Publications
262 results found
Sennoga CA, Mahue V, Loughran J, et al., 2010, ON SIZING AND COUNTING OF MICROBUBBLES USING OPTICAL MICROSCOPY, ULTRASOUND IN MEDICINE AND BIOLOGY, Vol: 36, Pages: 2093-2096, ISSN: 0301-5629
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- Citations: 62
Li R, Song L, Elson DS, et al., 2010, Parallel detection of amplitude-modulated, ultrasound-modulated optical signals, OPTICS LETTERS, Vol: 35, Pages: 2633-2635, ISSN: 0146-9592
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- Citations: 10
Mari JM, Hibbs K, Stride E, et al., 2010, An approximate nonlinear model for Time Gain Compensation of Amplitude Modulated images of ultrasound contrast agent perfusion, IEEE Trans. UFFC, in press
Microbubble ultrasound contrast agents allow blood perfusion to be imaged at the cost of an increased attenuation that is not properly handled by existing Time Gain Compensation methods. An automatic TGC has been developed that is able to account for different microbubble concentrations. The technique is an extension of previously tested approach for modelling the nonlinear dependence of microbubble backscattering upon insonating pressure. The proposed method involves modelling in amplitude of the nonlinear attenuation for both forward and backward propagation, and the solution is achieved through an approximation set to overestimate the attenuation. The resulting equations are used to model and compensate Amplitude Modulation images; they are tested on radiofrequency data acquired using a clinical scanner from a gelatine tissue-mimicking phantom submerged in a contrast agent solution in the 0.08 MI – 0.51 MI range at 2 MHz. The nonlinear estimation equation presented here provides a significantly improved amplification profile compared to standard TGC algorithms, resulting in more accurate attenuation correction of the AM image.
Tang M-X, Kamiyama N, Eckersley RJ, 2010, EFFECTS OF NONLINEAR PROPAGATION IN ULTRASOUND CONTRAST AGENT IMAGING, ULTRASOUND IN MEDICINE AND BIOLOGY, Vol: 36, Pages: 459-466, ISSN: 0301-5629
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- Citations: 49
Mahue V, Mari JM, Eckersley RJ, et al., 2010, Pulse Subtraction Doppler, Internatilonnal Copngress of Ultrasonics
Tang M-X, Elson DS, Li R, et al., 2010, Photoacoustics, thermoacoustics, and acousto-optics for biomedical imaging, PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART H-JOURNAL OF ENGINEERING IN MEDICINE, Vol: 224, Pages: 291-306, ISSN: 0954-4119
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- Citations: 13
Sboros V, Tang M-X, 2010, The assessment of microvascular flow and tissue perfusion using ultrasound imaging, PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART H-JOURNAL OF ENGINEERING IN MEDICINE, Vol: 224, Pages: 273-290, ISSN: 0954-4119
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- Citations: 33
Poelma C, Mari JM, Foin N, et al., 2009, 3D flow reconstruction using ultrasound PIV, Experiments in Fluids, Vol: 50, Pages: 777-785, ISSN: 1432-1114
Ultrasound particle image velocimetry (PIV)can be used to obtain velocity fields in non-transparent geometries and/or fluids. In the current study, we use this technique to document the flow in a curved tube, usingultrasound contrast bubbles as flow tracer particles. The performance of the technique is first tested in a straight tube, with both steady laminar and pulsatile flows. Bothexperiments confirm that the technique is capable of reliable measurements. A number of adaptations are introduced that improve the accuracy and applicability of ultrasound PIV. Firstly, due to the method of ultrasoundimage acquisition, a correction is required for the estimation of velocities from tracer displacements. This correction accounts for the fact that columns in the image are recorded at slightly different instances. The second improvement uses a slice-by-slice scanning approach to obtain three-dimensional velocity data. This approach is here demonstrated in a strongly curved tube. The resultingflow profiles and wall shear stress distribution shows a distinct asymmetry. To meaningfully interpret these threedimensionalresults, knowledge of the measurement thickness is required. Our third contribution is a method to determine this quantity, using the correlation peak heights. The latter method can also provide the third (out-of-plane) component if the measurement thickness is known, so that all three velocity components are available using a single probe.
Stride E, Tang M-X, Eckersley RJ, 2009, Physical phenomena affecting quantitative imaging of ultrasound contrast agents, Special Session on Bubbles and Ultrasound held at the IOA 2008 Spring Conference, Publisher: ELSEVIER SCI LTD, Pages: 1352-1362, ISSN: 0003-682X
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- Citations: 49
Finfer DC, Tang MX, Eckersley RJ, 2009, Verification of an image calibration method in ultrasound contrast agent imaging on a perfusion phantom, Proceedings - IEEE Ultrasonics Symposium, Pages: 267-270, ISSN: 1051-0117
An image calibration method, based on "pulse inversion ratio" (PIR) was tested using a flow phantom consisting of a dialysis cartridge to simulate tissue perfusion. By comparing PIR to B-mode and PI output, it was seen that PIR is sensitive to the flow of contrast agents, and is capable of suppressing shadowing artifacts. ©2009 IEEE.
Mahue V, Mari JM, Eckersley RJ, et al., 2009, Comparison of pulse subtraction Doppler and pulse inversion Doppler, IEEE Ultrasonics Symposium
Hibbs K, Eckersley RJ, Noble A, et al., 2009, Ultrasound phase velocities in SonoVue™ as a function of pressure and bubble concentration, Proceedings - IEEE Ultrasonics Symposium, Pages: 1829-1832, ISSN: 1051-0117
This work investigates the effects of insonating pressure on ultrasound phase velocity in the SonoVue™ microbubble suspension. Ultrasound transmission measurements were carried out using a single element transducer and calibrated needle hydrophone, for a range of SonoVue™ concentrations from 50 to 800μl/l. Phase velocity was calculated using an established method based on the phase difference between pulses transmitted through the contrast agent and reference pulses for a range of insonating pressures from 13 to 128 kPa. Phase velocity was shown to be dependent on frequency, insonating pressure and SonoVue™ concentration. The relationship between pressure and phase velocity was found to be approximately linear, with the pressure-velocity gradient increasing with concentration. These results may have significant implications for contrast-enhanced ultrasonography, for example in understanding artifact generation and quantitative applications such as estimating local bubble concentration. ©2009 IEEE.
Li R, Elson DS, Dunsby C, et al., 2009, A study on optical modulation signal and tissue displacement in Ultrasound Modulated Optical Tomography, Conference on Photons Plus Ultrasound - Imaging and Sensing 2009, Publisher: SPIE-INT SOC OPTICAL ENGINEERING, ISSN: 0277-786X
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- Citations: 1
Stride E, Tang M, Eckersley R, 2008, Modelling ultrasound contrast agents: Current challenges, Pages: 408-415, ISSN: 1478-6095
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- Citations: 1
Tang MX, Eckersley RJ, Stride E, 2008, Quantitative imaging of ultrasound contrast agents: Current challenges, Pages: 416-423, ISSN: 1478-6095
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- Citations: 1
Eckersley RJ, Chetty K, Stride E, et al., 2008, Microbubble contrast agents for medical ultrasound imaging: Current issues and new directions, Proceedings of the Institute of Acoustics, Vol: 30, Pages: 402-407, ISSN: 1478-6095
Microbubbles have shown great promise for enhancing medical ultrasound imaging, with both potential and proven applications in Radiology and Cardiology and many other clinical areas. More recently the use of targeted agents for molecular imaging is being studied and the use of microbubble as mediators for the delivery of drugs and gene therapy is being investigated. In this presentation the basis for these different uses of microbubbles will be described and the challenges which are limiting the widespread acceptance and implementation of these techniques, will be outlined. These include issues relating to image artefacts, image quantitation and the complexity of interactions between microbubbles and both the ultrasound field and the human body.
Tang M-X, Mari J-M, Wells PNT, et al., 2008, ATTENUATION CORRECTION IN ULTRASOUND CONTRAST AGENT IMAGING: ELEMENTARY THEORY AND PRELIMINARY EXPERIMENTAL EVALUATION, ULTRASOUND IN MEDICINE AND BIOLOGY, Vol: 34, Pages: 1998-2008, ISSN: 0301-5629
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- Citations: 29
Yeh JSM, Sennoga C, Mcconnell E, et al., 2008, Molecular imaging of the heart using contrast ultrasound: acoustic quantification of molecular expressions, EUROPEAN HEART JOURNAL, Vol: 29, Pages: 21-21, ISSN: 0195-668X
Yeh JSM, Sennoga C, McConnell E, et al., 2008, Echo identification and quantification of inflammatory molecules in the heart, Annual Scientific Conference of the British-Cardiovascular-Society/British-Society-for-Cardiovascular-Research, Publisher: B M J PUBLISHING GROUP, Pages: A21-A22, ISSN: 1355-6037
Tang MX, Eckersley R, 2008, Nonlinear propagation in microbubble cloud, does it make the distal myocardium appear brighter or darker., J Acoust Soc Am, Vol: 123, Pages: 3113-3113, ISSN: 1520-8524
A number of questions remain in contrast ultrasound imaging regarding the complex interaction between bubbles, US and tissue. E.g. in contrast echocardiography for perfusion imaging, it is sometimes difficult to interpret the images for the myocardium distal to the probe. Due to US nonlinear propagation through the bubble-filled chamber, the distal part can appear artefactually brighter or darker in e.g. Pulse Inversion images. Although tissue at target is likely to increase in brightness in contrast specific images when nonlinear propagation happens, it is less clear for microbubbles. This work tries to gain better understanding of this by investigating how nonlinear propagation of ultrasound pulses can change the appearance of microbubbles and tissues in Pulse Inversion images by altering their acoustic response. A series of specifically designed simulations and experiments were performed. The results show that nonlinear propagation can have a significant impact on the appearance of tissue containing bubbles, and this varies with insonating frequency and pressure. These results suggest the mechanism involves a balance between a reduction in nonlinear bubble scattering after propagation against an increase in the nonlinear tissue scattering. Consequently the deeper tissues containing bubbles may appear brighter or darker depending on the relative contribution of these two effects.
Tang M-X, Mari J-M, Wells PNT, et al., 2008, Automatic attenuation correction in ultrasound contrast agent imaging, 13th European symposium on ultrasound contrast imaging
Mari JM, Hibbs K, Tang MX, 2007, A non-linear ultrasonic scattering approach for micro bubble concentration quantification, Pages: 2183-2186, ISSN: 0589-1019
Ultrasonic imaging of microbubble contrast agents and their concentration quantification is an ongoing problem, complicated by the lack of accurate attenuation compensation (TGC) algorithms and by the complex behaviour of microbubbles. Indeed the ultrasound contrast agents behave non linearly in the power range for medical imaging, while the biological tissues behave mainly linearly. Such quantification is required to allow the physicians to estimate the local blood perfusion in the biological tissues. But the different imaging methods developed to distinguish the agent from the surrounding tissues do not give an accurate representation of local agent concentration, which therefore has to be qualitatively estimated by the physicians. In this paper, we expand an existing automatic attenuation compensation algorithm by introducing a nonlinear relationship between insonating power and scattering when medium acoustic pressure is used (0.33 MI - 0.52 MI at 3MHz), and model amplitude modulation (AM). An acquisition system is set up to allow acquisitions of radio frequency data from Sonovue® suspension with a programmable ultrasound scanner and a sectorial probe. Results show that the behaviour of microbubble clouds with pressure and concentration follow the evolution expected from the assumptions formulated to be able to develop the model. In particular, the proposed equations for concentration estimation correctly predict the true concentration in the range [0-228] μL/L. © 2007 IEEE.
J-M Mari, K Hibbs, M-X Tang, 2007, A non-linear ultrasonic scattering approach for micro bubble concentration quantification, 29th Annual International Conference of the IEEE EMBS Society
M-X Tang, RJ Eckersley, 2007, Beam Hardening in Ultrasound Contrast Agent Imaging, proceedings of the International Congress on Ultrasonic
RJ Eckersley, M-X Tang, 2007, Microbubble contrast agent detection using pulse encoded sequences, the 12th European Symposium on Ultrasound Contrast Imaging
Hibbs K, Mari JM, Stride E, et al., 2007, Nonlinear propagation of ultrasound through microbubble clouds: A novel numerical implementation, IEEE Ultrasonics Symposium, Publisher: IEEE, Pages: 1997-+, ISSN: 1051-0117
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- Citations: 4
Tang M, Eckersley R J, 2007, Frequency and pressure dependent attenuation and scattering by microbubbles, Ultrasound in Medicine and Biology, Vol: 33, Pages: 164-168, ISSN: 0301-5629
Sze G, Wang W, Qiao G, et al., 2007, Preliminary investigation of correlation between in-vitro specimen measurement and in-vivo imaging data from ROI analysis, 13th International Conference on Electrical Bioimpedance/8th Conference on Electrical Impedance Tomography, Publisher: SPRINGER, Pages: 440-+, ISSN: 1680-0737
Eckersley RJ, Tang M-X, 2007, Microbubble contrast agent detection using binary coded pulses, ULTRASOUND IN MEDICINE AND BIOLOGY, Vol: 33, Pages: 1787-1795
M-X Tang, RJ Eckersley, 2006, Nonlinear corruption of ultrasound transmission by microbubble contrast agents, the 11th European Symposium on Ultrasound Contrast Imaging
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