Mr. Matthias Bo Stuart Profile

Matthias Bo Stuart

at Technical University of Denmark

SPIE Involvement:

Author

Publications (14)

Proceedings Article | 4 April 2022 Presentation + Paper

Fast super resolution ultrasound imaging using the erythrocytes

Jørgen Arendt Jensen, Mikkel Schou, Sofie Bech Andersen, Stinne Byrholdt Søgaard, Charlotte Mehlin Sørensen, Michael Bachmann Nielsen, Carsten Gundlach, Hans Martin Kjer, Anders Bjorholm Dahl, Matthias Bo Stuart, Borislav Gueorguiev Tomov

Proceedings Volume 12038, 120380E (2022) https://doi.org/10.1117/12.2612245

KEYWORDS: Ultrasonography, Image resolution, Kidney, Super resolution, Tissues, Data acquisition, Scanners, Visualization, Point spread functions, Heart

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Proceedings Article | 4 April 2022 Presentation + Paper

Fast super resolution ultrasound imaging by tracking of erythrocytes using different velocity constraints

Mostafa Amin-Naji, Iman Taghavi, Stinne Byrholdt Søgaard, Sofie Bech Andersen, Charlotte Mehlin Sørensen, Matthias Bo Stuart, Jørgen Arendt Jensen

Proceedings Volume 12038, 120380G (2022) https://doi.org/10.1117/12.2612355

KEYWORDS: Ultrasonography, Super resolution, Image fusion, Discrete wavelet transforms, Visualization, Target acquisition, Data acquisition, Particles, Image enhancement, Medical imaging, Biomedical ultrasonography, Ultrasound real time imaging, Ultrasonics, Medical image processing

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Proceedings Article | 4 April 2022 Presentation + Paper

Microbubble tracking with a forward-backward strategy

Iman Taghavi, Sofie Bech Andersen, Mikkel Schou, Michael Bachmann Nielsen, Charlotte Mehlin Sørensen, Matthias Bo Stuart, Jørgen Arendt Jensen

Proceedings Volume 12038, 120380C (2022) https://doi.org/10.1117/12.2610753

KEYWORDS: Ultrasonography, Kidney, Filtering (signal processing), In vivo imaging, Visualization, Super resolution, Super resolution microscopy, Detection and tracking algorithms

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Proceedings Article | 15 March 2019 Presentation + Paper

Row-column beamforming with dynamic apodizations on a GPU

Matthias Bo Stuart, Mikkel Schou, Jørgen Arendt Jensen

Proceedings Volume 10955, 109550Q (2019) https://doi.org/10.1117/12.2512418

KEYWORDS: Apodization, Phased arrays, Point spread functions, MATLAB, Computer programming, Imaging systems, Ultrasonography, 3D image processing, Image quality, Transducers

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Proceedings Article | 1 April 2016 Paper

Optimization of synthetic aperture image quality

Ramin Moshavegh, Jonas Jensen, Carlos Villagomez-Hoyos, Matthias Stuart, Martin Christian Hemmsen, Jørgen Arendt Jensen

Proceedings Volume 9790, 97900Z (2016) https://doi.org/10.1117/12.2216506

KEYWORDS: Image quality, Image resolution, Objectives, Ultrasonography, Synthetic aperture radar, Image analysis, Synthetic aperture imaging, Ultrafast imaging, Transducers, Point spread functions, Computer simulations, Apodization

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Proceedings Article | 1 April 2016 Paper

3D vector flow using a row-column addressed CMUT array

Simon Holbek, Thomas Lehrmann Christiansen, Mathias Engholm, Anders Lei, Mathias Bo Stuart, Christopher Beers, Lars Nordahl Moesner, Jan Peter Bagge, Erik Vilain Thomsen, Jørgen Arendt Jensen

Proceedings Volume 9790, 979005 (2016) https://doi.org/10.1117/12.2216721

KEYWORDS: Ultrasonography, Ultrasonics, Transducers, 3D image processing, Electrodes, Prototyping, Apodization, Blood, Scanners, Motion estimation

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Proceedings Article | 1 April 2016 Paper

High frame rate synthetic aperture vector flow imaging for transthoracic echocardiography

Carlos Villagómez-Hoyos, Matthias Stuart, Thor Bechsgaard, Michael Bachmann Nielsen, Jørgen Arendt Jensen

Proceedings Volume 9790, 979004 (2016) https://doi.org/10.1117/12.2216707

KEYWORDS: Ultrasonography, Cardiac imaging, Echocardiography, Heart, Tissues, In vivo imaging, Blood circulation, Blood, Scanners, Diagnostics, Transducers, Point spread functions, Synthetic aperture radar

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Proceedings Article | 1 April 2016 Paper

Volumetric synthetic aperture imaging with a piezoelectric 2D row-column probe

Hamed Bouzari, Mathias Engholm, Thomas Lehrmann Christiansen, Christopher Beers, Anders Lei, Matthias Bo Stuart, Svetoslav Ivanov Nikolov, Erik Vilain Thomsen, Jørgen Arendt Jensen

Proceedings Volume 9790, 97900Y (2016) https://doi.org/10.1117/12.2216074

KEYWORDS: Point spread functions, Transducers, Ultrasonography, Signal to noise ratio, Synthetic aperture imaging, 3D image processing, Spatial resolution, Prototyping, Scanners, Tissues, Apodization, Electrodes

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Proceedings Article | 17 March 2015 Paper

In vivo real-time volumetric synthetic aperture ultrasound imaging

Hamed Bouzari, Morten Rasmussen, Andreas Brandt, Matthias Stuart, Svetoslav Nikolov, Jørgen Jensen

Proceedings Volume 9419, 94190I (2015) https://doi.org/10.1117/12.2081631

KEYWORDS: Ultrasonography, In vivo imaging, Transducers, Synthetic aperture radar, Scanners, Imaging systems, Tissues, Acoustics, Temporal resolution, Signal to noise ratio

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Proceedings Article | 20 March 2014 Paper

Simulation study of real time 3D synthetic aperture sequential beamforming for ultrasound imaging

Martin Christian Hemmsen, Morten Fischer Rasmussen, Matthias Bo Stuart, Jørgen Arendt Jensen

Proceedings Volume 9040, 90401K (2014) https://doi.org/10.1117/12.2044017

KEYWORDS: Transducers, Phased arrays, Apodization, Ultrasonography, 3D image processing, Optical simulations, Computer simulations, Image resolution, Imaging systems, Image quality

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Proceedings Article | 20 March 2014 Paper

Rapid measurements of intensities for safety assessment of advanced imaging sequences

Jørgen Arendt Jensen, Morten Fischer Rasmussen, Matthias Bo Stuart, Borislav Tomov

Proceedings Volume 9040, 90400Z (2014) https://doi.org/10.1117/12.2043688

KEYWORDS: Scanners, Transducers, Imaging systems, Calibration, Safety, Ultrasonography, Acoustics, Data storage, Multichannel imaging systems, Time metrology

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FDA requires that intensity and safety parameters are measured for all imaging schemes for clinical imaging. This is often cumbersome, since the scan sequence has to broken apart, measurements conducted for the individually emitted beams, and the final intensity levels calculated by combining the intensities from the individual beams. This paper suggests a fast measurement scheme using the multi-line sampling capability of modern scanners and research systems. The hydrophone is connected to one sampling channel in the research system, and the intensity is measured for all imaging lines in one emission sequence. This makes it possible to map out the pressure field and hence intensity level for all imaging lines in a single measurement. The approach has several advantages: the scanner does not have to be re-programmed and can use the scan sequence without modification. The measurements are orders of magnitude faster (minutes rather than hours) and the final intensity level calculation can be made generic and reused for any kind of scan sequence by just knowing the number of imaging lines and the pulse repetition time. The scheme has been implemented on the Acoustic Intensity Measurement System AIMS III (Onda, Sunnyvale, California, USA). The research scanner SARUS is used for the experiments, where one of the channels is used for the hydrophone signal. A 3 MHz BK 8820e (BK Medical, Herlev, Denmark) convex array with 192 elements is used along with an Onda HFL-0400 hydrophone connected to a AH-2010 pre-amplifier (Onda Corporation, Sunnyvale, USA). A single emission sequence is employed for testing and calibrating the approach. The measurements using the AIMS III and SARUS systems after calibration agree within a relative standard deviation of 0.24%. A duplex B-mode and flow sequence is also investigated. The complex intensity map is measured and the time averaged spatial peak intensity is found. A single point measurement takes 3.43 seconds and the whole sequence can be characterized on the acoustical axis in around 6 minutes.

Proceedings Article | 20 March 2014 Paper

Increasing the dynamic range of synthetic aperture vector flow imaging

Carlos Villagomez Hoyos, Matthias Bo Stuart, Jørgen Arendt Jensen

Proceedings Volume 9040, 904011 (2014) https://doi.org/10.1117/12.2043637

KEYWORDS: Transducers, Ultrasonography, Adaptive optics, Blood, Data acquisition, Scanners, Blood circulation, Beam analyzers, Apodization, Neon

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In current ultrasound systems the dynamic range of detectable velocities is susceptible to the selected pulse repetition frequency, thus limiting the dynamic range of flow mapping. To establish the feasibility of extending the range of detectable velocities towards low velocity vessels, results are presented using synthetic aperture which increases the frame-to-frame signal correlation of the scatterer displacement while providing continuous data. In this paper, recursive synthetic aperture acquisition, directional beamforming, and cross-correlation are used to produce B-mode and vector velocity images. The emissions for the two imaging modes are interleaved 1-to-1 ratio, providing a high frame rate equal to the effective pulse repetition frequency of each imaging mode. The direction of the flow is estimated, and the velocity is then determined in that direction. This method works for all angles, including fully axial and transverse flows. The method is investigated using Field II simulations and data from the experimental ultrasound scanner SARUS, acquired from a circulating flow rig with a parabolic flow. A 7 MHz linear array transducer is used, and several pulse repetition frequencies are synthesized in a simulated flow phantom with linearly increasing velocity and in a dual-vessel phantom with laminar flow with peak velocities of 0.05 m/s and 0.5 m/s. The experimental measurements are made with laminar flow as in the simulations. For the simulated and experimental vessel with peak velocity of 0.05 m/s and flow angle of 75°, the relative bias is -0.29% and -3.19%, and the relative standard deviations are 2.39% and 5.75% respectively. For the simulated and experimental vessel with peak velocity of 0.5 m/s and flow angle of -90°, the relative biases are -4.30% and -7.37%, and the relative standard deviations are 1.59% and 6.12%, respectively. The presented method can improve the estimates by synthesizing a lower pulse repetition frequency, thereby increasing the dynamic range of the vector velocity imaging.

Proceedings Article | 29 March 2013 Paper

Preliminary examples of 3D vector flow imaging

Michael Pihl, Matthias Stuart, Borislav Tomov, Jens Hansen, Morten Rasmussen, Jørgen Jensen

Proceedings Volume 8675, 86750H (2013) https://doi.org/10.1117/12.2006845

KEYWORDS: 3D image processing, 3D acquisition, Data acquisition, Visualization, 3D metrology, Ultrasonography, Transducers, Magnetic resonance imaging, Stereoscopy, Motion measurement

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This paper presents 3D vector flow images obtained using the 3D Transverse Oscillation (TO) method. The method employs a 2D transducer and estimates the three velocity components simultaneously, which is important for visualizing complex flow patterns. Data are acquired using the experimental ultrasound scanner SARUS on a flow-rig system with steady flow. The vessel of the flow-rig is centered at a depth of 30 mm, and the flow has an expected 2D circular-symmetric parabolic profile with a peak velocity of 1 m/s. Ten frames of 3D vector flow images are acquired in a cross-sectional plane orthogonal to the center axis of the vessel, which coincides with the y-axis and the flow direction. Hence, only out-of-plane motion is expected. This motion cannot be measured by typical commercial scanners employing 1D arrays. Each frame consists of 16 flow lines steered from -15 to 15 degrees in steps of 2 degrees in the ZX-plane. For the center line, 3200 M-mode lines are acquired yielding 100 velocity profiles. At the center of the vessel, the mean and standard deviation of the estimated velocity vectors are (v_x, v_y, v_z) = (-0.026, 95, 1.0)±(8.8, 6.2, 0.84) cm/s compared to the expected (0.0, 96, 0.0) cm/s. Relative to the velocity magnitude this yields standard deviations of (9.1, 6.4, 0.88) %, respectively. Volumetric flow rates were estimated for all ten frames yielding 57.9±2.0 mL/s in comparison with 56.2 mL/s measured by a commercial magnetic flow meter. One frame of the obtained 3D vector flow data is presented and visualized using three alternative approaches. Practically no in-plane motion (v_x and v_z) is measured, whereas the out-of-plane motion (v_y) and the velocity magnitude exhibit the expected 2D circular-symmetric parabolic shape. It shown that the ultrasound method is suitable for real-time data acquisition as opposed to magnetic resonance imaging (MRI). The results demonstrate that the 3D TO method is capable of performing 3D vector flow imaging.

Proceedings Article | 29 March 2013 Paper

A delta-sigma beamformer with integrated apodization

Borislav Tomov, Matthias Stuart, Martin Hemmsen, Jørgen Jensen

Proceedings Volume 8675, 86750R (2013) https://doi.org/10.1117/12.2006731

KEYWORDS: Phased arrays, Apodization, Signal to noise ratio, Ultrasonography, Modulators, Analog electronics, Interference (communication), Scanners, Image filtering, Filtering (signal processing)

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Showing 5 of 14 publications

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