Pub Date : 2000-10-22DOI: 10.1109/ULTSYM.2000.922575
E. P. Yepez, Patrick M. Smith
Surface acoustic wave devices can be used to implement matched filters in direct-sequence code division multiple access systems, where they can provide the equivalent of over 1 Tflop computation power. In particular, they are naturally able to process long sequences employing real-valued components. In this paper, we describe the derivation of families of real-valued sequences that offer the benefits of improved auto-correlation and cross-correlation performance, while offering a larger number of codes than traditional binary sequences.
{"title":"Real-valued DS-CDMA sequences","authors":"E. P. Yepez, Patrick M. Smith","doi":"10.1109/ULTSYM.2000.922575","DOIUrl":"https://doi.org/10.1109/ULTSYM.2000.922575","url":null,"abstract":"Surface acoustic wave devices can be used to implement matched filters in direct-sequence code division multiple access systems, where they can provide the equivalent of over 1 Tflop computation power. In particular, they are naturally able to process long sequences employing real-valued components. In this paper, we describe the derivation of families of real-valued sequences that offer the benefits of improved auto-correlation and cross-correlation performance, while offering a larger number of codes than traditional binary sequences.","PeriodicalId":350384,"journal":{"name":"2000 IEEE Ultrasonics Symposium. Proceedings. An International Symposium (Cat. No.00CH37121)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115639842","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 : 2000-10-22DOI: 10.1109/ULTSYM.2000.921624
E. Konofagou, J. Thierman, K. Hynynen
Similar to other therapeutic methods, ultrasound surgery requires an imaging modality to monitor the extent of tissue damage during treatment. Currently, MRI is considered the gold standard method for monitoring tissue ablation, but it is considered to be costly and restrictive in its applications. In this paper, we considered the method of ultrasound-stimulated acoustic emission that uses two ultrasonic beams at high frequency (MHz) (same as that used for ablation) to locally perturb the tissue by generating a low difference frequency (kHz) radiation force. Recording of the tissue response at several locations yields an image. The amplitude of the tissue response depends on the mechanical and acoustic tissue properties, namely its stiffness and absorption. Those two properties were initially hypothesized to have opposite effects in the response amplitude, i.e., the amplitude should increase with absorption and decrease with stiffness. To check this hypothesis as well as the degree to which those properties influence the response, finite-element simulations of a uniform lesion formed in a homogeneous medium were used. The results show that the hypothesis holds at lower frequencies. At resonance and higher frequencies, those two properties have a synergistic effect on the tissue response to the applied radiation force.
{"title":"Ultrasound surgery monitoring using vibroacoustography-a simulation study","authors":"E. Konofagou, J. Thierman, K. Hynynen","doi":"10.1109/ULTSYM.2000.921624","DOIUrl":"https://doi.org/10.1109/ULTSYM.2000.921624","url":null,"abstract":"Similar to other therapeutic methods, ultrasound surgery requires an imaging modality to monitor the extent of tissue damage during treatment. Currently, MRI is considered the gold standard method for monitoring tissue ablation, but it is considered to be costly and restrictive in its applications. In this paper, we considered the method of ultrasound-stimulated acoustic emission that uses two ultrasonic beams at high frequency (MHz) (same as that used for ablation) to locally perturb the tissue by generating a low difference frequency (kHz) radiation force. Recording of the tissue response at several locations yields an image. The amplitude of the tissue response depends on the mechanical and acoustic tissue properties, namely its stiffness and absorption. Those two properties were initially hypothesized to have opposite effects in the response amplitude, i.e., the amplitude should increase with absorption and decrease with stiffness. To check this hypothesis as well as the degree to which those properties influence the response, finite-element simulations of a uniform lesion formed in a homogeneous medium were used. The results show that the hypothesis holds at lower frequencies. At resonance and higher frequencies, those two properties have a synergistic effect on the tissue response to the applied radiation force.","PeriodicalId":350384,"journal":{"name":"2000 IEEE Ultrasonics Symposium. Proceedings. An International Symposium (Cat. No.00CH37121)","volume":"205 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123057508","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 : 2000-10-22DOI: 10.1109/ULTSYM.2000.921632
H. Ermert, O. Keitmann, R. Oppelt, B. Granz, A. Pesavento, M. Vester, B. Tillig, V. Sander
Ultrasound transmission imaging is an alternative promising modality because unlike x-ray transmission this concept is not ionizing and has a good contrast in tissue imaging. Our concept enables also real time imaging. Earlier designs of transmission cameras with a 2D-array and an acoustic lens suffered from high costs, large size and a limited imaging quality, which finally caused those cameras not to become a commercial product. We developed a novel compact low-cost ultrasound transmission camera. With a center frequency of 3 MHz a resolution of 1 mm in both lateral dimensions was achieved over a field of view of 80/spl times/80 mm/sup 2/. Real time images of moving joints and tendons are displayed with a frame-rate of 25 1/s. The major fields of application are orthopedics, pediatrics and diagnosis of rheumatic arthritis.
{"title":"A new concept for a real-time ultrasound transmission camera","authors":"H. Ermert, O. Keitmann, R. Oppelt, B. Granz, A. Pesavento, M. Vester, B. Tillig, V. Sander","doi":"10.1109/ULTSYM.2000.921632","DOIUrl":"https://doi.org/10.1109/ULTSYM.2000.921632","url":null,"abstract":"Ultrasound transmission imaging is an alternative promising modality because unlike x-ray transmission this concept is not ionizing and has a good contrast in tissue imaging. Our concept enables also real time imaging. Earlier designs of transmission cameras with a 2D-array and an acoustic lens suffered from high costs, large size and a limited imaging quality, which finally caused those cameras not to become a commercial product. We developed a novel compact low-cost ultrasound transmission camera. With a center frequency of 3 MHz a resolution of 1 mm in both lateral dimensions was achieved over a field of view of 80/spl times/80 mm/sup 2/. Real time images of moving joints and tendons are displayed with a frame-rate of 25 1/s. The major fields of application are orthopedics, pediatrics and diagnosis of rheumatic arthritis.","PeriodicalId":350384,"journal":{"name":"2000 IEEE Ultrasonics Symposium. Proceedings. An International Symposium (Cat. No.00CH37121)","volume":"20 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120843182","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 : 2000-10-22DOI: 10.1109/ULTSYM.2000.922613
S. Ben-Khelil, A. Merlen, V.L. Prebrazhensky, P. Pernod
Two non linear mechanisms of amplitude limitation of the supercritical mode of parametric wave phase conjugation are considered for an infinite medium with finite active zone, owing to a 1D numerical simulation. Evolutions of the spatial distribution of the normal stress and temporal form of the conjugate wave are presented for both mechanisms.
{"title":"Nonlinear mode of parametric ultrasonic phase conjugation. Numerical approach","authors":"S. Ben-Khelil, A. Merlen, V.L. Prebrazhensky, P. Pernod","doi":"10.1109/ULTSYM.2000.922613","DOIUrl":"https://doi.org/10.1109/ULTSYM.2000.922613","url":null,"abstract":"Two non linear mechanisms of amplitude limitation of the supercritical mode of parametric wave phase conjugation are considered for an infinite medium with finite active zone, owing to a 1D numerical simulation. Evolutions of the spatial distribution of the normal stress and temporal form of the conjugate wave are presented for both mechanisms.","PeriodicalId":350384,"journal":{"name":"2000 IEEE Ultrasonics Symposium. Proceedings. An International Symposium (Cat. No.00CH37121)","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127540183","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 : 2000-10-22DOI: 10.1109/ULTSYM.2000.922573
D. Penunuri, R. Kommrusch, N. Mellen
The success of SAW technology for RF front end filtering in high performance hand held mobile phones and radios is well demonstrated. The small size, high rejection and relatively low insertion loss which can be achieved using SAW impedance resonators gives this technology a significant advantage over competing approaches. One of the remaining issues for SAW impedance resonator filters has been to further improve the performance margins, particularly in the case of pass band edge insertion loss, in order to reduce average insertion loss and improve manufacturing yield. This paper describes the development of a SAW duplexer component that tunes the response of the Tx filter over a frequency range in order to improve its effective performance. The duplexer is fabricated using multi-layer LTCC technology that permits the easy interconnection of numerous diverse components, including SAW filter die, inductors, transmission lines, capacitors and voltage variable capacitors. The duplexer is designed for the dual-mode AMPS/CDMA cellular system, i.e., for transmission in the band from 824-849 MHz and for reception in the band from 869-894 MHz. The duplexer is packaged in a 9 mm/spl times/10 mm/spl times/2.5 mm form factor, attains 0.8 dB minimum insertion loss in the Tx band and 1.0 dB average insertion loss and provides good return loss in a 50 ohm system. The duplexer can be tuned under software control through the use of external DC voltages which are readily available at the RF board.
{"title":"A tunable SAW duplexer","authors":"D. Penunuri, R. Kommrusch, N. Mellen","doi":"10.1109/ULTSYM.2000.922573","DOIUrl":"https://doi.org/10.1109/ULTSYM.2000.922573","url":null,"abstract":"The success of SAW technology for RF front end filtering in high performance hand held mobile phones and radios is well demonstrated. The small size, high rejection and relatively low insertion loss which can be achieved using SAW impedance resonators gives this technology a significant advantage over competing approaches. One of the remaining issues for SAW impedance resonator filters has been to further improve the performance margins, particularly in the case of pass band edge insertion loss, in order to reduce average insertion loss and improve manufacturing yield. This paper describes the development of a SAW duplexer component that tunes the response of the Tx filter over a frequency range in order to improve its effective performance. The duplexer is fabricated using multi-layer LTCC technology that permits the easy interconnection of numerous diverse components, including SAW filter die, inductors, transmission lines, capacitors and voltage variable capacitors. The duplexer is designed for the dual-mode AMPS/CDMA cellular system, i.e., for transmission in the band from 824-849 MHz and for reception in the band from 869-894 MHz. The duplexer is packaged in a 9 mm/spl times/10 mm/spl times/2.5 mm form factor, attains 0.8 dB minimum insertion loss in the Tx band and 1.0 dB average insertion loss and provides good return loss in a 50 ohm system. The duplexer can be tuned under software control through the use of external DC voltages which are readily available at the RF board.","PeriodicalId":350384,"journal":{"name":"2000 IEEE Ultrasonics Symposium. Proceedings. An International Symposium (Cat. No.00CH37121)","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124764406","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 : 2000-10-22DOI: 10.1109/ULTSYM.2000.922497
D. P. Morgan
For low-loss SAW device applications, a variety of single-phase unidirectional transducers (SPUDT's) have been developed. In particular, the DART, using electrodes of different widths, is well established in practical devices. Alternatively, the FEUDT, introduced by Yamanouchi in 1984, employs floating electrodes to introduce directivity. This paper is concerned with FEUDT's in which the electrodes have constant width and pitch. For these cases the transducer reflection coefficient is governed by electrical effects, and consequently the FEUDT is much less critical of film thickness than the DART. Also, unlike the DART, the FEUDT's are effective on strongly-piezoelectric substrates such as lithium niobate. Recently a new analysis of FEUDT's was reported. This is a simplified method using the quasi-static approximation, which is applicable because reflections would be negligible if all the electrodes were shorted. The FEUDT's obey this condition because they have more than two electrodes per wavelength. In this paper, further investigation of FEUDT's is reported using the same analysis, and a variety of novel FEUDT's with 4,5 and 6 electrodes per wavelength are described. Data are given for the transduction, reflection and capacitance parameters per period, and the relative phases between reflection and transduction which is needed to calculate directivity. In many cases the reflection and transduction centres are easily identified from geometrical considerations. The relative performance of the new FEUDT's is reviewed.
{"title":"Investigation of novel floating-electrode unidirectional SAW transducers (FEUDT's)","authors":"D. P. Morgan","doi":"10.1109/ULTSYM.2000.922497","DOIUrl":"https://doi.org/10.1109/ULTSYM.2000.922497","url":null,"abstract":"For low-loss SAW device applications, a variety of single-phase unidirectional transducers (SPUDT's) have been developed. In particular, the DART, using electrodes of different widths, is well established in practical devices. Alternatively, the FEUDT, introduced by Yamanouchi in 1984, employs floating electrodes to introduce directivity. This paper is concerned with FEUDT's in which the electrodes have constant width and pitch. For these cases the transducer reflection coefficient is governed by electrical effects, and consequently the FEUDT is much less critical of film thickness than the DART. Also, unlike the DART, the FEUDT's are effective on strongly-piezoelectric substrates such as lithium niobate. Recently a new analysis of FEUDT's was reported. This is a simplified method using the quasi-static approximation, which is applicable because reflections would be negligible if all the electrodes were shorted. The FEUDT's obey this condition because they have more than two electrodes per wavelength. In this paper, further investigation of FEUDT's is reported using the same analysis, and a variety of novel FEUDT's with 4,5 and 6 electrodes per wavelength are described. Data are given for the transduction, reflection and capacitance parameters per period, and the relative phases between reflection and transduction which is needed to calculate directivity. In many cases the reflection and transduction centres are easily identified from geometrical considerations. The relative performance of the new FEUDT's is reviewed.","PeriodicalId":350384,"journal":{"name":"2000 IEEE Ultrasonics Symposium. Proceedings. An International Symposium (Cat. No.00CH37121)","volume":"74 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124779584","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 : 2000-10-22DOI: 10.1109/ULTSYM.2000.921503
A. Parr, R. O’Leary, G. Hayward, G. Smillie, A. Rice, P. Smith
This paper describes progress towards the understanding of temperature effects in 1-3 piezoelectric composite transducers, carried out via a combination of experimental investigation and finite element (FE) analysis using the commercially available PZFlex code. The elastic properties and internal absorption of different passive materials are measured using a through transmission ultrasonic technique, with dynamic mechanical thermal analysis and differential scanning calorimetry being employed to evaluate the glass transition behaviour and specific heat capacities, respectively. The fillers are then incorporated into piezoelectric composite devices and the transducer performance measured over a wide temperature range by means of electrical impedance analysis and laser scanning of the active surface. The FE models are employed to predict the temperature distribution within such transducers as a function of constituent material properties and the data is correlated with the experimentally measured characteristics. The influence of glass transition temperature on viscoelastic properties is highlighted, along with the design compromises necessary to ensure effective high power performance.
{"title":"Experimental and theoretical evaluation of the thermal behaviour of 1-3 piezoelectric composite transducers","authors":"A. Parr, R. O’Leary, G. Hayward, G. Smillie, A. Rice, P. Smith","doi":"10.1109/ULTSYM.2000.921503","DOIUrl":"https://doi.org/10.1109/ULTSYM.2000.921503","url":null,"abstract":"This paper describes progress towards the understanding of temperature effects in 1-3 piezoelectric composite transducers, carried out via a combination of experimental investigation and finite element (FE) analysis using the commercially available PZFlex code. The elastic properties and internal absorption of different passive materials are measured using a through transmission ultrasonic technique, with dynamic mechanical thermal analysis and differential scanning calorimetry being employed to evaluate the glass transition behaviour and specific heat capacities, respectively. The fillers are then incorporated into piezoelectric composite devices and the transducer performance measured over a wide temperature range by means of electrical impedance analysis and laser scanning of the active surface. The FE models are employed to predict the temperature distribution within such transducers as a function of constituent material properties and the data is correlated with the experimentally measured characteristics. The influence of glass transition temperature on viscoelastic properties is highlighted, along with the design compromises necessary to ensure effective high power performance.","PeriodicalId":350384,"journal":{"name":"2000 IEEE Ultrasonics Symposium. Proceedings. An International Symposium (Cat. No.00CH37121)","volume":"113 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124903965","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 : 2000-10-22DOI: 10.1109/ULTSYM.2000.921673
L. Sandrin, M. Tanter, D. Cassereau, S. Catheline, M. Fink
We have shown in the past that time-resolved 2D pulsed elastography is a promising technique for characterizing the elasticity of soft tissues. It involves the measurement of the displacements induced by the propagation of a low-frequency (50-200 Hz) pulsed shear wave. An ultrafast ultrasonic imaging system (up to 10,000 frames/s) is used to follow the propagation of the slowly propagating shear wave (celerity /spl sim/4 m/s). A new vibrating device has been developed in which the linear array of transducers is placed between two rods fixed to electromagnetic vibrators. Using this device we observe a linear shear wave front in the imaging area. Furthermore the new system allows for low-frequency shear wave beam forming. The results of inversion algorithms indicate that it is possible to recover the elasticity distribution in tissue mimicking materials.
{"title":"Low-frequency shear wave beam forming in time-resolved 2D pulsed elastography","authors":"L. Sandrin, M. Tanter, D. Cassereau, S. Catheline, M. Fink","doi":"10.1109/ULTSYM.2000.921673","DOIUrl":"https://doi.org/10.1109/ULTSYM.2000.921673","url":null,"abstract":"We have shown in the past that time-resolved 2D pulsed elastography is a promising technique for characterizing the elasticity of soft tissues. It involves the measurement of the displacements induced by the propagation of a low-frequency (50-200 Hz) pulsed shear wave. An ultrafast ultrasonic imaging system (up to 10,000 frames/s) is used to follow the propagation of the slowly propagating shear wave (celerity /spl sim/4 m/s). A new vibrating device has been developed in which the linear array of transducers is placed between two rods fixed to electromagnetic vibrators. Using this device we observe a linear shear wave front in the imaging area. Furthermore the new system allows for low-frequency shear wave beam forming. The results of inversion algorithms indicate that it is possible to recover the elasticity distribution in tissue mimicking materials.","PeriodicalId":350384,"journal":{"name":"2000 IEEE Ultrasonics Symposium. Proceedings. An International Symposium (Cat. No.00CH37121)","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124943588","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 : 2000-10-22DOI: 10.1109/ULTSYM.2000.921617
K. Sunagawa, H. Kanai, M. Tanaka
The arterial wall expands and contracts during one heartbeat. At the beginning of systole, there is a possibility that vibrations on the arterial wall are caused by wall shear stress due to the rapid increase of blood flow. It is well known that crisis of atherosclerosis and rupture of plaque are basically caused by blood pressure and wall shear stress applied to the arterial wall. In the literature, wall shear stress is estimated by computer simulation. However, measurements of arterial wall vibrations in radial and axial directions as well as their relation to blood flow have not been reported yet. In this paper, by steering ultrasonic beams in two directions, the radial and axial components of arterial wall vibrations and blood flow velocity are simultaneously measured along the two directions. The relationship between the arterial wall vibrations and blood flow near the wall is evaluated based on the time-frequency analysis. In in vivo experiments, the method was applied to the carotid artery of a healthy subject. From experimental results, the radial and axial components of the arterial wall vibrations were measured together with the blood flow near the wall. A clear correlation was observed for each direction component of the vibrations and blood flow velocity. Since arterial wall vibration is caused by change in the blood pressure and shear stress applied to the wall due to the blood flow, the above results might be a clue to estimate the shear stress applied to the arterial wall from measurement of both the wall vibrations and blood flow.
{"title":"Simultaneous measurement of blood flow and arterial wall vibrations in radial and axial directions","authors":"K. Sunagawa, H. Kanai, M. Tanaka","doi":"10.1109/ULTSYM.2000.921617","DOIUrl":"https://doi.org/10.1109/ULTSYM.2000.921617","url":null,"abstract":"The arterial wall expands and contracts during one heartbeat. At the beginning of systole, there is a possibility that vibrations on the arterial wall are caused by wall shear stress due to the rapid increase of blood flow. It is well known that crisis of atherosclerosis and rupture of plaque are basically caused by blood pressure and wall shear stress applied to the arterial wall. In the literature, wall shear stress is estimated by computer simulation. However, measurements of arterial wall vibrations in radial and axial directions as well as their relation to blood flow have not been reported yet. In this paper, by steering ultrasonic beams in two directions, the radial and axial components of arterial wall vibrations and blood flow velocity are simultaneously measured along the two directions. The relationship between the arterial wall vibrations and blood flow near the wall is evaluated based on the time-frequency analysis. In in vivo experiments, the method was applied to the carotid artery of a healthy subject. From experimental results, the radial and axial components of the arterial wall vibrations were measured together with the blood flow near the wall. A clear correlation was observed for each direction component of the vibrations and blood flow velocity. Since arterial wall vibration is caused by change in the blood pressure and shear stress applied to the wall due to the blood flow, the above results might be a clue to estimate the shear stress applied to the arterial wall from measurement of both the wall vibrations and blood flow.","PeriodicalId":350384,"journal":{"name":"2000 IEEE Ultrasonics Symposium. Proceedings. An International Symposium (Cat. No.00CH37121)","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125041456","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 : 2000-10-22DOI: 10.1109/ULTSYM.2000.921556
H. Kanai, Y. Koiwa
The heart wall motion is color-coded and displayed by the conventional tissue Doppler imaging (TDI) technique. Myocardial motion, however, exhibits frequency components of at least up to 100 Hertz as found by a phased tracking method. In TDI, only the strong slow movements due to the heartbeat are displayed while the rapid and minute velocity components are not included in the results. In this study, by considering the maximum value of the velocity at the points in the interventricular septum (IVS) or the left-ventricle posterior wall (LV-PW) of the human heart, the number of transmission directions of the ultrasonic pulses should be confirmed to be 10, which is much less than the number employed in TDI. Ultrasonic diagnosis equipment was modified so that the 10 directions of the ultrasonic beams were controlled in real time using a micro-computer. By applying the system, the velocity signals at about 240 points in the IVS and the LV-PW were simultaneously measured for healthy volunteers. During a short period of 35 ms around the end diastole, the velocity signals varied spatially in the heart wall. By applying the method to a patient with aortic stenosis (AS), irregular vibration signals, which correspond to the murmur, can be directly detected. This method offers potential for new diagnostic techniques in cardiac dysfunction.
{"title":"Measurement of high velocity distribution of the myocardium","authors":"H. Kanai, Y. Koiwa","doi":"10.1109/ULTSYM.2000.921556","DOIUrl":"https://doi.org/10.1109/ULTSYM.2000.921556","url":null,"abstract":"The heart wall motion is color-coded and displayed by the conventional tissue Doppler imaging (TDI) technique. Myocardial motion, however, exhibits frequency components of at least up to 100 Hertz as found by a phased tracking method. In TDI, only the strong slow movements due to the heartbeat are displayed while the rapid and minute velocity components are not included in the results. In this study, by considering the maximum value of the velocity at the points in the interventricular septum (IVS) or the left-ventricle posterior wall (LV-PW) of the human heart, the number of transmission directions of the ultrasonic pulses should be confirmed to be 10, which is much less than the number employed in TDI. Ultrasonic diagnosis equipment was modified so that the 10 directions of the ultrasonic beams were controlled in real time using a micro-computer. By applying the system, the velocity signals at about 240 points in the IVS and the LV-PW were simultaneously measured for healthy volunteers. During a short period of 35 ms around the end diastole, the velocity signals varied spatially in the heart wall. By applying the method to a patient with aortic stenosis (AS), irregular vibration signals, which correspond to the murmur, can be directly detected. This method offers potential for new diagnostic techniques in cardiac dysfunction.","PeriodicalId":350384,"journal":{"name":"2000 IEEE Ultrasonics Symposium. Proceedings. An International Symposium (Cat. No.00CH37121)","volume":"98 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123268115","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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