Pub Date : 1999-10-17DOI: 10.1109/ULTSYM.1999.849484
Seung-Hee Lee, Y. Roh, Woo-Seok Han, Yeon-Bo Kim
This paper describes development of a new ultrasonic traveling wave motor of a quite simple structure that can move bi-directionally in both self moving and non-self moving modes. With the finite element method, we design and verify validity of the new structure, and determine its optimal structure and boundary conditions for proper generation of the traveling wave. Based on the results, a prototype of the motor is fabricated and characterized, which thereby proves practical applicability of the new structure.
{"title":"Design and fabrication of ultrasonic traveling wave bi-directional linear motors","authors":"Seung-Hee Lee, Y. Roh, Woo-Seok Han, Yeon-Bo Kim","doi":"10.1109/ULTSYM.1999.849484","DOIUrl":"https://doi.org/10.1109/ULTSYM.1999.849484","url":null,"abstract":"This paper describes development of a new ultrasonic traveling wave motor of a quite simple structure that can move bi-directionally in both self moving and non-self moving modes. With the finite element method, we design and verify validity of the new structure, and determine its optimal structure and boundary conditions for proper generation of the traveling wave. Based on the results, a prototype of the motor is fabricated and characterized, which thereby proves practical applicability of the new structure.","PeriodicalId":339424,"journal":{"name":"1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027)","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133497320","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}
Pub Date : 1999-10-17DOI: 10.1109/ULTSYM.1999.849487
Chunsheng Zhao, Guiqin Wang, Long Jin
This paper developed a new type of self-correction ultrasonic motor using standing wave. It differs from current self-correction ultrasonic motors in driving and control method. In operating stage of self-correction, the slits on rotor of the motor stay always at the projection teeth on the stator when two signals applied simultaneously to piezoelectric element which is adhered to stator are in phase for the new type of self-correction motor, but in opposite phase for current types of self-correction motor. It is notable that the projection teeth are located on the crests and troughs of a vibration mode of the stator for the new self-correction motor, but on the nodal diameters of a vibration mode of stator for current types. The experiments have shown that the self-correction function of the new type of self-correction motor is stronger than that of current types of self-correction motor. The rotation mechanism of the new type of self-correction motor is described in the paper.
{"title":"A new type of self-correction ultrasonic motor using standing wave","authors":"Chunsheng Zhao, Guiqin Wang, Long Jin","doi":"10.1109/ULTSYM.1999.849487","DOIUrl":"https://doi.org/10.1109/ULTSYM.1999.849487","url":null,"abstract":"This paper developed a new type of self-correction ultrasonic motor using standing wave. It differs from current self-correction ultrasonic motors in driving and control method. In operating stage of self-correction, the slits on rotor of the motor stay always at the projection teeth on the stator when two signals applied simultaneously to piezoelectric element which is adhered to stator are in phase for the new type of self-correction motor, but in opposite phase for current types of self-correction motor. It is notable that the projection teeth are located on the crests and troughs of a vibration mode of the stator for the new self-correction motor, but on the nodal diameters of a vibration mode of stator for current types. The experiments have shown that the self-correction function of the new type of self-correction motor is stronger than that of current types of self-correction motor. The rotation mechanism of the new type of self-correction motor is described in the paper.","PeriodicalId":339424,"journal":{"name":"1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027)","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133516816","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}
Pub Date : 1999-10-17DOI: 10.1109/ULTSYM.1999.849352
S. Doberstein, V. Malyukhov, V. Razgonyaev
This paper presents wideband three-transducer SAW filters using unidirectional IDTs on U-shaped MSCs. In the filters a self-matching effect is used when a static capacitance of an IDT is compensated by an acoustic radiation susceptance. 30-70 MHz filters on 128° YX, 64° YX, 41° YX LiNbO3 have shown an insertion loss of 1 dB, 3-dB fractional bandwidth of 3.5-10% with low ripple of 0.1 dB, stopband attenuation of 10-15 dB. 165, 169 MHz SAW filters for the front-end stages of mobile transceivers have shown an insertion loss of 1-1.8 dB, 3-dB bandwidth of 5.7-11 MHz with a ripple of 0.2 dB, stopband attenuation of 12-40 dB. The filters did not require matching networks, were mounted in the SMD packages (5×5×1.8 mm).
{"title":"Wideband three-transducer SAW filters using unidirectional IDTs on U-shaped MSCs with insertion loss of 1 dB","authors":"S. Doberstein, V. Malyukhov, V. Razgonyaev","doi":"10.1109/ULTSYM.1999.849352","DOIUrl":"https://doi.org/10.1109/ULTSYM.1999.849352","url":null,"abstract":"This paper presents wideband three-transducer SAW filters using unidirectional IDTs on U-shaped MSCs. In the filters a self-matching effect is used when a static capacitance of an IDT is compensated by an acoustic radiation susceptance. 30-70 MHz filters on 128° YX, 64° YX, 41° YX LiNbO3 have shown an insertion loss of 1 dB, 3-dB fractional bandwidth of 3.5-10% with low ripple of 0.1 dB, stopband attenuation of 10-15 dB. 165, 169 MHz SAW filters for the front-end stages of mobile transceivers have shown an insertion loss of 1-1.8 dB, 3-dB bandwidth of 5.7-11 MHz with a ripple of 0.2 dB, stopband attenuation of 12-40 dB. The filters did not require matching networks, were mounted in the SMD packages (5×5×1.8 mm).","PeriodicalId":339424,"journal":{"name":"1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027)","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132293592","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}
Pub Date : 1999-10-17DOI: 10.1109/ULTSYM.1999.849519
R. Addison, A. Mckie
Laser-based ultrasound offers the capability for performing ultrasonic inspections in remote and limited access areas by coupling the lasers through optical fibers. The key factors needed for successfully implementing a fiber-based remote and limited access LBU system will be described. We report on design tradeoffs and preliminary experiments that have been conducted with a fiber-based inspection system.
{"title":"System considerations for remote and limited access laser-based ultrasound","authors":"R. Addison, A. Mckie","doi":"10.1109/ULTSYM.1999.849519","DOIUrl":"https://doi.org/10.1109/ULTSYM.1999.849519","url":null,"abstract":"Laser-based ultrasound offers the capability for performing ultrasonic inspections in remote and limited access areas by coupling the lasers through optical fibers. The key factors needed for successfully implementing a fiber-based remote and limited access LBU system will be described. We report on design tradeoffs and preliminary experiments that have been conducted with a fiber-based inspection system.","PeriodicalId":339424,"journal":{"name":"1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027)","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114359462","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}
Pub Date : 1999-10-17DOI: 10.1109/ULTSYM.1999.849362
A. Baghai-Wadji
In this paper we consider the massloading problem in surface acoustic wave devices under fairly general conditions. We assume a finite number of non-equidistantly spaced electrodes with arbitrary cross-section geometries and material constitutions. Electrical loading effect is also addressed and a model is presented which is a generalization of this author's model published in 1989. To solve our problem we have considerably improved the capabilities of the Fast-MoM analysis technique. It turns out that it is possible to generate bivariate universal functions which are frequency, material, and geometry independent. The purpose of this paper is to provide an idea about how the universal functions are created. Having the universal functions we simply have to follow the following recipe to solve a practical problem: (1) discretize the boundaries of electrodes; (2) find the positions of a number of sampling points; (3) sample the universal functions; (4) construct a square matrix; (5) solve a system of equations. If the frequency, or the material, or the geometry of an electrode alters only the locations of the sampling points change. In this paper we present examples for the universal functions and discuss one application of the Fast-MoM.
{"title":"Material, geometry, and frequency independent bivariate universal functions for the analysis of mechanical and electrical loading effects in acoustic devices: A Fast-MoM approach","authors":"A. Baghai-Wadji","doi":"10.1109/ULTSYM.1999.849362","DOIUrl":"https://doi.org/10.1109/ULTSYM.1999.849362","url":null,"abstract":"In this paper we consider the massloading problem in surface acoustic wave devices under fairly general conditions. We assume a finite number of non-equidistantly spaced electrodes with arbitrary cross-section geometries and material constitutions. Electrical loading effect is also addressed and a model is presented which is a generalization of this author's model published in 1989. To solve our problem we have considerably improved the capabilities of the Fast-MoM analysis technique. It turns out that it is possible to generate bivariate universal functions which are frequency, material, and geometry independent. The purpose of this paper is to provide an idea about how the universal functions are created. Having the universal functions we simply have to follow the following recipe to solve a practical problem: (1) discretize the boundaries of electrodes; (2) find the positions of a number of sampling points; (3) sample the universal functions; (4) construct a square matrix; (5) solve a system of equations. If the frequency, or the material, or the geometry of an electrode alters only the locations of the sampling points change. In this paper we present examples for the universal functions and discuss one application of the Fast-MoM.","PeriodicalId":339424,"journal":{"name":"1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027)","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124890507","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}
Pub Date : 1999-10-17DOI: 10.1109/ULTSYM.1999.849323
A. Bouakaz, K. Shung
Recent studies have shown that ultrasound contrast agent may be used to deliver drugs. These drugs are directly released to the target tissue when the microspheres are exposed to high amplitude acoustic waves. The goal of this study was to investigate the destruction of microspheres by ultrasound waves to better understand the rates of transport and release that could provide the optimal spatial and temporal pattern for a drug delivery system. Experimental investigations have demonstrated that depending on the transmitted frequency, certain microsphere sizes within the same distribution are easier to rupture than others, and therefore can be selectively destroyed. These results were confirmed by measurements performed on filtered distributions. The study illustrates the potentials of ultrasound contrast agent for pharmacological applications. Different therapeutic compounds can be loaded within microspheres of different sizes and the release can be selectively activated from different regions in the size distribution.
{"title":"Selective destruction of contrast agent microspheres [drug delivery application]","authors":"A. Bouakaz, K. Shung","doi":"10.1109/ULTSYM.1999.849323","DOIUrl":"https://doi.org/10.1109/ULTSYM.1999.849323","url":null,"abstract":"Recent studies have shown that ultrasound contrast agent may be used to deliver drugs. These drugs are directly released to the target tissue when the microspheres are exposed to high amplitude acoustic waves. The goal of this study was to investigate the destruction of microspheres by ultrasound waves to better understand the rates of transport and release that could provide the optimal spatial and temporal pattern for a drug delivery system. Experimental investigations have demonstrated that depending on the transmitted frequency, certain microsphere sizes within the same distribution are easier to rupture than others, and therefore can be selectively destroyed. These results were confirmed by measurements performed on filtered distributions. The study illustrates the potentials of ultrasound contrast agent for pharmacological applications. Different therapeutic compounds can be loaded within microspheres of different sizes and the release can be selectively activated from different regions in the size distribution.","PeriodicalId":339424,"journal":{"name":"1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027)","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124978363","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}
Pub Date : 1999-10-17DOI: 10.1109/ULTSYM.1999.849261
E. Feleppa, T. Liu, A. Kalisz, D. Manolakis, W. Gnadt, F. Lizzi, W. Fair, K. Balaji, C. Porter, H. Tsai, V. Reuter
Spectrum analysis of ultrasonic echo signals has been showing potential for distinguishing cancerous from non-cancerous prostate tissues. Recently, using neural networks to classify tissue from spectrum analysis results has provided a powerful basis for imaging, guiding biopsies, and planning, executing, and monitoring therapy. ROC curves derived from leave-one-out evaluations of neural-network classifier performance have an area of 0.87/spl plusmn/0.04 compared to an area of 0.64/spl plusmn/0.04 for B-mode methods, which implies significantly superior differentiation of cancerous from non-cancerous prostate tissue.
{"title":"2-D images for biopsy guidance and 3-D images for treatment planning and monitoring of prostate cancer based upon spectrum analysis and neural-network classification","authors":"E. Feleppa, T. Liu, A. Kalisz, D. Manolakis, W. Gnadt, F. Lizzi, W. Fair, K. Balaji, C. Porter, H. Tsai, V. Reuter","doi":"10.1109/ULTSYM.1999.849261","DOIUrl":"https://doi.org/10.1109/ULTSYM.1999.849261","url":null,"abstract":"Spectrum analysis of ultrasonic echo signals has been showing potential for distinguishing cancerous from non-cancerous prostate tissues. Recently, using neural networks to classify tissue from spectrum analysis results has provided a powerful basis for imaging, guiding biopsies, and planning, executing, and monitoring therapy. ROC curves derived from leave-one-out evaluations of neural-network classifier performance have an area of 0.87/spl plusmn/0.04 compared to an area of 0.64/spl plusmn/0.04 for B-mode methods, which implies significantly superior differentiation of cancerous from non-cancerous prostate tissue.","PeriodicalId":339424,"journal":{"name":"1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027)","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131950903","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}
Pub Date : 1999-10-17DOI: 10.1109/ULTSYM.1999.849267
S. Umemura, K. Sasaki, K. Kawabata, T. Azuma, N. Sanghvi
The split-focus approach has a potential to substantially improve the throughput of coagulation HIFU treatment. A prototype split-focus transducer with two elements at 4.3 MHz combined with a small imaging probe at 6.5 MHz was constructed for transrectal treatment of a prostate. Computer simulation predicted that a coagulation volume approximately three times larger than single-spot focus would be obtained with split focus. Swine liver lobes were intraoperatively insonated for 4 s at a peak intensity of 850 W/cm/sup 2/. A lesion of coagulative necrosis three to six times larger than single-spot focus in volume was formed with the split focus. A canine prostate was then transrectally treated. A cavity, 0.35-0.45 cm/sup 3/ in volume, was formed with only four shots of split-focus insonation.
{"title":"Coagulation of swine liver and canine prostrate with a prototype split-focus transducer","authors":"S. Umemura, K. Sasaki, K. Kawabata, T. Azuma, N. Sanghvi","doi":"10.1109/ULTSYM.1999.849267","DOIUrl":"https://doi.org/10.1109/ULTSYM.1999.849267","url":null,"abstract":"The split-focus approach has a potential to substantially improve the throughput of coagulation HIFU treatment. A prototype split-focus transducer with two elements at 4.3 MHz combined with a small imaging probe at 6.5 MHz was constructed for transrectal treatment of a prostate. Computer simulation predicted that a coagulation volume approximately three times larger than single-spot focus would be obtained with split focus. Swine liver lobes were intraoperatively insonated for 4 s at a peak intensity of 850 W/cm/sup 2/. A lesion of coagulative necrosis three to six times larger than single-spot focus in volume was formed with the split focus. A canine prostate was then transrectally treated. A cavity, 0.35-0.45 cm/sup 3/ in volume, was formed with only four shots of split-focus insonation.","PeriodicalId":339424,"journal":{"name":"1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027)","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132506234","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}
Pub Date : 1999-10-17DOI: 10.1109/ULTSYM.1999.849508
R. Seip, B. Adamczyk, D. Rundell
Ultrasonic spectra from a multitude of natural and artificial sounds in the interior of an automobile environment under various driving conditions are measured. In addition, over 60000 ultrasonic echoes representing distinct passenger-side vehicle occupancy scenarios were collected with a nominal signal-to-noise ratio (SNR). This information, coupled with animal hearing ranges, is used to determine an optimum operating frequency and SNR for ultrasound-based automotive occupancy sensor (AOS) systems. Ultrasound sensor beamwidth considerations based on vehicle geometry and seat coverage requirements are also presented. Current results indicate that individual transducers operating in the range of 50-120 kHz are immune to most interfering sounds. Geometrical results indicate that transducers with beamwidths between 15-22 degrees provide adequate vehicle interior coverage with minimum interference from doors, cupholders, etc. Finally, AOS performance is not adversely affected over a wide range of SNR's, thus relaxing sensor and electronic design requirements.
{"title":"Use of ultrasound in automotive interior occupancy sensing: optimum frequency, beamwidth, and SNR from empirical data","authors":"R. Seip, B. Adamczyk, D. Rundell","doi":"10.1109/ULTSYM.1999.849508","DOIUrl":"https://doi.org/10.1109/ULTSYM.1999.849508","url":null,"abstract":"Ultrasonic spectra from a multitude of natural and artificial sounds in the interior of an automobile environment under various driving conditions are measured. In addition, over 60000 ultrasonic echoes representing distinct passenger-side vehicle occupancy scenarios were collected with a nominal signal-to-noise ratio (SNR). This information, coupled with animal hearing ranges, is used to determine an optimum operating frequency and SNR for ultrasound-based automotive occupancy sensor (AOS) systems. Ultrasound sensor beamwidth considerations based on vehicle geometry and seat coverage requirements are also presented. Current results indicate that individual transducers operating in the range of 50-120 kHz are immune to most interfering sounds. Geometrical results indicate that transducers with beamwidths between 15-22 degrees provide adequate vehicle interior coverage with minimum interference from doors, cupholders, etc. Finally, AOS performance is not adversely affected over a wide range of SNR's, thus relaxing sensor and electronic design requirements.","PeriodicalId":339424,"journal":{"name":"1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027)","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134452378","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}
Pub Date : 1999-10-17DOI: 10.1109/ULTSYM.1999.849280
Jcirgen Arendt Jensen, Isabel Rodriguez Lacasa
Modern ultrasound scanners estimate the blood velocity by tracking the movement of the blood scatterers along the ultrasound beam. This is done by emitting pulsed ultrasound fields and finding the shift in position from pulse to pulse by correlating the received signals. Only the velocity component along the beam direction is found, and this is a serious limitation in the current scanners, since most blood vessels are parallel to the skin surface. A method to find the velocity across the vessel has been suggested by Bonnefous (1988). Here a number of parallel receive beams are measured and used in a correlation estimator to find the velocity across the beam. This approach is extended in this paper by making beamforming along the direction of the flow. A fairly broad beam is emitted and the received signal is then focused along a selected direction. This direction can be along the ultrasound beam or across it or in any direction to the beam. The focused lines, thus, follow the flow and a cross-correlation of lines from different pulses can find the movement of the blood particles between pulse emissions and, thus, the blood velocity. The new approach is investigated using the Field II simulation program. Simulations are shown for a parabolic velocity profile for flow-to-beam angles of 30, 45, 60, and 90 degrees using a 64 elements linear array with a center frequency of 3 MHz, a pitch of 0.3 mm, and an element height of 5 mm. The peak velocity in the parabolic flow was 0.5 m/s, and the pulse repetition frequency was 3.5 kHz. Using four pulse-echo lines, the parabolic flow profile was found with a standard deviation of 0.028 m/s at 60 degrees and 0.092 m/s at 90 degrees (transverse to the ultrasound beam), corresponding to accuracies of 5.6% and 18.4%. Using ten lines gave standard deviations of 0.021 m/s and 0.089 m/s, respectively, corresponding to accuracies of 4.2% and 17.8%.
{"title":"Estimation of blood velocity vectors using transverse ultrasound beam focusing and cross-correlation","authors":"Jcirgen Arendt Jensen, Isabel Rodriguez Lacasa","doi":"10.1109/ULTSYM.1999.849280","DOIUrl":"https://doi.org/10.1109/ULTSYM.1999.849280","url":null,"abstract":"Modern ultrasound scanners estimate the blood velocity by tracking the movement of the blood scatterers along the ultrasound beam. This is done by emitting pulsed ultrasound fields and finding the shift in position from pulse to pulse by correlating the received signals. Only the velocity component along the beam direction is found, and this is a serious limitation in the current scanners, since most blood vessels are parallel to the skin surface. A method to find the velocity across the vessel has been suggested by Bonnefous (1988). Here a number of parallel receive beams are measured and used in a correlation estimator to find the velocity across the beam. This approach is extended in this paper by making beamforming along the direction of the flow. A fairly broad beam is emitted and the received signal is then focused along a selected direction. This direction can be along the ultrasound beam or across it or in any direction to the beam. The focused lines, thus, follow the flow and a cross-correlation of lines from different pulses can find the movement of the blood particles between pulse emissions and, thus, the blood velocity. The new approach is investigated using the Field II simulation program. Simulations are shown for a parabolic velocity profile for flow-to-beam angles of 30, 45, 60, and 90 degrees using a 64 elements linear array with a center frequency of 3 MHz, a pitch of 0.3 mm, and an element height of 5 mm. The peak velocity in the parabolic flow was 0.5 m/s, and the pulse repetition frequency was 3.5 kHz. Using four pulse-echo lines, the parabolic flow profile was found with a standard deviation of 0.028 m/s at 60 degrees and 0.092 m/s at 90 degrees (transverse to the ultrasound beam), corresponding to accuracies of 5.6% and 18.4%. Using ten lines gave standard deviations of 0.021 m/s and 0.089 m/s, respectively, corresponding to accuracies of 4.2% and 17.8%.","PeriodicalId":339424,"journal":{"name":"1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027)","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117074518","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}
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