P. van Neer, G. Matte, J. Borsboom, M. Verweij, N. de Jong
For several years, the standard in ultrasound imaging has been second harmonic imaging Recently, a new imaging modality, dubbed super harmonic imaging (SHI), has been proposed. SHI takes advantage of the higher - third to fifth - harmonics produced by either nonlinear propagation or contrast agents. Tissue SHI shows a better suppression of near field artefacts and improved lateral and axial resolutions resulting in images with improved clarity compared to second harmonic imaging. If used with contrast agents SHI produces a higher contrast-to-tissue ratio. To enable SHI with a high dynamic range an array sufficiently sensitive at the frequency up to its fifth harmonic is necessary (bandwidth > 130%). We present the results of custom built test arrays aiming specifically on receive sensitivity and SNR. The initial piezomaterial selection was done using the KLM model. From the selected materials test arrays were built (element size 13 times 0.2 mm2, resonance frequency 4 MHz, no matching layer, backing 5.3 MRayl). A calibrated source generated a pressure pulse, while the test array was located in the far field of the source. From the received pressure wave the element transfer functions and SNR were calculated, after compensation for diffraction and spatial averaging. The receive transfer function and SNR were evaluated on a per element basis. The most sensitive test array had an average peak receive sensitivity of 21 muV/Pa and could detect a long sinusoidal burst with amplitude 1 Pa with 22 dB SNR Using these results a conservative estimate predicts a dynamic range for SHI of 55 dB. These results suggest that in vivo tissue and contrast SHI could be feasible using the current array configuration, which is based on interleaved low and high frequency elements.
{"title":"3F-5 Development of a Phased Array for Tissue and Contrast Super Harmonic Imaging","authors":"P. van Neer, G. Matte, J. Borsboom, M. Verweij, N. de Jong","doi":"10.1109/ULTSYM.2007.61","DOIUrl":"https://doi.org/10.1109/ULTSYM.2007.61","url":null,"abstract":"For several years, the standard in ultrasound imaging has been second harmonic imaging Recently, a new imaging modality, dubbed super harmonic imaging (SHI), has been proposed. SHI takes advantage of the higher - third to fifth - harmonics produced by either nonlinear propagation or contrast agents. Tissue SHI shows a better suppression of near field artefacts and improved lateral and axial resolutions resulting in images with improved clarity compared to second harmonic imaging. If used with contrast agents SHI produces a higher contrast-to-tissue ratio. To enable SHI with a high dynamic range an array sufficiently sensitive at the frequency up to its fifth harmonic is necessary (bandwidth > 130%). We present the results of custom built test arrays aiming specifically on receive sensitivity and SNR. The initial piezomaterial selection was done using the KLM model. From the selected materials test arrays were built (element size 13 times 0.2 mm2, resonance frequency 4 MHz, no matching layer, backing 5.3 MRayl). A calibrated source generated a pressure pulse, while the test array was located in the far field of the source. From the received pressure wave the element transfer functions and SNR were calculated, after compensation for diffraction and spatial averaging. The receive transfer function and SNR were evaluated on a per element basis. The most sensitive test array had an average peak receive sensitivity of 21 muV/Pa and could detect a long sinusoidal burst with amplitude 1 Pa with 22 dB SNR Using these results a conservative estimate predicts a dynamic range for SHI of 55 dB. These results suggest that in vivo tissue and contrast SHI could be feasible using the current array configuration, which is based on interleaved low and high frequency elements.","PeriodicalId":6355,"journal":{"name":"2007 IEEE Ultrasonics Symposium Proceedings","volume":"93 1","pages":"200-203"},"PeriodicalIF":0.0,"publicationDate":"2007-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83845985","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}
In this paper, a new MEMS device that can separate microparticles on-chip by the use of bulk-mode excited membrane vibration is proposed, designed and microfabricated. By starting from the one-dimensional analytical mode of forces acting on particles,the force for ultrasonically separating particles is profoundly studied, and finite element method in ANSYS is used to analyze the vibration modes, the acoustic field and flow field in the microdevice due to the membrane vibration. With these analyses, we obtain the ultrasonic radiation force acting on different kinds of particles in the water, blood plasma and milk medium when the microdevice vibrates at different frequencies and then study their separation.
{"title":"P2E-2 Study of Particles Separation in the Ultrasonic Microdevice","authors":"Hui Yang, Hang Guo","doi":"10.1109/ULTSYM.2007.401","DOIUrl":"https://doi.org/10.1109/ULTSYM.2007.401","url":null,"abstract":"In this paper, a new MEMS device that can separate microparticles on-chip by the use of bulk-mode excited membrane vibration is proposed, designed and microfabricated. By starting from the one-dimensional analytical mode of forces acting on particles,the force for ultrasonically separating particles is profoundly studied, and finite element method in ANSYS is used to analyze the vibration modes, the acoustic field and flow field in the microdevice due to the membrane vibration. With these analyses, we obtain the ultrasonic radiation force acting on different kinds of particles in the water, blood plasma and milk medium when the microdevice vibrates at different frequencies and then study their separation.","PeriodicalId":6355,"journal":{"name":"2007 IEEE Ultrasonics Symposium Proceedings","volume":"18 1","pages":"1594-1597"},"PeriodicalIF":0.0,"publicationDate":"2007-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79195851","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}
C. Jia, R. Olafsson, K. Kim, R. Witte, S.-W. Huang, T. Kolias, J. Rubin, W. Weitzel, C. Deng, M. O’Donnell
Ultrasound strain and strain rate imaging have been proposed to detect myocardial muscle viability and contractility change. However, it's not easy to control experimental parameters and acquire high SNR data during in-vivo animal experiments. To address this, we performed 2D cardiac elasticity imaging on a well-controlled isolated retroperfused rabbit heart paced through the apex. The excitation-contraction decoupler, 2,3-butanedione monoxime (BDM) was used to optimize the maximum strain given frame acquisition rate, reducing the decorrelation due to excessive frame-to-frame strain. Under a local animal protocol, a heart was harvested from an anesthetized New Zealand White rabbit and prepared using a Langendorff preparation. Modified Oxygenated (95% 02 5% CO2) Krebs- Henseleit (K-H) buffer (PH 7.4, 37 degC) solution was retroperfused through the aorta. The heart was paced through the apex with electrodes at 3 Hz. The internal left ventricle (LV) pressure was recorded using a pressure meter connected to a water-filled latex balloon placed in the LV. The ECG signal was simultaneously recorded. Two linear array connected to a commercial US scanner (Sonix RP, Ultrasonix, Richmond, BC, Canada) were used to acquire RF data. The pacing signal, US RF, ECG and LV pressure data capturing were all synchronized using an field programmable gate array (FPGA) chip (ezFPGA-C6-6, Dallas Logic, Piano, TX, USA). All these data were acquired before administering, during perfusion and after flushing BDM without/with the ligation of left anterior decending (LAD) artery At each data acquisition point, US RF data were acquired over two heart cycles (41 frames/cycle). 2D speckle tracking was applied to estimate displacement and strain. In this experiment, principal stretches were also derived using tracking results from two probes with resolution about 1.25 mm along its own axial direction. The principal stretches were compared for the normal heart and heart with ischemia or MI produced by LAD ligation. The isolated rabbit heart combined with BDM (2 mM) provided a well-controlled experimental environment for cardiac strain imaging with a virtually high frame acquisition rate. By comparing the synchronized pacing signal, LV pressure, ECG signal, and principal stretch, we were able to monitor and verify the local cardiac contractility referenced to the electrical stimulation.
{"title":"9A-2 Controlled 2D Cardiac Elasticity Imaging on an Isolated Perfused Rabbit Heart","authors":"C. Jia, R. Olafsson, K. Kim, R. Witte, S.-W. Huang, T. Kolias, J. Rubin, W. Weitzel, C. Deng, M. O’Donnell","doi":"10.1109/ULTSYM.2007.191","DOIUrl":"https://doi.org/10.1109/ULTSYM.2007.191","url":null,"abstract":"Ultrasound strain and strain rate imaging have been proposed to detect myocardial muscle viability and contractility change. However, it's not easy to control experimental parameters and acquire high SNR data during in-vivo animal experiments. To address this, we performed 2D cardiac elasticity imaging on a well-controlled isolated retroperfused rabbit heart paced through the apex. The excitation-contraction decoupler, 2,3-butanedione monoxime (BDM) was used to optimize the maximum strain given frame acquisition rate, reducing the decorrelation due to excessive frame-to-frame strain. Under a local animal protocol, a heart was harvested from an anesthetized New Zealand White rabbit and prepared using a Langendorff preparation. Modified Oxygenated (95% 02 5% CO2) Krebs- Henseleit (K-H) buffer (PH 7.4, 37 degC) solution was retroperfused through the aorta. The heart was paced through the apex with electrodes at 3 Hz. The internal left ventricle (LV) pressure was recorded using a pressure meter connected to a water-filled latex balloon placed in the LV. The ECG signal was simultaneously recorded. Two linear array connected to a commercial US scanner (Sonix RP, Ultrasonix, Richmond, BC, Canada) were used to acquire RF data. The pacing signal, US RF, ECG and LV pressure data capturing were all synchronized using an field programmable gate array (FPGA) chip (ezFPGA-C6-6, Dallas Logic, Piano, TX, USA). All these data were acquired before administering, during perfusion and after flushing BDM without/with the ligation of left anterior decending (LAD) artery At each data acquisition point, US RF data were acquired over two heart cycles (41 frames/cycle). 2D speckle tracking was applied to estimate displacement and strain. In this experiment, principal stretches were also derived using tracking results from two probes with resolution about 1.25 mm along its own axial direction. The principal stretches were compared for the normal heart and heart with ischemia or MI produced by LAD ligation. The isolated rabbit heart combined with BDM (2 mM) provided a well-controlled experimental environment for cardiac strain imaging with a virtually high frame acquisition rate. By comparing the synchronized pacing signal, LV pressure, ECG signal, and principal stretch, we were able to monitor and verify the local cardiac contractility referenced to the electrical stimulation.","PeriodicalId":6355,"journal":{"name":"2007 IEEE Ultrasonics Symposium Proceedings","volume":"61 1","pages":"745-748"},"PeriodicalIF":0.0,"publicationDate":"2007-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79487208","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}
The poro-viscoelastic (PVE) response of tissues or hydropolymers may be accurately modeled with as few as three parameters using the Kelvin-Voigt fractional derivative approach. We propose to image these parameters for simulated and experimental imaging phantoms and to analyze their values in different media. We show that each parameter can be explained in terms of stiffness and fluidity of the material and use the parameter images to differentiate two simulated imaging phantoms with apparently similar PVE properties.
{"title":"P0-6 Kelvin-Voigt Fractional Derivative Approach Reduces Parameter Space for Elasticity Imaging","authors":"C. Coussot, S. Kalyanam, R. Yapp, M. Insana","doi":"10.1109/ULTSYM.2007.303","DOIUrl":"https://doi.org/10.1109/ULTSYM.2007.303","url":null,"abstract":"The poro-viscoelastic (PVE) response of tissues or hydropolymers may be accurately modeled with as few as three parameters using the Kelvin-Voigt fractional derivative approach. We propose to image these parameters for simulated and experimental imaging phantoms and to analyze their values in different media. We show that each parameter can be explained in terms of stiffness and fluidity of the material and use the parameter images to differentiate two simulated imaging phantoms with apparently similar PVE properties.","PeriodicalId":6355,"journal":{"name":"2007 IEEE Ultrasonics Symposium Proceedings","volume":"21 1","pages":"1204-1207"},"PeriodicalIF":0.0,"publicationDate":"2007-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83267843","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}
The progressive dynamic focusing correction technique (PROFOC) has been recently proposed as an efficient methodology to beamformer implementation. A single bit per focus allows determining the sampling instant at every array channel with high timing resolution to get wide dynamic range images. However, this requires a separate sampling clock generator for every array element, while most state of the art multi-channel A/D converters share a common clock signal. This work proposes a method to use the PROFOC technique with these devices. On the other hand, the performance of the new technique in NDE applications is assessed. The evaluation is carried out using static and PROFOC dynamic focusing, with foci at regular or dynamically varying intervals.
{"title":"P2D-5 The Progressive Dynamic Focusing Correction Technique in NDE","authors":"J. Camacho, M. Parrilla, A. Ibáñez, C. Fritsch","doi":"10.1109/ULTSYM.2007.399","DOIUrl":"https://doi.org/10.1109/ULTSYM.2007.399","url":null,"abstract":"The progressive dynamic focusing correction technique (PROFOC) has been recently proposed as an efficient methodology to beamformer implementation. A single bit per focus allows determining the sampling instant at every array channel with high timing resolution to get wide dynamic range images. However, this requires a separate sampling clock generator for every array element, while most state of the art multi-channel A/D converters share a common clock signal. This work proposes a method to use the PROFOC technique with these devices. On the other hand, the performance of the new technique in NDE applications is assessed. The evaluation is carried out using static and PROFOC dynamic focusing, with foci at regular or dynamically varying intervals.","PeriodicalId":6355,"journal":{"name":"2007 IEEE Ultrasonics Symposium Proceedings","volume":"77 1 1","pages":"1586-1589"},"PeriodicalIF":0.0,"publicationDate":"2007-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83403626","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}
Conventional linear arrays can be used for 3D ultrasound imaging, by moving the array in the elevation direction and stacking the planes in a volume. The point spread function (PSF) is larger in the elevation plane, as the aperture is smaller and has a fixed elevation focus. Resolution improvements in elevation can be achieved by applying synthetic aperture (SA) focusing to the beamformed in-plane RF-data. The method uses a virtual source (VS) placed at the elevation focus for post-beamforming. This has previously been done in two steps, in plane focusing followed by SA post-focusing in elevation, because of a lack of a simple expression for the exact time of flight (ToF). This paper presents a new method for calculating the ToF for a 3D case in a single step using a spherical defocused emission from a linear array. The method is evaluated using both simulated data obtained by Field II and phantom measurements using the RASMUS experimental scanner. For the simulation, scatterers were placed from 20 to 120 mm of depth. A point and a cyst phantom were scanned by translating a 7 MHz linear array in the elevation direction. For a point placed at (25,8, 75) mm relative to the transducer, the mean error between the calculated and estimated ToF is 0.0129 mus (0.09A), and the standard deviation of the ToF error is 0.0049A. SA focusing improves both contrast and resolution. For simulated scatterers at depths of 40 and 70 mm the FWHM is 83.6% and 46.8% of the FWHM without elevation SA focusing. The main-lobe to side-lobe energy ratio (MLSLR) for the scatterers is 32.3 dB and 29.1 dB. The measurement of a PSF phantom at a depth of 65 mm shows a relative FWHM of 27.8%. For an elevation sampling distance of 0.63 mm, the MLSLR for the two simulated scatterers is 26.4 dB and 27.9 dB. For the point phantom the MLSLR is 16.3 dB. If the elevation sampling distance is increased to 0.99 mm, the two simulated scatterers have a MLSLR of 21.1 dB and 15.8 dB respectively, and the point phantom has an MLSLR of 5.2 dB. The cyst phantom shows an improvement of 5.8 dB in contrast to noise ratio, for a 4 mm cyst, when elevation focusing is applied.
{"title":"4B-4 Precise Time-of-Flight Calculation For 3D Synthetic Aperture Focusing","authors":"H. Andresen, S. Nikolov, J. A. Jensen","doi":"10.1109/ULTSYM.2007.67","DOIUrl":"https://doi.org/10.1109/ULTSYM.2007.67","url":null,"abstract":"Conventional linear arrays can be used for 3D ultrasound imaging, by moving the array in the elevation direction and stacking the planes in a volume. The point spread function (PSF) is larger in the elevation plane, as the aperture is smaller and has a fixed elevation focus. Resolution improvements in elevation can be achieved by applying synthetic aperture (SA) focusing to the beamformed in-plane RF-data. The method uses a virtual source (VS) placed at the elevation focus for post-beamforming. This has previously been done in two steps, in plane focusing followed by SA post-focusing in elevation, because of a lack of a simple expression for the exact time of flight (ToF). This paper presents a new method for calculating the ToF for a 3D case in a single step using a spherical defocused emission from a linear array. The method is evaluated using both simulated data obtained by Field II and phantom measurements using the RASMUS experimental scanner. For the simulation, scatterers were placed from 20 to 120 mm of depth. A point and a cyst phantom were scanned by translating a 7 MHz linear array in the elevation direction. For a point placed at (25,8, 75) mm relative to the transducer, the mean error between the calculated and estimated ToF is 0.0129 mus (0.09A), and the standard deviation of the ToF error is 0.0049A. SA focusing improves both contrast and resolution. For simulated scatterers at depths of 40 and 70 mm the FWHM is 83.6% and 46.8% of the FWHM without elevation SA focusing. The main-lobe to side-lobe energy ratio (MLSLR) for the scatterers is 32.3 dB and 29.1 dB. The measurement of a PSF phantom at a depth of 65 mm shows a relative FWHM of 27.8%. For an elevation sampling distance of 0.63 mm, the MLSLR for the two simulated scatterers is 26.4 dB and 27.9 dB. For the point phantom the MLSLR is 16.3 dB. If the elevation sampling distance is increased to 0.99 mm, the two simulated scatterers have a MLSLR of 21.1 dB and 15.8 dB respectively, and the point phantom has an MLSLR of 5.2 dB. The cyst phantom shows an improvement of 5.8 dB in contrast to noise ratio, for a 4 mm cyst, when elevation focusing is applied.","PeriodicalId":6355,"journal":{"name":"2007 IEEE Ultrasonics Symposium Proceedings","volume":"57 1","pages":"224-227"},"PeriodicalIF":0.0,"publicationDate":"2007-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88581391","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}
M. Bae, Baeksop Kim, M. Jeong, Jeong-Ho Ham, Dae-Young Kim, Wooyoul Lee, Han-Woo Lee
In synthetic aperture imaging (SAI), it is well known fact that focusing quality will be degraded without estimation and compensation of the target movement. Various methods are available for compensation of the target movement. In this paper, simpler and more robust computational method compare to the conventional method will be presented. Presented method combines autocorrelation method of conventional two dimensional- tissue Doppler imaging (2D-TDI) with SAI, only the transmit sequence is appropriately changed. Computer simulation and the phantom experiment are used to show effectiveness of the presented method.
{"title":"P2B-3 A New Motion Estimation and Compensation Method for Real-Time Ultrasonic Synthetic Aperture Imaging","authors":"M. Bae, Baeksop Kim, M. Jeong, Jeong-Ho Ham, Dae-Young Kim, Wooyoul Lee, Han-Woo Lee","doi":"10.1109/ULTSYM.2007.380","DOIUrl":"https://doi.org/10.1109/ULTSYM.2007.380","url":null,"abstract":"In synthetic aperture imaging (SAI), it is well known fact that focusing quality will be degraded without estimation and compensation of the target movement. Various methods are available for compensation of the target movement. In this paper, simpler and more robust computational method compare to the conventional method will be presented. Presented method combines autocorrelation method of conventional two dimensional- tissue Doppler imaging (2D-TDI) with SAI, only the transmit sequence is appropriately changed. Computer simulation and the phantom experiment are used to show effectiveness of the presented method.","PeriodicalId":6355,"journal":{"name":"2007 IEEE Ultrasonics Symposium Proceedings","volume":"8 1","pages":"1511-1513"},"PeriodicalIF":0.0,"publicationDate":"2007-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87323930","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}
K. Kokkonen, S. Benchabane, A. Khelif, V. Laude, M. Kaivola
Heterodyne laser interferometer has been used to directly study surface acoustic wave interaction with a two- dimensional phononic crystal. Acoustic waves are launched by interdigital transducers towards a square lattice of holes etched into the piezoelectric substrate. Interferometer measurements performed at frequencies below, within and above the expected band gap frequency range provide direct observation of the wave interaction with the phononic crystal, revealing anisotropic scattering into higher diffraction orders depending on the apparent grating pitch at the boundary between the phononic crystal and free surface. Furthermore, the measurements also confirm the existence of an elastic band gap, in accordance with previous electrical measurements and theoretical predictions.
{"title":"P3J-1 Direct Observation of Surface Acoustic Wave Interaction with a Phononic Crystal","authors":"K. Kokkonen, S. Benchabane, A. Khelif, V. Laude, M. Kaivola","doi":"10.1109/ULTSYM.2007.478","DOIUrl":"https://doi.org/10.1109/ULTSYM.2007.478","url":null,"abstract":"Heterodyne laser interferometer has been used to directly study surface acoustic wave interaction with a two- dimensional phononic crystal. Acoustic waves are launched by interdigital transducers towards a square lattice of holes etched into the piezoelectric substrate. Interferometer measurements performed at frequencies below, within and above the expected band gap frequency range provide direct observation of the wave interaction with the phononic crystal, revealing anisotropic scattering into higher diffraction orders depending on the apparent grating pitch at the boundary between the phononic crystal and free surface. Furthermore, the measurements also confirm the existence of an elastic band gap, in accordance with previous electrical measurements and theoretical predictions.","PeriodicalId":6355,"journal":{"name":"2007 IEEE Ultrasonics Symposium Proceedings","volume":"16 1","pages":"1901-1904"},"PeriodicalIF":0.0,"publicationDate":"2007-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87296716","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}
N. Okada, K. Higuchi, K. Kobayashi, M. Ito, M. Takabe, M. Otonari, D. Akai, K. Sawada, M. Ishida
A piezoelectric ultrasonic hydrophone array was fabricated using epitaxial lead zirconate titanate, Pb(Zx, Ti1-x)O3 (PZT) thin film grown on epitaxial SrRuO3/Pt/gamma-Al2O3/Si substrates. PZT film with 3 mum in thickness was prepared by sol- gel method. An experimental ultrasonic hydrophone array measurement system, a one dimensional (1-D) array of 10 elements and a two dimensional (2D) array of 4 times 4 elements have been developed to evaluate the hydrophone array system performance. In this paper, we describe the fabrication process of the hydrophone arrays and the data acquisition system. The beam direction was estimated and the B-mode image was reconstructed to evaluate the array sensitivity. The potential applications for this hydrophone array are discussed.
{"title":"P1J-3 Evaluation of 2D Hydrophone Array System Using Epitaxial PZT Thin Film Grown on Epitaxial GAMMA-Al2O3/Si Substrate","authors":"N. Okada, K. Higuchi, K. Kobayashi, M. Ito, M. Takabe, M. Otonari, D. Akai, K. Sawada, M. Ishida","doi":"10.1109/ULTSYM.2007.366","DOIUrl":"https://doi.org/10.1109/ULTSYM.2007.366","url":null,"abstract":"A piezoelectric ultrasonic hydrophone array was fabricated using epitaxial lead zirconate titanate, Pb(Zx, Ti1-x)O3 (PZT) thin film grown on epitaxial SrRuO3/Pt/gamma-Al2O3/Si substrates. PZT film with 3 mum in thickness was prepared by sol- gel method. An experimental ultrasonic hydrophone array measurement system, a one dimensional (1-D) array of 10 elements and a two dimensional (2D) array of 4 times 4 elements have been developed to evaluate the hydrophone array system performance. In this paper, we describe the fabrication process of the hydrophone arrays and the data acquisition system. The beam direction was estimated and the B-mode image was reconstructed to evaluate the array sensitivity. The potential applications for this hydrophone array are discussed.","PeriodicalId":6355,"journal":{"name":"2007 IEEE Ultrasonics Symposium Proceedings","volume":"29 1","pages":"1456-1459"},"PeriodicalIF":0.0,"publicationDate":"2007-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84768094","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}
S. Sethuraman, Bo Wang, Silvio H. Litovsky, J. Amirian, R. Smalling, S. Emelianov
Intravascular photoacoustic (IVPA) imaging has the potential to detect atherosclerotic plaques. Previously, we obtained IVPA images using a 532 nm pulsed laser and a 40 MHz intravascular ultrasound (IVUS) imaging catheter. The optical absorption of light by the plaque components was used as a contrast mechanism helpful in detecting the plaque. However, plaque differentiation requires a method to remotely assess plaque composition. We hypothesized that plaque characterization can be performed by monitoring the changes in photoacoustic response with the change in laser excitation wavelength. In this preliminary study, we performed spectroscopic IVPA imaging to analyze the change in the photoacoustic response of the aortic tissue (a rabbit aorta with plaque and a control aorta) using different laser excitation wavelengths. Specifically, we perform IVPA imaging at multiple wavelengths within 680-900 nm range. The slope of the spectral change in photoacoustic response was computed between selected wavelengths to produce a spectroscopic IVPA image. The results of our study suggest the ability of the multi-wavelength IVPA imaging to identify and differentiate the fibrous, lipid and blood components of the atherosclerotic plaque.
{"title":"P0-2 Spectroscopic Intravascular Photoacoustic Imaging","authors":"S. Sethuraman, Bo Wang, Silvio H. Litovsky, J. Amirian, R. Smalling, S. Emelianov","doi":"10.1109/ULTSYM.2007.299","DOIUrl":"https://doi.org/10.1109/ULTSYM.2007.299","url":null,"abstract":"Intravascular photoacoustic (IVPA) imaging has the potential to detect atherosclerotic plaques. Previously, we obtained IVPA images using a 532 nm pulsed laser and a 40 MHz intravascular ultrasound (IVUS) imaging catheter. The optical absorption of light by the plaque components was used as a contrast mechanism helpful in detecting the plaque. However, plaque differentiation requires a method to remotely assess plaque composition. We hypothesized that plaque characterization can be performed by monitoring the changes in photoacoustic response with the change in laser excitation wavelength. In this preliminary study, we performed spectroscopic IVPA imaging to analyze the change in the photoacoustic response of the aortic tissue (a rabbit aorta with plaque and a control aorta) using different laser excitation wavelengths. Specifically, we perform IVPA imaging at multiple wavelengths within 680-900 nm range. The slope of the spectral change in photoacoustic response was computed between selected wavelengths to produce a spectroscopic IVPA image. The results of our study suggest the ability of the multi-wavelength IVPA imaging to identify and differentiate the fibrous, lipid and blood components of the atherosclerotic plaque.","PeriodicalId":6355,"journal":{"name":"2007 IEEE Ultrasonics Symposium Proceedings","volume":"76 1","pages":"1188-1191"},"PeriodicalIF":0.0,"publicationDate":"2007-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86656913","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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