Pub Date : 1997-10-05DOI: 10.1109/ULTSYM.1997.663317
J. Talman, G. Lockwood
The development of transducer arrays for high frequency medical imaging is complicated by the extremely small dimensions of the array elements. For example, a 50 MHz linear phased array requires a center to center element spacing of only 15 /spl mu/m. Fabricating an array with these dimensions is difficult using conventional technology. A split aperture design that permits much larger element spacing (3-4 times) while avoiding the formation of grating lobes is described. The 3D radiation pattern of a 2.0/spl times/1.4 mm, 50 MHz split aperture phased array with 32 transmit elements and 32 receive elements was evaluated theoretically. The array was designed using a passive lens in the elevation direction focussed at 7.5 mm and a fixed transmit focal distance in the azimuthal direction focussed at 5.0 mm. Grating lobes in the azimuthal direction were suppressed by 60 dB over the range from 5.0 to 9.0 mm.
{"title":"Theoretical evaluation of a 50 MHz split aperture linear phased array","authors":"J. Talman, G. Lockwood","doi":"10.1109/ULTSYM.1997.663317","DOIUrl":"https://doi.org/10.1109/ULTSYM.1997.663317","url":null,"abstract":"The development of transducer arrays for high frequency medical imaging is complicated by the extremely small dimensions of the array elements. For example, a 50 MHz linear phased array requires a center to center element spacing of only 15 /spl mu/m. Fabricating an array with these dimensions is difficult using conventional technology. A split aperture design that permits much larger element spacing (3-4 times) while avoiding the formation of grating lobes is described. The 3D radiation pattern of a 2.0/spl times/1.4 mm, 50 MHz split aperture phased array with 32 transmit elements and 32 receive elements was evaluated theoretically. The array was designed using a passive lens in the elevation direction focussed at 7.5 mm and a fixed transmit focal distance in the azimuthal direction focussed at 5.0 mm. Grating lobes in the azimuthal direction were suppressed by 60 dB over the range from 5.0 to 9.0 mm.","PeriodicalId":6369,"journal":{"name":"1997 IEEE Ultrasonics Symposium Proceedings. An International Symposium (Cat. No.97CH36118)","volume":"24 1","pages":"1675-1678 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1997-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83225552","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 : 1997-10-05DOI: 10.1109/ULTSYM.1997.663348
M. Tanter, J. Thomas, M. Fink
To focus ultrasonic waves in inhomogeneous media using a phased array, one has to calculate the optimal set of signals (for monochromatic waves, amplitude and phase (D.R. Jackson and D.R. Dowling, 1991)) to be applied on the transducers of the array. The solution obtained by Time Reversal Processing (TRP) corresponds to the spatial and temporal filter matched to an initial source available in the medium. However, this process doesn't ensure that the field amplitude at other locations is as small as possible. The authors have illustrated this problem previously using the example of focusing through the human skull, which is an absorbing medium. The authors found that in order to obtain good focusing, it is necessary to add to the time reversal process an amplitude compensation that takes into account absorption. Another approach consists in using an entire array of transducers on both sides of the skull. The authors measure and compare the focal quality obtained in the different cases: matched filter, inverse filter and amplitude compensation combined with time reversal.
{"title":"Comparison between time reversal focusing in absorbing medium and inverse filtering","authors":"M. Tanter, J. Thomas, M. Fink","doi":"10.1109/ULTSYM.1997.663348","DOIUrl":"https://doi.org/10.1109/ULTSYM.1997.663348","url":null,"abstract":"To focus ultrasonic waves in inhomogeneous media using a phased array, one has to calculate the optimal set of signals (for monochromatic waves, amplitude and phase (D.R. Jackson and D.R. Dowling, 1991)) to be applied on the transducers of the array. The solution obtained by Time Reversal Processing (TRP) corresponds to the spatial and temporal filter matched to an initial source available in the medium. However, this process doesn't ensure that the field amplitude at other locations is as small as possible. The authors have illustrated this problem previously using the example of focusing through the human skull, which is an absorbing medium. The authors found that in order to obtain good focusing, it is necessary to add to the time reversal process an amplitude compensation that takes into account absorption. Another approach consists in using an entire array of transducers on both sides of the skull. The authors measure and compare the focal quality obtained in the different cases: matched filter, inverse filter and amplitude compensation combined with time reversal.","PeriodicalId":6369,"journal":{"name":"1997 IEEE Ultrasonics Symposium Proceedings. An International Symposium (Cat. No.97CH36118)","volume":"2 1","pages":"1741-1745 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1997-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81441154","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 : 1997-10-05DOI: 10.1109/ULTSYM.1997.661731
C. Oakley, B. Pazol, D. Powell, M.R. LaBree, K. M. Gabriel, L. Koornneef, M. Callahan, G. Wojcik
Composite piezoelectric materials with a 1-3 connectivity are almost ideal for transducer applications where the width-to-thickness aspect ratio of individual elements is in the range of about 0.7 to 10 (the range required for most 1.5-D array applications). The high anisotropy of the composite enhances coupling in the thickness mode but reduces the coupling and damps vibrations in the lateral direction. One major drawback of these composites is that the reduced volume fraction of ceramic results in elements with a low capacitance and high electrical impedance making the small elements difficult to drive. A solution to this drawback is to stack the composite material in n layers and connect the layers in parallel to achieve the n/sup 2/ reduction in electrical impedance. This paper presents a method for making stacked composite material and using them in 1.5-D arrays. This method consists of stacking 2-2 composites with the strips running in the scan-plane of the proposed array and creating the 1-3 structure during array construction by using standard dicing and subdicing techniques of the acoustic stack. Measured results from stacked composites made by both the dice-and-fill and injection mold-and-fill methods are presented and compared. The consequences of misalignment are shown and analyzed. The cost implications for both dice-and-fill and injection mold-and-fill methods are discussed.
{"title":"Stacked composite piezoelectric materials for 1.5-D arrays","authors":"C. Oakley, B. Pazol, D. Powell, M.R. LaBree, K. M. Gabriel, L. Koornneef, M. Callahan, G. Wojcik","doi":"10.1109/ULTSYM.1997.661731","DOIUrl":"https://doi.org/10.1109/ULTSYM.1997.661731","url":null,"abstract":"Composite piezoelectric materials with a 1-3 connectivity are almost ideal for transducer applications where the width-to-thickness aspect ratio of individual elements is in the range of about 0.7 to 10 (the range required for most 1.5-D array applications). The high anisotropy of the composite enhances coupling in the thickness mode but reduces the coupling and damps vibrations in the lateral direction. One major drawback of these composites is that the reduced volume fraction of ceramic results in elements with a low capacitance and high electrical impedance making the small elements difficult to drive. A solution to this drawback is to stack the composite material in n layers and connect the layers in parallel to achieve the n/sup 2/ reduction in electrical impedance. This paper presents a method for making stacked composite material and using them in 1.5-D arrays. This method consists of stacking 2-2 composites with the strips running in the scan-plane of the proposed array and creating the 1-3 structure during array construction by using standard dicing and subdicing techniques of the acoustic stack. Measured results from stacked composites made by both the dice-and-fill and injection mold-and-fill methods are presented and compared. The consequences of misalignment are shown and analyzed. The cost implications for both dice-and-fill and injection mold-and-fill methods are discussed.","PeriodicalId":6369,"journal":{"name":"1997 IEEE Ultrasonics Symposium Proceedings. An International Symposium (Cat. No.97CH36118)","volume":"61 1","pages":"923-926 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1997-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81125841","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 : 1997-10-05DOI: 10.1109/ULTSYM.1997.663035
G. Ostermayer, A. Pohl, L. Reindl, F. Seifert
In this paper we present a method of solving the problem of access to more than one passive surface acoustic wave (SAW) sensor in the range of a single interrogation system. The sensor informations of the SAW sensors are evaluated almost simultaneously by use of the correlation property of BPSK-coded sensors. We show the principal concept, mathematical simulations, numerical estimations and finally an overview of the design of such a SAW sensor system.
{"title":"Multiple access to SAW sensors using matched filter properties","authors":"G. Ostermayer, A. Pohl, L. Reindl, F. Seifert","doi":"10.1109/ULTSYM.1997.663035","DOIUrl":"https://doi.org/10.1109/ULTSYM.1997.663035","url":null,"abstract":"In this paper we present a method of solving the problem of access to more than one passive surface acoustic wave (SAW) sensor in the range of a single interrogation system. The sensor informations of the SAW sensors are evaluated almost simultaneously by use of the correlation property of BPSK-coded sensors. We show the principal concept, mathematical simulations, numerical estimations and finally an overview of the design of such a SAW sensor system.","PeriodicalId":6369,"journal":{"name":"1997 IEEE Ultrasonics Symposium Proceedings. An International Symposium (Cat. No.97CH36118)","volume":"17 1","pages":"339-342 vol.1"},"PeriodicalIF":0.0,"publicationDate":"1997-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89595926","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 : 1997-10-05DOI: 10.1109/ULTSYM.1997.663096
R. K. Ing, B.F. Pouet, S. Krishnaswamy, D. Royer
The advantages of ultrasonic remote detection using a heterodyne photorefractive interferometer are demonstrated. The speckle nature of the light reflected by a rough surface (or after propagation through a multimode fiber) does not degrade the interferometer sensitivity. Thanks to the process of wave mixing in photorefractive crystals, this interferometer has a large etendue. Furthermore, the heterodyne detection provides an absolute measurement of the ultrasonic amplitudes. We investigate the influence of an applied ac electric field. Two photorefractive crystals, undoped BSO and BSO:Cr, which have different optical characteristics are compared. Finally, examples of application to NDE are demonstrated.
{"title":"Adaptive heterodyne photorefractive interferometer for ultrasound detection: optimization and application","authors":"R. K. Ing, B.F. Pouet, S. Krishnaswamy, D. Royer","doi":"10.1109/ULTSYM.1997.663096","DOIUrl":"https://doi.org/10.1109/ULTSYM.1997.663096","url":null,"abstract":"The advantages of ultrasonic remote detection using a heterodyne photorefractive interferometer are demonstrated. The speckle nature of the light reflected by a rough surface (or after propagation through a multimode fiber) does not degrade the interferometer sensitivity. Thanks to the process of wave mixing in photorefractive crystals, this interferometer has a large etendue. Furthermore, the heterodyne detection provides an absolute measurement of the ultrasonic amplitudes. We investigate the influence of an applied ac electric field. Two photorefractive crystals, undoped BSO and BSO:Cr, which have different optical characteristics are compared. Finally, examples of application to NDE are demonstrated.","PeriodicalId":6369,"journal":{"name":"1997 IEEE Ultrasonics Symposium Proceedings. An International Symposium (Cat. No.97CH36118)","volume":"157 1","pages":"613-616 vol.1"},"PeriodicalIF":0.0,"publicationDate":"1997-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86343543","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 : 1997-10-05DOI: 10.1109/ULTSYM.1997.663073
T. Hesjedal, E. Chilla, H.-J. Frohlich
In this paper we report the observation of surface acoustic waves using a scanning tunneling microscope (STM). As the STM control electronics have a bandwidth limit in the kHz range, SAWs at typical frequencies of MHz to GHz cause a loss of contrast which can be clearly seen on an atomic scale. In order to access the amplitude and phase of a SAW, we introduced a heterodyning type STM, the scanning acoustic tunneling microscope (SATM). Contrary to the STM technique, the SATM measures snapshots of the state of oscillation. On the nanometer scale, two contributions to the phase and amplitude contrast are discussed. First, the SAWs phase delay gives a mainly linear dependence on the distance of the source. Second, the atomic oscillation trajectories within the SAW lead to a signal contribution that is made up of the shape of the oscillation trajectory and the local topography. On an atomic scale where the influence of the phase delay on the contrast can be neglected the oscillation trajectories of single surface atoms are studied. Finally, the atomically resolved phase and amplitude images are compared to simulated data.
{"title":"Surfing the SAW: visualizing the oscillation of Au(111) surface atoms","authors":"T. Hesjedal, E. Chilla, H.-J. Frohlich","doi":"10.1109/ULTSYM.1997.663073","DOIUrl":"https://doi.org/10.1109/ULTSYM.1997.663073","url":null,"abstract":"In this paper we report the observation of surface acoustic waves using a scanning tunneling microscope (STM). As the STM control electronics have a bandwidth limit in the kHz range, SAWs at typical frequencies of MHz to GHz cause a loss of contrast which can be clearly seen on an atomic scale. In order to access the amplitude and phase of a SAW, we introduced a heterodyning type STM, the scanning acoustic tunneling microscope (SATM). Contrary to the STM technique, the SATM measures snapshots of the state of oscillation. On the nanometer scale, two contributions to the phase and amplitude contrast are discussed. First, the SAWs phase delay gives a mainly linear dependence on the distance of the source. Second, the atomic oscillation trajectories within the SAW lead to a signal contribution that is made up of the shape of the oscillation trajectory and the local topography. On an atomic scale where the influence of the phase delay on the contrast can be neglected the oscillation trajectories of single surface atoms are studied. Finally, the atomically resolved phase and amplitude images are compared to simulated data.","PeriodicalId":6369,"journal":{"name":"1997 IEEE Ultrasonics Symposium Proceedings. An International Symposium (Cat. No.97CH36118)","volume":"33 1","pages":"511-514 vol.1"},"PeriodicalIF":0.0,"publicationDate":"1997-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78651031","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 : 1997-10-05DOI: 10.1109/ULTSYM.1997.661836
D. Boukerroui, O. Basset, A. Baskurt, A. Hernandez, N. Guérin, G. Giménez
A specific algorithm is presented for the automatic extraction of breast tumors. This algorithm involves 3D adaptive K-means clustering of the gray-scale and texture features images. The segmentation problem is formulated as a Maximum A Posterior (MAP) estimation problem. The MAP estimation is achieved using Besag's Iterated Conditional Modes algorithm for the minimization of an energy function. This function has three components. The first one constrains the region to be close to the data, the second imposes spatial continuity and the third takes into consideration the texture of the various regions. This segmentation technique is demonstrated on in vivo breast data. The method revealed very efficient. The results are compared with the manual segmentation of lesions by an expert.
{"title":"Texture based adaptive clustering algorithm for 3D breast lesion segmentation","authors":"D. Boukerroui, O. Basset, A. Baskurt, A. Hernandez, N. Guérin, G. Giménez","doi":"10.1109/ULTSYM.1997.661836","DOIUrl":"https://doi.org/10.1109/ULTSYM.1997.661836","url":null,"abstract":"A specific algorithm is presented for the automatic extraction of breast tumors. This algorithm involves 3D adaptive K-means clustering of the gray-scale and texture features images. The segmentation problem is formulated as a Maximum A Posterior (MAP) estimation problem. The MAP estimation is achieved using Besag's Iterated Conditional Modes algorithm for the minimization of an energy function. This function has three components. The first one constrains the region to be close to the data, the second imposes spatial continuity and the third takes into consideration the texture of the various regions. This segmentation technique is demonstrated on in vivo breast data. The method revealed very efficient. The results are compared with the manual segmentation of lesions by an expert.","PeriodicalId":6369,"journal":{"name":"1997 IEEE Ultrasonics Symposium Proceedings. An International Symposium (Cat. No.97CH36118)","volume":"42 1","pages":"1389-1392 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1997-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77676585","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 : 1997-10-05DOI: 10.1109/ULTSYM.1997.661806
C. Lim, J. Remeniéras, A. Roncin, M. Berson
Presents the performances of a new Doppler system using single channel RF sampling. The conventional quadrature method in Doppler imaging system has to use a minimum of two identical parallel demodulation channels to reconstruct the multigate analytic Doppler signal. However, this system suffers from hardware complexity and the problem of unbalance (gain and phase) between the channels. In order to reduce these problems, the authors realize a multigate pulsed Doppler system using undersampling on a single channel. It requires a sampling frequency at 4f/sub a/ and a 12 bits A/D converter. The proposed "Single-Channel RF Sampling" method aims to decrease the required sampling frequency proportionally to 4f/sub a//(2k+1). To show the influence of the factor k on the measurements, the authors compare the velocity profiles obtained in vitro and in vivo for different intersequence delay times (k=0 to 10). The authors have used a 4 MHz center frequency transducer. For experiments in vitro, on a phantom Doppler system, axial and volumetric velocity profiles in the vessel have been computed according to factor k and have been compared. The influence of the angle between the ultrasonic beam and the flow axis direction, and of the fluid viscosity on the velocity profiles obtained for different values of k factor is presented. For experiments in vivo on the carotid, the authors used a data acquisition system with a sampling frequency of 500 kHz and a dynamic range of 12 bits. The authors compare axial velocity profiles in systolic and diastolic phases obtained for different single channel RF sampling factors.
{"title":"Volumetric blood flow velocity measurement with multigate pulsed Doppler system using single-channel RF sampling","authors":"C. Lim, J. Remeniéras, A. Roncin, M. Berson","doi":"10.1109/ULTSYM.1997.661806","DOIUrl":"https://doi.org/10.1109/ULTSYM.1997.661806","url":null,"abstract":"Presents the performances of a new Doppler system using single channel RF sampling. The conventional quadrature method in Doppler imaging system has to use a minimum of two identical parallel demodulation channels to reconstruct the multigate analytic Doppler signal. However, this system suffers from hardware complexity and the problem of unbalance (gain and phase) between the channels. In order to reduce these problems, the authors realize a multigate pulsed Doppler system using undersampling on a single channel. It requires a sampling frequency at 4f/sub a/ and a 12 bits A/D converter. The proposed \"Single-Channel RF Sampling\" method aims to decrease the required sampling frequency proportionally to 4f/sub a//(2k+1). To show the influence of the factor k on the measurements, the authors compare the velocity profiles obtained in vitro and in vivo for different intersequence delay times (k=0 to 10). The authors have used a 4 MHz center frequency transducer. For experiments in vitro, on a phantom Doppler system, axial and volumetric velocity profiles in the vessel have been computed according to factor k and have been compared. The influence of the angle between the ultrasonic beam and the flow axis direction, and of the fluid viscosity on the velocity profiles obtained for different values of k factor is presented. For experiments in vivo on the carotid, the authors used a data acquisition system with a sampling frequency of 500 kHz and a dynamic range of 12 bits. The authors compare axial velocity profiles in systolic and diastolic phases obtained for different single channel RF sampling factors.","PeriodicalId":6369,"journal":{"name":"1997 IEEE Ultrasonics Symposium Proceedings. An International Symposium (Cat. No.97CH36118)","volume":"1 1","pages":"1255-1258 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1997-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79886860","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 : 1997-10-05DOI: 10.1109/ULTSYM.1997.661853
T. Taxt, J. Strand
This paper presents a new method for two-dimensional blind homomorphic deconvolution of medical B-scan ultrasound images. The method is based on noise robust two-dimensional phase unwrapping and a noise robust procedure to obtain the pulse in the complex cepstrum domain. Ordinary Wiener filtering is used in the subsequent deconvolution. The resulting images became much sharper, with better defined tissue structures compared to the ordinary images. The deconvolved images had a resolution gain in the order of 3 to 6, and the signal to noise ratio doubled for many of these images. The method gave stable results through several image sequences. It can be implemented in real time.
{"title":"Noise robust two-dimensional blind deconvolution of ultrasound images","authors":"T. Taxt, J. Strand","doi":"10.1109/ULTSYM.1997.661853","DOIUrl":"https://doi.org/10.1109/ULTSYM.1997.661853","url":null,"abstract":"This paper presents a new method for two-dimensional blind homomorphic deconvolution of medical B-scan ultrasound images. The method is based on noise robust two-dimensional phase unwrapping and a noise robust procedure to obtain the pulse in the complex cepstrum domain. Ordinary Wiener filtering is used in the subsequent deconvolution. The resulting images became much sharper, with better defined tissue structures compared to the ordinary images. The deconvolved images had a resolution gain in the order of 3 to 6, and the signal to noise ratio doubled for many of these images. The method gave stable results through several image sequences. It can be implemented in real time.","PeriodicalId":6369,"journal":{"name":"1997 IEEE Ultrasonics Symposium Proceedings. An International Symposium (Cat. No.97CH36118)","volume":"23 1","pages":"1465-1470 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1997-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88920964","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 : 1997-10-05DOI: 10.1109/ULTSYM.1997.661865
C. Sumi, K. Nakayama, M. Kubota
It is quite remarkable that the pathological state of living soft tissue highly correlates with quasi-static mechanical properties, i.e., particularly elasticity. With such a fact in mind, we previously developed "the iterative 2D rf-echo phase matching method" that determines the 2D displacement vector field generated in in vivo soft tissue during acquisition of two successive rf-echo data frames. That is, since this displacement measurement allows an accurate estimate of the resultant strain distributions to be obtained, we can stably quantify the tissue elasticity by determining the relative shear modulus distribution. Toward the finer elasticity imaging, we recently improved the previous displacement measurement method such that better phase matching can be realized. That is, we novelly incorporate an effective mechanism into the previous one: the local region size is made suitably smaller during the iterative phase matching. This leads to improvement of the quality of the finally obtained elasticity image. The effectiveness was verified through simulation, and an experiment on in vitro pork and in vivo breast tissues.
{"title":"Fine elasticity imaging utilizing the refined iterative rf-echo phase matching algorithm","authors":"C. Sumi, K. Nakayama, M. Kubota","doi":"10.1109/ULTSYM.1997.661865","DOIUrl":"https://doi.org/10.1109/ULTSYM.1997.661865","url":null,"abstract":"It is quite remarkable that the pathological state of living soft tissue highly correlates with quasi-static mechanical properties, i.e., particularly elasticity. With such a fact in mind, we previously developed \"the iterative 2D rf-echo phase matching method\" that determines the 2D displacement vector field generated in in vivo soft tissue during acquisition of two successive rf-echo data frames. That is, since this displacement measurement allows an accurate estimate of the resultant strain distributions to be obtained, we can stably quantify the tissue elasticity by determining the relative shear modulus distribution. Toward the finer elasticity imaging, we recently improved the previous displacement measurement method such that better phase matching can be realized. That is, we novelly incorporate an effective mechanism into the previous one: the local region size is made suitably smaller during the iterative phase matching. This leads to improvement of the quality of the finally obtained elasticity image. The effectiveness was verified through simulation, and an experiment on in vitro pork and in vivo breast tissues.","PeriodicalId":6369,"journal":{"name":"1997 IEEE Ultrasonics Symposium Proceedings. An International Symposium (Cat. No.97CH36118)","volume":"29 1","pages":"1521-1526 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1997-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90319391","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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