New clutter rejection method using time-domain averaging for ultrasound color Doppler imaging

Lee, Jaejin; Cho, Jeong; Yoo, Yangmo; Song, Tai-Kyong

doi:10.1109/ultsym.2009.5441639

Cited by 3 publications

(4 citation statements)

References 4 publications

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“…The TDA approach could represent an alternative option for extracting the signal from smaller droplets. The efficiency of TDA has already been demonstrated to reject clutter during color Doppler imaging [42], and it has been shown here to reduce both the microbubble response at 1 MHz.…”

Section: Discussionmentioning

confidence: 71%

“…The five RF lines received at each location were averaged, and then the average RF line was subtracted from each individual receive line prior to envelope detection and energy calculations. This technique has been studied as a way to reject clutter during color Doppler imaging [42], as signals that are relatively constant and appear in each receive line are removed. In the case of droplet activation, vaporization signals vary in amplitude, frequency, and phase to a greater extent than microbubble and tissue signals received at 1/8 the insonification frequency.…”

Section: Methodsmentioning

confidence: 99%

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Dual-frequency acoustic droplet vaporization detection for medical imaging

Arena

Novell

Sheeran

et al. 2015

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

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Liquid-filled perfluorocarbon droplets emit a unique acoustic signature when vaporized into to gas-filled microbubbles using ultrasound. Here, we conducted a pilot study in a tissue-mimicking flow phantom to explore the spatial aspects of droplet vaporization and investigate the effects of applied pressure and droplet concentration on image contrast and axial and lateral resolution. Control microbubble contrast agents were used for comparison. A confocal dual-frequency transducer was used to transmit at 8 MHz and passively receive at 1 MHz. Droplet signals were of significantly higher energy than microbubble signals. This resulted in improved signal separation and high contrast-to-tissue ratios (CTR). Specifically, with a peak negative pressure (PNP) of 450 kPa applied at the focus, the CTR of B-mode images was 18.3 dB for droplets and −0.4 for microbubbles. The lateral resolution was dictated by the size of the droplet activation area, with lower pressures resulting in smaller activation areas and improved lateral resolution (0.67 mm at 450 kPa). The axial resolution in droplet images was dictated by the size of the initial droplet and independent of the properties of the transmit pulse (3.86 mm at 450 kPa). In post-processing, time-domain averaging (TDA) improved droplet and microbubble signal separation at high pressures (640 kPa and 700 kPa). Taken together, these results indicate that it is possible to generate high-sensitivity, high-contrast images of vaporization events. In the future, this has the potential to be applied in combination with droplet-mediated therapy to track treatment outcomes or as a stand-alone diagnostic system to monitor the physical properties of the surrounding environment.

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Section: Discussionmentioning

confidence: 71%

Section: Methodsmentioning

confidence: 99%

Dual-frequency acoustic droplet vaporization detection for medical imaging

Arena

Novell

Sheeran

et al. 2015

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

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“…Multiple reflections from the transmitted burst inside the wall superimpose the signal from scatter particles in the vicinity of the wall. For this problem, a multitude of signal-processing methods were proposed, most of them based on digital filters (finite impulse response (FIR) or infinite impulse response (IIR) filters) with various initialization techniques (Lee et al, 2009). With these methods, the clutter is distinguished from the particle echoes by a velocity close to zero, respectively, by a Doppler frequency shift close to zero.…”

Section: Clutter-reduction Filteringmentioning

confidence: 99%

Measurement uncertainty analysis of field-programmable gate-array-based, real-time signal processing for ultrasound flow imaging

Nauber

Büttner

Czarske

2020

J. Sens. Sens. Syst.

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Abstract. Research in magnetohydrodynamics (MHD) aims to understand the complex interactions of electrically conductive fluids and magnetic fields. A promising approach for investigating complex instationary flow phenomena are lab-scale experiments with low-melting alloys. They require a noninvasive flow instrumentation for opaque liquids with a high spatiotemporal resolution, a low velocity uncertainty and a long measurement duration. Ultrasound Doppler velocimetry can achieve multiplane, multicomponential flow imaging with multiple linear ultrasound arrays. However the average raw data output amounts to 1.2 GBs−1 at a frame rate of 33 Hz in a typical configuration for 200 transducers. This usually prevents long-duration measurements when offline signal processing is used. In this paper, we propose an online signal-processing chain for pulsed-wave Doppler velocimetry that is tailored to the specific requirements of flow imaging for lab-scale experiments. The trade-off between measurement uncertainty and computational complexity is evaluated for different algorithmic variants in relation to the Cramér–Rao bound. By utilizing selected approximations and parameter choices, a prepossessing could be efficiently implemented on a field-programmable gate array (FPGA), enabling a typical reduction of the data bandwidth of 6.5:1 and online flow visualization. We validated the performance of the signal processing on a test rig, yielding a velocity standard deviation that is a factor of 3 above the theoretical limit despite a low computational complexity. Potential applications for this signal processing include multihour flow measurements during a crystal-growth process and closed-loop velocity feedback for model experiments.

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“…The five RF lines received at each location were averaged, and then the average RF line was subtracted from each individual receive line prior to energy calculations. This technique has been studied as a way to reject clutter during color Doppler imaging [15], as signals that are relatively constant and appear in each receive line are removed. In the case of PCCA activation, vaporization signals vary in amplitude and frequency to a greater extent than microbubble signals received at 1/8 the insonification frequency.…”

Section: Image Processingmentioning

confidence: 99%

Ultrasound imaging from vaporization signals emitted by phase change contrast agents

Arena

Novell

Sheeran

et al. 2014

2014 IEEE International Ultrasonics Symposium

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Phase change contrast agents (PCCAs) exhibit a unique acoustic signature during the transition from a liquid droplet to a gas microbubble. Here, we demonstrate that this event can be used to generate an ultrasound image, and that the signal can be separated from that of a conventional microbubble. This presents a new opportunity to monitor PCCA activation in both diagnostic and therapeutic applications. A confocal, dualfrequency transducer was used to transmit 2 cycle, Gaussian enveloped sinusoids at 8 MHz and passively receive at 1 MHz. PCCAs were continuously infused through a microcellulose tube (250 μm diameter). At low pressures, vaporization signals from PCCAs were of significantly higher energy than signals emitted from the equivalent microbubble formulation. Specifically, when a peak negative pressure (PNP) of 0.51 MPa was transmitted, the contrast-to-noise ratio (CNR) was 18.94 dB for PCCAs and 2.28 dB for control microbubbles. As the PNP was increased to 0.76 MPa, these values changed to 22.1 dB and 9.73 dB, respectively. Time-domain averaging (TDA) helped to increase the separation of PCCA and microbubble signals. After TDA, the CNR at 0.76 MPa was 23.79 dB for PCCAs and 1.72 dB for microbubbles. The lateral resolution of the system was pressure dependent. With increasing pressure, the apparent diameter of the tube increased from 0.74 mm at 0.51 MPa to 1.14 mm at 0.76 MPa. This is due to the fact that the focal zone capable of activating PCCAs expands with increasing pressure.

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New clutter rejection method using time-domain averaging for ultrasound color Doppler imaging

Cited by 3 publications

References 4 publications

Dual-frequency acoustic droplet vaporization detection for medical imaging

Dual-frequency acoustic droplet vaporization detection for medical imaging

Measurement uncertainty analysis of field-programmable gate-array-based, real-time signal processing for ultrasound flow imaging

Ultrasound imaging from vaporization signals emitted by phase change contrast agents

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