Mr. Carlos A. Villagomez Hoyos Profile

Carlos A. Villagomez Hoyos

at Technical Univ of Denmark

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Author

Publications (4)

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

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

Preliminary investigation of an ultrasound method for estimating pressure changes in deep-positioned vessels

Jacob Bjerring Olesen, Carlos Armando Villagomez-Hoyos, Marie Sand Traberg, Adrian J. Chee, Billy Y. Yiu, Chung Kit Ho, Alfred C. Yu, Jørgen Arendt Jensen

Proceedings Volume 9790, 97900J (2016) https://doi.org/10.1117/12.2214974

KEYWORDS: Ultrasonography, Phased arrays, Transducers, 3D modeling, Scanners, Numerical simulations, Medicine, Biology, Ultrafast imaging, Heart, Data modeling, Signal to noise ratio, Synthetic aperture radar

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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.

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