the boundary detection over traditional methods. A database of triplane image sequences from full cardiac cycles, including the standard A4CH, A2CH, and ALAX views were established from 20 volunteers, including 12 healthy persons and 8 persons suffering from heart disease. For each dataset the LV myocardial boundary was manually outlined, and the ED and ES frames were determined visually for phase normalization of the cycles. The evaluation of the MVAAMM was performed using a leave one out approach. The mean point distance between manually and automatically determined contours were 4.1±1.9 mm, the volume error was 7.0±14 ml, and fractional volume error was 8.5±16 %. Volume detection using the automatic method showed excellent correlation to the manual method (R 2 =0.87). Common ultrasound artefacts such as dropouts were handled well by the MVAAMM since the detection in the three image planes were coupled. The views with the largest point distance had one or more foreshortened views. A larger training database may improve the performance in such cases.","PeriodicalId":302030,"journal":{"name":"IEEE Ultrasonics Symposium, 2005.","volume":"61 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123628825","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ultrasonic measurement of the human achilles tendon stress during loading: preliminary experimental and theoretical results","authors":"C. Roux, M. Defontaine","doi":"10.1109/ULTSYM.2005.1603186","DOIUrl":"https://doi.org/10.1109/ULTSYM.2005.1603186","url":null,"abstract":"Our purpose is to present a non-invasive quantitative ultrasound (US) method to measure the level of stress in the human Achilles tendon during effort. This technique, first developed for the equine forelimb tendon by the UMR INRAENVA BPLC (Maisons-Alfort, France) and the LUSSI, consists in the measurement of the US velocity using an axialtransmission method along the tendon fibers axis, during effort. The tendon celerity is estimated by the analysis of a particular longitudinal wave called Lateral Wave (LW). A dedicated electronic and probe modules have been developed in order to acquire simultaneously the ultrasonic and the force data in the Achilles tendon during a specific effort. Several types of muscular exercises have been tested, and particularly cycles of isometric contraction of the triceps surae muscle/Achilles tendon complex. As expected, the tendon velocity is highly correlated with the effort. At the same time, we have been developing a 2D simulation of the tendon waves propagation to better understand the propagation and to correctly estimate the US tendon velocity in the complex RF signals. This model uses partial differential wave propagation equations solved by pseudospectral and finite difference methods, including Perfectly Matched Layers (PML). Keywords-lateral wave; tendon stress; tendon celerity; wave propagation model","PeriodicalId":302030,"journal":{"name":"IEEE Ultrasonics Symposium, 2005.","volume":"78 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121379407","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design of SAW bandpass filters using weighted least squares (WLS) technique","authors":"A. S. Rukhlenko","doi":"10.1109/ULTSYM.2005.1603316","DOIUrl":"https://doi.org/10.1109/ULTSYM.2005.1603316","url":null,"abstract":"It has been demonstrated by several authors that the well-known weighted least squares (WLS) approximation can be equiripple if a suitable weighting function is applied. In the pre- sent paper, the WLS algorithm is generalized to SAW filter syn- thesis with prescribed magnitude and phase specifications. Several weighting techniques producing quasi-equiripple designs are pre- sented. The frequency sampling technique is used for SAW filter frequency response approximation to reduce the number of the optimized variables. The WLS algorithm rapidly converges both for linear and non-linear phase SAW filters. Typically, no more than 5-10 iterations are required to obtain the WLS solution to accuracy better than 0.5-1 dB in the stopband when compared with the optimum Chebyshev approximation. Moreover, it is shown that the WLS technique can be effectively applied for sec- ond-order effect compensation.","PeriodicalId":302030,"journal":{"name":"IEEE Ultrasonics Symposium, 2005.","volume":"57 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121556426","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A simple method to reduce aliasing artifacts in color flow mode imaging","authors":"J. Udesen, S. Nikolov, J. A. Jensen","doi":"10.1109/ULTSYM.2005.1603104","DOIUrl":"https://doi.org/10.1109/ULTSYM.2005.1603104","url":null,"abstract":"It is a well known limitation in conventional blood velocity estimation using a phase estimation approach, that aliasing artifacts are present, when the blood velocities exceed a value determined by half the pulse repetition frequency (the Nyquist frequency). This paper proposes a simple anti-aliasing discriminator (AAD) method based on using two different pulse repetition frequencies to increase the aliasing limit to twice the Nyquist frequency. The method is evaluated in simulations using the Field II program. The axial velocity in a virtual blood vessel is found along one axial line, where N=10 emissions are used for each velocity estimate. Mean standard deviation and mean absolute bias are 4.9% and 23.8%, respectively, when no attempt is done to suppress the aliasing. When the AAD is used the corresponding values are 3.4% and 1.0% .W hen median filtering is applied, the values are 1.1% and 0.6% .T he method is evaluated experimentally using the ultrasound scanner RASMUS and a circulating flowrig with parabolic flow. The mean standard deviation and mean absolute bias are 4.0% and 20.3%, respectively, when no attempt is done to suppress the aliasing. When the anti-aliasing discriminator is used the corresponding values are 3.6% and 1.2%. The values are 1.0% and 0.8% ,w hen median filtering is performed.","PeriodicalId":302030,"journal":{"name":"IEEE Ultrasonics Symposium, 2005.","volume":"181 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124539871","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pulling of SAW resonators for wireless sensor application","authors":"E. Guliyev, S. Klett","doi":"10.1109/ULTSYM.2005.1603320","DOIUrl":"https://doi.org/10.1109/ULTSYM.2005.1603320","url":null,"abstract":"SAW resonators are particularly suitable for passive wireless sensing because of the high Q factor (storage of rf energy) and the possibility to change their resonance be- haviour influenced by an external measurand (frequency pulling). The sensor is build not only by a physical af- fecting of the acoustic wave but also by an electrical interaction outside the resonator (e.g. capacitive or inductive). The sensor signal is determined by the ex- ternal circuit elements and manifests in a fre- quency and amplitude shift. The pulling frequency and the optimum pulling span, also the transmitted power are estimated by the external reactive circuit ele- ments, as well as by the SAW-Resonator characteristic. To obtain the maximum power transmis- sion, a matching between the sensor element and the antenna for wireless interrogation is necessary; simultaneously, one element of the matching network is the sensing element that pulls the frequency. For well-designed sensors, the parameters of equivalent circuitry of the resonator have to be estimated with a high accuracy, in order to simulate the resonator pulling in combination with different matching networks. Thus, from all the L-, Pi- and T-sections, the eligible con- figuration were selected and tested in order to ensure the maximum power transmission in a wide pulling range. This paper presents simulation and ex- perimental results for designing proper sensor systems.","PeriodicalId":302030,"journal":{"name":"IEEE Ultrasonics Symposium, 2005.","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127625042","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fast reconstruction of quantitative tissue elasticity image based on modified 3-d finite-element model","authors":"M. Yamakawa, T. Shiina, T. Matsumura, T. Mitake","doi":"10.1109/ULTSYM.2005.1603208","DOIUrl":"https://doi.org/10.1109/ULTSYM.2005.1603208","url":null,"abstract":"For tissue elasticity imaging, strain imaging technique is being used in clinical tests (3). However, strain image corresponds to visualizing the qualitative information about tissue hardness. Therefore, in this study, we propose a method for reconstructing tissue hardness as quantitatively as possible from ultrasound data using 1-D array ultrasonic probe. In this method, we use a modified 3-D finite-element model. Using this model, it becomes possible to estimate Young's modulus only from the 2-D strain distribution. Moreover, since we can use the more realistic 3-D elastic equations in the modified 3-D model, it is possible to estimate Young's modulus more quantitatively. We compared the performance of the proposed method with other methods based on the 1-D model, 2-D model and 3-D model. Consequently, although the proposed method is comparable to the 3-D model method in accuracy, this method has 4.0 times precision better than the 1-D model method, 3.0 to 1.5 times precision better than the 2-D model method. Moreover, the proposed method can attain high-speed processing about 170 times faster than the method using 3-D model.","PeriodicalId":302030,"journal":{"name":"IEEE Ultrasonics Symposium, 2005.","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128074729","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development of monolithic CMOS-SAW oscillator","authors":"M. Furuhata, A. Yajima, K. Goto, H. Sato, T. Funasaka, S. Kawano, S. Fujii, T. Higuchi, M. Ueno, T. Karaki, M. Adachi","doi":"10.1109/ULTSYM.2005.1603318","DOIUrl":"https://doi.org/10.1109/ULTSYM.2005.1603318","url":null,"abstract":"In recent years, miniaturization and high accuracy of mobile communication systems have become essential. Because of good phase noise performance, the SAW clock has become a viable option for data transmission. However, a SAW oscillator is usually made up of a SAW device and a CMOS-IC separately, and this large size limits its use in mobile communication systems. This paper covers the development of the smallest monolithic SAW oscillator using thin film ZnO deposited on a CMOS-IC. The SAW device and the IC have been combined into a single unit, and the total thickness is nearly the same as the IC.","PeriodicalId":302030,"journal":{"name":"IEEE Ultrasonics Symposium, 2005.","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128134315","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}