2010 IEEE International Ultrasonics Symposium最新文献

{"title":"Aberration correction using moving particles speckle noise for ultrafast ultrasonic imaging","authors":"B. Osmanski, G. Montaldo, M. Tanter","doi":"10.1109/ULTSYM.2010.5935904","DOIUrl":"https://doi.org/10.1109/ULTSYM.2010.5935904","url":null,"abstract":"The correction of sound speed heterogeneities is an important problem in trans-skull and deep organs imaging. Among all the proposed adaptive focusing methods, time reversal is an elegant one that enables to know the Green's function between the ultrasonic array and a punctual scatterer. However, in the absence of strong well resolved scatterers, time reversal is not useful. In this work we propose to use the echoes coming from moving particles in a flow to generate a virtual point-like scatterer and focus on it by iterative time reversal. This method enables to focus adaptively anywhere a flow is present. Then we use the Green's function to correct the ultrasound images. First, we apply this technique using focused wave then to improve it, we use the ultrafast plane wave imaging and synthetic focusing","PeriodicalId":6437,"journal":{"name":"2010 IEEE International Ultrasonics Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2010-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87441810","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Theoretical and experimental investigation of langasite as material for wireless high temperature SAW sensors","authors":"S. Sakharov, S. Kondratiev, A. Zabelin, N. Naumenko, A. Azarov, S. Zhgoon, A. Shvetsov","doi":"10.1109/ULTSYM.2010.5935533","DOIUrl":"https://doi.org/10.1109/ULTSYM.2010.5935533","url":null,"abstract":"Different cuts of langasite were investigated theoretically and experimentally as candidates for high temperature sensors utilizing SAW resonators and reflecting SAW tags. Single port SAW resonators with central frequencies close to 170, 200 and 433 MHz with W, Ir and Pt electrodes of different thickness were fabricated and their characteristics were measured as functions of temperature. An approach to SAW device encapsulation, which helps to avoid stress development during heating to high temperatures, was suggested and tested. The damage of the langasite surface during heating to high temperature is strong in the cut family with Euler angles (0°, 138.5°, ψ), while orientations with Euler angles (0°, 90°, ψ) and (0°, 22°, ψ) were found to be more resistant to heating. In the latter cut family, two cuts, (0°, 22°, 31.5°) and (0°, 22°, 90°) can provide zero power flow angle and sufficient piezoelectric coupling. COM parameters of SAW resonators with W, Ir and Pt electrodes, including complex reflection coefficient, were calculated as functions of electrode thickness and measured in the wide temperature range. The frequency responses were described by COM equations and the fitted COM-parameters were compared to their simulated values. Resonators show high Q and their performance is perfectly described by COM equations","PeriodicalId":6437,"journal":{"name":"2010 IEEE International Ultrasonics Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2010-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90597069","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Can therapeutic ultrasound be used as a reversible male contraceptive?","authors":"J. Tsuruta, P. Dayton, R. Gessner, T. S. Gregory, Michael A. Streicker, Glenda Moser, Erick J. R. Silva, D. Sokal","doi":"10.1109/ULTSYM.2010.5935958","DOIUrl":"https://doi.org/10.1109/ULTSYM.2010.5935958","url":null,"abstract":"Background, Motivation and Objective: Studies on the utility of ultrasound as a reversible male contraceptive were initially reported in the 1970s by Fahim and his colleagues. Their studies with rat and human subjects showed that a single dose of ultrasound could dramatically decrease sperm count and induced infertility for up to six months. Depending upon the dose of ultrasound, this contraceptive effect was reversible. Our objective was to determine if modern therapeutic ultrasound instruments could form the basis for a male contraceptive, and to elucidate acoustic mechanism of observed infertility. Statement of Contribution/Methods: In order to determine effect of ultrasound on reproductive capacity in-vivo, rat testes were subjected to 2.2 W/cm2 ultrasound at either 1 or 3 MHz using a therapeutic ultrasound generator and transducer. Testis histology and sperm counts were examined two weeks after treatment. To elucidate mechanism of ultrasound effects on reproductive cells, sperm from rat epididymis were sonicated in-vitro in a dual optical-acoustic-focus setup with 1 MHz pulses with lengths ranging from 1,000 to 10,000 cycles. Pulses had peak negative pressures between ∼1 and 10 MPa and were delivered at a 1 Hz PRF for between 30 and 90 s. Results: Sham-treated rats produced sperm counts between 200 to 300 million sperm per cauda epididymis, while ultrasound treatment reduced sperm counts to ∼2 million sperm per cauda epididymis two weeks after treatment. Sperm recovered from ultrasound-treated rats had reduced motility. The corpus and caput epididymis of treated animals had significantly lower numbers of sperm than sham-treated animals. In addition, portions of the epididymis had decreased tubular diameters, similar to that seen in castrated animals. The height of the seminiferous epithelium in ultrasound-treated rats decreased significantly compared to sham-treated animals, due to a significant loss of testicular germ cells. Individual sperm exposed to ultrasound ex-vivo were observed to be extremely resistant to acoustic energy. In-vitro sonication of sperm up to ∼ 10 Megapascals at 1 MHz did not permanently alter their motility after pulses were delivered. However, if microbubbles were present in the solution, cavitation caused permanent and terminal disruption of the cells within the field of view. Discussion and Conclusions: Our studies using modern therapeutic ultrasound instrumentation demonstrate the feasibility of using ultrasound as a form of male contraception. However, in-vitro studies have not yet elucidated the mechanism of cell disruption. Further studies determining the kinetics of germ cell loss, direct effects on sperm, the duration of the contraceptive effect, and any long-term effects to the seminiferous, interstitial or epididymal epithelia are needed to establish the efficacy and reversibility of any ultrasound-based contraceptive.","PeriodicalId":6437,"journal":{"name":"2010 IEEE International Ultrasonics Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2010-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80680173","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Adaptive focusing of transcranial therapeutic ultrasound using MR Acoustic Radiation Force Imaging in a clinical environment","authors":"L. Marsac, B. Larrat, M. Pernot, B. Robert, M. Fink, J. Aubry, M. Tanter","doi":"10.1109/ULTSYM.2010.5935959","DOIUrl":"https://doi.org/10.1109/ULTSYM.2010.5935959","url":null,"abstract":"Background: In order to focus ultrasound beams through aberrating layers such as fat or bones, adaptive focusing techniques have been proposed to improve the focusing, mostly based on the backscattered echoes. We recently proposed an energy-based technique with the sole requirement being knowledge of the acoustic intensity at the desired focus. Here, Magnetic Resonance-Acoustic Radiation Force Imaging (MR-ARFI) is used to map the displacement induced by the radiation force of a focused ultrasound beam. As the maximum displacement is obtained with the best corrected beam, such a measurement can lead to aberration correction. Material and methods: Proof of concept experiments were previously shown in a small animal MR at 7 T using a 64-elements linear phased array operating at 6 MHz. Optimal refocusing was then obtained through numerical and physical aberrating layers. This work is extended here in a clinical Philips 1.5 T Achieva scanner. The HIFU beam is generated using a 512 elements US phased array (SuperSonic Imagine, France) dedicated to transcranial human experiments and operating at 1 MHz. Experiments are conducted in phantom gels and ex vivo brain tissues through numerical phase aberrators. A motion-sensitized spin echo sequence (TE = 70 ms, TR = 1200 ms, spatial resolution is 2×2×7 mm3) is implemented to measure displacements induced by the acoustic radiation force of transmitted beams. Results: MR-ARFI allowed mapping the distribution of the radiation force at the focus of the array. After the recording of the MR phase signals for different US emissions, the proposed adaptive focusing technique was able to recover the spatial distribution of the phase aberrations. Total acquisition time for 384 ultrasonic emission channels was 2 hours. Conclusion: Those first results in clinical MR at 1.5 T show that adaptive focusing of a human transcranial brain HIFU system can be achieved within reasonable time under MR guidance for aberrator layers as strong as human skull. Ongoing work is aiming at accelerating the acquisition in order to reach acceptable durations for in vivo protocols.","PeriodicalId":6437,"journal":{"name":"2010 IEEE International Ultrasonics Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2010-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91238489","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Measurements from 22 to 105 MHz of the apparent anisotropy of ultrasonic backscatter from coronary arteries with atherosclerotic plaques identified by intravascular ultrasound","authors":"J. J. Hoffman, Benjamin L. Johnson, M. Holland, R. Fedewa, A. Nair, James G. Miller","doi":"10.1109/ULTSYM.2010.5935625","DOIUrl":"https://doi.org/10.1109/ULTSYM.2010.5935625","url":null,"abstract":"It is speculated that the anisotropic structure of coronary arteries may cause images of the coronary arteries produced by future oblique and forward-looking IVUS catheters to appear significantly different than the images produced by current side-looking IVUS catheters. In anticipation of these systems and to understand better the fundamental properties of the coronary arteries and associated plaques, we compare the measured anisotropy of ultrasonic backscatter in coronary arteries between side-looking and forward-looking directions over the bandwidth from 22 to 105 MHz. To do so, 44 segments from 19 human coronary arteries were each measured ultrasonically in 8 configurations. Each segment was imaged first with two clinical IVUS systems, and subsequently in two orthogonal orientations by an acoustic microscope operating with 3 interchangeable transducers of nominal center frequencies of 25, 50, and 100 MHz. The backscatter trend observed with side-looking IVUS was consistent with radial acoustic microscopy results, but axial acoustic microscopy exhibited a reversal of the typical pattern, with the media demonstrating greater apparent integrated backscatter than the intima/plaque. These results suggest that future IVUS catheters operating in new imaging planes may need to account for tissue anisotropy, and may be able to exploit this anisotropy for diagnostic advantage.","PeriodicalId":6437,"journal":{"name":"2010 IEEE International Ultrasonics Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2010-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89468199","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"CMUT-on-CMOS for forward-looking IVUS: Improved fabrication and real-time imaging","authors":"M. Hochman, J. Zahorian, S. Satir, G. Gurun, T. Xu, M. Karaman, P. Hasler, F. Degertekin","doi":"10.1109/ULTSYM.2010.5935979","DOIUrl":"https://doi.org/10.1109/ULTSYM.2010.5935979","url":null,"abstract":"The capability to monolithically integrate CMUTs with underlying front-end electronics is promising for forward-looking (FL) imaging catheters with improved SNR and smaller size. We previously demonstrated feasibility of CMUT-on-CMOS arrays for FL imaging and obtained pulse-echo results from individual elements. Here we describe recent improvements in the fabrication process and initial results from a test setup capable of real-time image data collection using CMUT-on-CMOS arrays. Dual-ring CMUT arrays were fabricated on silicon wafers with 0.35 µm CMOS front-end electronics processed at a commercial foundry. The critical changes made in the fabrication process involved in-house polishing followed by a chemical stripping of the aluminum oxide slurry. We also added 0.2 µm of silicon nitride before CMUT to CMOS interconnect via etching. We made these modifications to improve surface quality, alleviating wirebonding stiction issues. The real-time imaging test setup uses an FPGA to control Tx/Rx element selection and data collection functions. The Tx electronics are capable of generating high voltage, broadband, bipolar pulses up to 100V in amplitude. The 4 Rx channels coming out of the CMUT-on-CMOS chip are simultaneously digitized using a 14 bit 250 MS/s digitizer. 12 MHz dual-ring CMUT-on-CMOS arrays were used for real-time imaging of various targets. The results show that these arrays, coupled with an FPGA controlled data acquisition system, can produce true volumetric images in front of the array in real time.","PeriodicalId":6437,"journal":{"name":"2010 IEEE International Ultrasonics Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2010-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89548601","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"In-vivo and in-vitro verification of optimal transmit phasing for harmonic background suppression with bipolar square wave pulser","authors":"C. Shen, Yun Yang","doi":"10.1109/ULTSYM.2010.5935615","DOIUrl":"https://doi.org/10.1109/ULTSYM.2010.5935615","url":null,"abstract":"Ultrasonic harmonic imaging has been routinely used to improve the detection of contrast microbubbles, but the contrast-to-tissue ratio (CTR) is generally limited by tissue harmonics and leakage harmonics in the tissue background. We have previously proposed the method of optimal transmit phasing to increase the CTR by relatively phasing these two harmonic components to cancel out each other for tissue background suppression. Nevertheless, since most clinical systems are only equipped with bipolar square wave pulser, effective procedures for binary conversion of continuous transmit signal become essential to generate arbitrarily phased bipolar waveforms. In this study, the sigma-delta modulation is combined with code tuning to achieve this goal. Our results indicate that, though the harmonic magnitude becomes abrupt with the transmit phasing when the bipolar waveform is utilized in optimal transmit phasing, effective harmonic suppression is still achievable in the tissue background. For in-vivo imaging, the bipolar transmit waveform with the optimal suppression phase improves the CTR by about 5 dB. It should be noted that, however, the abrupt harmonic magnitude with transmit phasing could pose difficulties in the selection of the optimal suppression phase and thus limit the clinical applicability of optimal transmit phasing.","PeriodicalId":6437,"journal":{"name":"2010 IEEE International Ultrasonics Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2010-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89764126","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Performance evaluation of nonlinear frequency modulated signals in ultrasound harmonic imaging","authors":"M. Arif, S. Harput, S. Freear","doi":"10.1109/ULTSYM.2010.5935665","DOIUrl":"https://doi.org/10.1109/ULTSYM.2010.5935665","url":null,"abstract":"In ultrasound harmonic imaging with linear frequency modulated (LFM) excitation, the sidelobes level in the compressed harmonic signal can be reduced by applying a windowing function. Windowing on the transmitting signal causes reduced penetration depth, whilst windowing on the receiving side results in reduced signal-to-noise ratio (SNR) gain and axial resolution. To optimize the transmitting signal energy and the SNR gain with reduced sidelobes level in the compressed harmonic signal, the use of nonlinear frequency modulated (NLFM) signals are proposed. The NLFM signal and associated second harmonic matched filter are designed using an analytical approach to minimise correlation errors. In all simulations and experiments, the NLFM signal performance is compared with the reference LFM signal of similar sweeping bandwidth and duration. The results indicate at least a 15 dB reduction in the peak sidelobes level of the NFLM compressed second harmonic signal with comparable axial mainlobe width when compared with the LFM compressed harmonic signal.","PeriodicalId":6437,"journal":{"name":"2010 IEEE International Ultrasonics Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2010-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90200725","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Study of the effect of beam spreading on systematic Doppler flow measurement errors","authors":"D. V. Mahadeva, S. Huang, G. Oddie, R. Baker","doi":"10.1109/ULTSYM.2010.5935748","DOIUrl":"https://doi.org/10.1109/ULTSYM.2010.5935748","url":null,"abstract":"Doppler ultrasonic flowmeters are based on a single ray approximation. We have studied the effect of beam spreading on the systematic Doppler flow measurement by developing a theoretical ray tracing model and validating the same with experiments. This paper will discuss experimental work and the use of ray tracing and finite element models to investigate this effect. This paper indicates some early trends which we have identified, but should be treated as \"work in progress\".","PeriodicalId":6437,"journal":{"name":"2010 IEEE International Ultrasonics Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2010-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76585175","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dual-frequency excitation enhances targeted delivery of ultrasound microbubbles","authors":"Ting-Yu Huang, C. Yeh","doi":"10.1109/ULTSYM.2010.5935878","DOIUrl":"https://doi.org/10.1109/ULTSYM.2010.5935878","url":null,"abstract":"Ultrasound radiation force (USRF) is commonly used to facilitate the efficiency of targeted bubble adhesion. Studying the property of adherent bubbles provides opportunities for the further control of targeted drug delivery and release. Previous reports show that USRF provides better targeting efficiency as USRF transmitting frequency close to bubbles' resonance frequency. However, low-frequency ultrasound suffers from a large sample volume such that USRF cannot be pinpointed to a specified region of interest. In this study, we proposed a high-frequency dual-frequency (DF) excitation with a low-frequency envelope component close to bubbles' resonance frequency to enhance the bubbles targeting efficiency while retaining a high spatial resolution. The results show that dual-frequency excitation with envelope frequency of 20 MHz (DF-20) and 30 MHz (DF-30) nearing the resonance frequency of submicron bubbles provided targeting enhancement up to 4.6–6.2 folds within 2 minutes. In comparisons to DF-3 and DF-10 excitations, which corresponding envelope frequencies were far from the resonance frequency of submicron bubbles, perform only 2.7–3.3 folds enhancement within 5 minutes.","PeriodicalId":6437,"journal":{"name":"2010 IEEE International Ultrasonics Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2010-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76631453","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}