Riding the Plane Wave: Considerations for In Vivo Study Designs Employing High Frame Rate Ultrasound

Au, Jason S.; Hughson, Richard L.; Yu, Alfred C. H.

doi:10.3390/app8020286

Cited by 9 publications

(6 citation statements)

References 85 publications

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“…On the topic of RF data access, one important feature shared by different types of ultrasound OPs is that they possess tens and hundreds of gigabytes of RAM to store full RF data frames over multiple heart beats. Such raw data storage capacity makes it possible for researchers to conduct in vivo studies with OPs by acquiring multibeat in vivo data [110] and storing these data sets for offline processing. No restrictions are then enforced on the complexity of the processing, and the image videos can later be evaluated by medical doctors for multiple patients in double blinded trials as described in [111] .…”

Section: Discussionmentioning

confidence: 99%

Ultrasound Open Platforms for Next-Generation Imaging Technique Development

Boni

Freear

et al. 2018

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

118

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Open platform (OP) ultrasound systems are aimed primarily at the research community. They have been at the forefront of the development of synthetic aperture, plane wave, shear wave elastography, and vector flow imaging. Such platforms are driven by a need for broad flexibility of parameters that are normally preset or fixed within clinical scanners. OP ultrasound scanners are defined to have three key features including customization of the transmit waveform, access to the prebeamformed receive data, and the ability to implement real-time imaging. In this paper, a formative discussion is given on the development of OPs from both the research community and the commercial sector. Both software- and hardware-based architectures are considered, and their specifications are compared in terms of resources and programmability. Software-based platforms capable of real-time beamforming generally make use of scalable graphics processing unit architectures, whereas a common feature of hardware-based platforms is the use of field-programmable gate array and digital signal processor devices to provide additional on-board processing capacity. OPs with extended number of channels (>256) are also discussed in relation to their role in supporting 3-D imaging technique development. With the increasing maturity of OP ultrasound scanners, the pace of advancement in ultrasound imaging algorithms is poised to be accelerated.

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Section: Discussionmentioning

confidence: 99%

Ultrasound Open Platforms for Next-Generation Imaging Technique Development

Boni

Freear

et al. 2018

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

118

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“…For each acquired dataset, parallel beamforming and signal processing were performed in Matlab (R2016a; Mathworks Inc., Natick, MA, USA) . In brief, the received radiofrequency data were input to generate image frames with different receive steering angles, forming six unique transmit–receive angle pair images for each frame.…”

Section: Methodsmentioning

confidence: 99%

“…For each acquired dataset, parallel beamforming and signal processing were performed in Matlab (R2016a; Mathworks Inc., Natick, MA, USA). 19,32 In brief, the received radiofrequency data were input to generate image frames with different receive steering angles, forming six unique transmit-receive angle pair images for each frame. For each of these sets, slow-time processing was conducted on a per pixel basis including clutter suppression, mean Doppler frequency estimation, and manual dealiasing.…”

Section: C1 Flow Vector Estimation and Dynamic Visualizationmentioning

confidence: 99%

Ultrasound vector projectile imaging for detection of altered carotid bifurcation hemodynamics during reductions in cardiac output

Yiu

So³

et al. 2019

Medical Physics

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Purpose Complex blood flow is commonly observed in the carotid bifurcation, although the factors that regulate these patterns beyond arterial geometry are unknown. The emergence of high‐frame‐rate ultrasound vector flow imaging allows for noninvasive, time‐resolved analysis of complex hemodynamic behavior in humans, and it can potentially help researchers understand which physiological stressors can alter carotid bifurcation hemodynamics in vivo. Here, we seek to pursue the first use of vector projectile imaging (VPI), a dynamic form of vector flow imaging, to analyze the regulation of carotid bifurcation hemodynamics during experimental reductions in cardiac output induced via a physiological stressor called lower body negative pressure (LBNP). Methods Seven healthy adults (age: 27 ± 4 yr, 4 men) underwent LBNP at −45 mmHg to simulate a postural hemodynamic response in a controlled environment. Using a research‐grade, high‐frame‐rate ultrasound platform, vector flow estimation in each subject’s right carotid bifurcation was performed through a multi‐angle plane wave imaging (two transmission angles of 10° and −10°) formulation, and VPI cineloops were generated at a frame rate of 750 fps. Vector concentration was quantified by the resultant blood velocity vector angles within a region of interest; lower concentration indicated greater flow dispersion. Discrete concentration values during peak and late systole were compared across different segments of the carotid artery bifurcation before, and during, LBNP. Results Vector projectile imaging revealed that external and internal carotid arteries exhibited regional hemodynamic changes during LBNP, which acted to reduce both the subject’s cardiac output (Δ − 1.2 ± 0.5 L/min, −19%; P < 0.01) and peak carotid blood velocity (Δ − 6.30 ± 8.27 cm/s, −7%; P = 0.05). In these carotid artery branches, the vector concentration time trace before and during LBNP were observed to be different. The impact of LBNP on flow complexity in the two carotid artery branches showed variations between subjects. Conclusions Using VPI, intuitive visualization of complex hemodynamic changes can be obtained in healthy humans subjected to LBNP. This imaging tool has potential for further applications in vascular physiology to identify and quantify complex hemodynamic features in humans during different physiological stressor tests that regulate hemodynamics.

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“…In this Case Study in Physiology, we report incidental findings from a recent experiment in which we observed a femoral "trifurcation" at rest, and during experimental manipulation of retrograde blood flow in the SFA to induce highly complex hemodynamic behavior at the femoral branching point. While conventional ultrasound imaging is unable to quantify blood velocity within bifurcations due to nonlaminar blood flow, our laboratory has refined the vector flow imaging technique (5,7) to visualize and quantify angle-independent blood velocity vectors at high frame rates (Ͼ1,000 fps) to better characterize multidirectional blood flow features (2,17,18). These emerging techniques are highly relevant to study complex hemodynamics in atherosclerotic-prone regions such as arterial bifurcations, as in the specific case of the femoral arterial branches.…”

Section: Introductionmentioning

confidence: 99%

Case Studies in Physiology: Visualization of blood recirculation in a femoral artery “trifurcation” using ultrasound vector flow imaging

Yiu

2019

Journal of Applied Physiology

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The femoral bifurcation is typically composed of a common femoral artery that bifurcates into the superficial (SFA) and deep (DFA) femoral arteries, with the lateral circumflex femoral artery (LCFA) branching distal to the origin of the DFA. We report a unique case of a 22-yr-old woman with a femoral “trifurcation,” where the origin of the LCFA coincides with the origin of the DFA, resulting in a true three-way branching of the common femoral artery. We characterized the complex hemodynamics of the trifurcation region with ultrasound vector flow imaging at rest, and during 80 mmHg cuff compression of the calf to induce greater oscillatory blood flow. At rest, a clear trifurcation is observed with color Doppler imaging, while vector flow imaging further revealed a large area of flow circulation proximal to the LCFA and DFA. Cuff compression reduced SFA blood flow to 0 cm3/min, characterized by almost constant retrograde blood flow throughout diastole. When visualized with vector flow imaging, diastolic retrograde blood flow from the SFA appeared to reperfuse the DFA and LCFA during late systole, eliminating the retrograde flow component and providing a secondary source of anterograde blood flow to the thigh. In a rare case of a femoral trifurcation, we demonstrate blood recirculation patterns at rest, as well as collateral retrograde blood flow redistribution during lower limb compression. While it is unknown whether these trifurcation findings extend to typical bifurcations, it is evident that advanced methods of blood flow characterization are necessary to visualize and study complex vascular regions. NEW & NOTEWORTHY A femoral “trifurcation” is observed when the lateral circumflex femoral artery has an atypical proximal origin, branching at the same level as the superficial and deep femoral arteries. Ultrasound vector flow imaging at 750 fps was able to reveal substantial blood recirculation within the trifurcation at rest, as well as unique redistribution of blood flow between downstream branches during external cuff manipulation of retrograde flow, indicating novel ways in which diastolic blood flow is controlled.

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Riding the Plane Wave: Considerations for In Vivo Study Designs Employing High Frame Rate Ultrasound

Cited by 9 publications

References 85 publications

Ultrasound Open Platforms for Next-Generation Imaging Technique Development

Ultrasound Open Platforms for Next-Generation Imaging Technique Development

Ultrasound vector projectile imaging for detection of altered carotid bifurcation hemodynamics during reductions in cardiac output

Case Studies in Physiology: Visualization of blood recirculation in a femoral artery “trifurcation” using ultrasound vector flow imaging

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