On the acoustic response of microbubbles in arteriole sized vessels

Butler, Mairéad; Thomas, David Hurst; Silva, Nádia; Pye, S. D.; Sboros, Vassilis

doi:10.1063/1.3657519

Cited by 7 publications

(3 citation statements)

References 19 publications

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“…Thus, this method can be applied to CEUS. The model-based approach allows the inclusion of prior knowledge on the evolution of MB signals [45][46][47][48][49][50] that may lead to more efficient tracking. Emphasis is given to the detection and segmentation.…”

Section: Super-resolution Contrast-enhanced Ultrasound Methodology For the Identification Of In Vivo Vascular Dynamics In 2dmentioning

confidence: 99%

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Super-Resolution Contrast-Enhanced Ultrasound Methodology for the Identification of In Vivo Vascular Dynamics in 2D

Kanoulas¹,

Butler²,

Rowley

et al. 2019

Invest Radiol

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Objectives The aim of this study was to provide an ultrasound-based super-resolution methodology that can be implemented using clinical 2-dimensional ultrasound equipment and standard contrast-enhanced ultrasound modes. In addition, the aim is to achieve this for true-to-life patient imaging conditions, including realistic examination times of a few minutes and adequate image penetration depths that can be used to scan entire organs without sacrificing current super-resolution ultrasound imaging performance. Methods Standard contrast-enhanced ultrasound was used along with bolus or infusion injections of SonoVue (Bracco, Geneva, Switzerland) microbubble (MB) suspensions. An image analysis methodology, translated from light microscopy algorithms, was developed for use with ultrasound contrast imaging video data. New features that are tailored for ultrasound contrast image data were developed for MB detection and segmentation, so that the algorithm can deal with single and overlapping MBs. The method was tested initially on synthetic data, then with a simple microvessel phantom, and then with in vivo ultrasound contrast video loops from sheep ovaries. Tracks detailing the vascular structure and corresponding velocity map of the sheep ovary were reconstructed. Images acquired from light microscopy, optical projection tomography, and optical coherence tomography were compared with the vasculature network that was revealed in the ultrasound contrast data. The final method was applied to clinical prostate data as a proof of principle. Results Features of the ovary identified in optical modalities mentioned previously were also identified in the ultrasound super-resolution density maps. Follicular areas, follicle wall, vessel diameter, and tissue dimensions were very similar. An approximately 8.5-fold resolution gain was demonstrated in vessel width, as vessels of width down to 60 μm were detected and verified (λ = 514 μm). Best agreement was found between ultrasound measurements and optical coherence tomography with 10% difference in the measured vessel widths, whereas ex vivo microscopy measurements were significantly lower by 43% on average. The results were mostly achieved using video loops of under 2-minute duration that included respiratory motion. A feasibility study on a human prostate showed good agreement between density and velocity ultrasound maps with the histological evaluation of the location of a tumor. Conclusions The feasibility of a 2-dimensional contrast-enhanced ultrasound-based super-resolution method was demonstrated using in vitro, synthetic and in vivo animal data. The method reduces the examination times to a few minutes using state-of-the-art ultrasound equipment and can provide super-resolution maps for an entire prostate with similar resolution to that achieved in other studies.

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Section: Super-resolution Contrast-enhanced Ultrasound Methodology For the Identification Of In Vivo Vascular Dynamics In 2dmentioning

confidence: 99%

“…This setup was based on previously described in vitro work. 47 The cellulose tube has a nominal internal diameter of 200 μm. Subsequently, and upon inspection using bright field microscopy, it was found to have a maximum internal diameter of 300 μm.…”

Section: In Vitro Imagingmentioning

confidence: 99%

Super-Resolution Contrast-Enhanced Ultrasound Methodology for the Identification of In Vivo Vascular Dynamics in 2D

Kanoulas¹,

Butler²,

Rowley

et al. 2019

Invest Radiol

Self Cite

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“…In terms of the experimental investigation of the effects of microbubble environment on its response, there is a much smaller body of work. Primarily, these studies have been limited to the investigation of the effects of rigid vessel diameter (mimicked by either a cellulose or a PMMA tube) on the response of microbubbles that lay adjacent to that boundary (Caskey et al 2006, Thomas et al 2013, Butler et al 2011. These studies employed fast-frame microscopy imaging to reveal that microbubble radial excursion amplitude can be larger in larger diameter vessels (≈200 μm) as compared to the smaller diameter ones (≈25 μm).…”

Section: Introductionmentioning

confidence: 99%

The effect of boundary proximity on the response of individual ultrasound contrast agent microbubbles

2014

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The effect of boundary proximity on ultrasound contrast agent microbubble emissions can play an important role in the context of both targeted microbubble imaging and contrast imaging of microvascular perfusion. In this study, individual microbubbles (n = 104) were insonicated as a function of distance from either a polystyrene membrane (Opticell(TM)) or a compliant agarose boundary up to offset distances of 1000 µm by use of an optical trapping setup. An 'acoustic spectroscopy' approach was employed, which entailed transmitting a sequence of tone bursts with centre frequencies ranging from 4 to 13.5 MHz to determine the frequency and amplitude of maximum radial response (fMR and AMR, respectively). For the Opticell(TM) case, microbubble response exhibited a distinctly oscillatory pattern with increasing offset distance, with an average maximal change in peak frequency and scattered pressure amplitude of 29.6% and 73.2%, respectively, as compared to their values adjacent to the boundary. For the agarose case, microbubbles exhibited an increase in fMR and a decrease in AMR with respect to their values in free space. Simulations indicate the oscillatory dependence on Opticell(TM) distance stems from wavelength-dependent interference phenomena. A recent analytical bubble-boundary model is in broad agreement with the relative AMR changes due to the more compliant agarose layer, however underestimates the change in relative fMR at the boundary.

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A Review of Phospholipid Encapsulated Ultrasound Contrast Agent Microbubble Physics

Helfield

2019

Ultrasound in Medicine & Biology

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On the acoustic response of microbubbles in arteriole sized vessels

Abstract: A simulation environment for validating ultrasonic blood flow and vessel wall imaging based on fluid-structure interaction simulations: Ultrasonic assessment of arterial distension and wall shear rate Med.

Cited by 7 publications

References 19 publications

Super-Resolution Contrast-Enhanced Ultrasound Methodology for the Identification of In Vivo Vascular Dynamics in 2D

Super-Resolution Contrast-Enhanced Ultrasound Methodology for the Identification of In Vivo Vascular Dynamics in 2D

The effect of boundary proximity on the response of individual ultrasound contrast agent microbubbles

A Review of Phospholipid Encapsulated Ultrasound Contrast Agent Microbubble Physics

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