Quantification of transpulmonary echocontrast effects

Jong, Nico de; Cate, Folkert J. ten; Vletter, W. B.; Roelandt, Jos R.T.C.

doi:10.1016/0301-5629(93)90100-3

Cited by 40 publications

(19 citation statements)

References 20 publications

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“…Effects on diffusion/destruction. De Jong et al [49] observed that albumin bubbles tend to shrink and disappear if a hydrostatic pressure of about 0.2 atm (20 kPa) is applied. This disappearance is attributed to passive dissolution.…”

Section: Blood Pressurementioning

confidence: 99%

Quantitative contrast-enhanced ultrasound imaging: a review of sources of variability

Tang

Mulvana

Gauthier³

et al. 2011

Interface Focus.

262

219

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Ultrasound provides a valuable tool for medical diagnosis offering real-time imaging with excellent spatial resolution and low cost. The advent of microbubble contrast agents has provided the additional ability to obtain essential quantitative information relating to tissue vascularity, tissue perfusion and even endothelial wall function. This technique has shown great promise for diagnosis and monitoring in a wide range of clinical conditions such as cardiovascular diseases and cancer, with considerable potential benefits in terms of patient care. A key challenge of this technique, however, is the existence of significant variations in the imaging results, and the lack of understanding regarding their origin. The aim of this paper is to review the potential sources of variability in the quantification of tissue perfusion based on microbubble contrast-enhanced ultrasound images. These are divided into the following three categories: (i) factors relating to the scanner setting, which include transmission power, transmission focal depth, dynamic range, signal gain and transmission frequency, (ii) factors relating to the patient, which include body physical differences, physiological interaction of body with bubbles, propagation and attenuation through tissue, and tissue motion, and (iii) factors relating to the microbubbles, which include the type of bubbles and their stability, preparation and injection and dosage. It has been shown that the factors in all the three categories can significantly affect the imaging results and contribute to the variations observed. How these factors influence quantitative imaging is explained and possible methods for reducing such variations are discussed.

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Section: Blood Pressurementioning

confidence: 99%

Quantitative contrast-enhanced ultrasound imaging: a review of sources of variability

Tang

Mulvana

Gauthier³

et al. 2011

Interface Focus.

262

219

View full text Add to dashboard Cite

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“…De Jong et al [37], estimated the size distribution of ultrasound contrast agents that pass through the lungs based on the size distribution of the pulmonary capillaries [38]. The same technique was applied to estimate the size distribution of droplets that would pass through the lung.…”

Section: Centrifugation Of Dropletsmentioning

confidence: 99%

“…The largest sized droplets within a centrifuged emulsion depends on the centrifugation speed and duration [39,40]. An optimal size distribution of centrifuged droplets could be found which would enable a higher percentage of droplets to pass through the pulmonary capillaries [37]. Figure 6b, the centrifuged droplets without ultrasound exposure did not cause a significant decrease in the DO of the surrounding fluid, whereas non-centrifuged droplets without ultrasound exposure did cause a significant decrease in the DO of the surrounding fluid (Figure 4).…”

Section: Effect Of Centrifugation On the Droplet Size Distribution Anmentioning

confidence: 99%

Scavenging dissolved oxygen via acoustic droplet vaporization

Radhakrishnan

Holland

Haworth

2014

The Journal of the Acoustical Society of America

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Acoustic droplet vaporization (ADV) of perfluorocarbon emulsions has been explored for diagnostic and therapeutic applications. Previous studies have demonstrated that vaporization of a liquid droplet results in a gas microbubble with a diameter 5 to 6 times larger than the initial droplet diameter. The expansion factor can increase to a factor of 10 in gassy fluids as a result of air diffusing from the surrounding fluid into the microbubble. This study investigates the potential of this process to serve as an ultrasound-mediated gas scavenging technology. Perfluoropentane droplets diluted in phosphate-buffered saline (PBS) were insonified by a 2 MHz transducer at peak rarefactional pressures lower than and greater than the ADV pressure amplitude threshold in an in vitro flow phantom. The change in dissolved oxygen (DO) of the PBS before and after ADV was measured. A numerical model of gas scavenging, based on conservation of mass and equal partial pressures of gases at equilibrium, was developed. At insonation pressures exceeding the ADV threshold, the DO of air-saturated PBS decreased with increasing insonation pressures, dropping as low as 25% of air saturation within 20 s. The decrease in DO of the PBS during ADV was dependent on the volumetric size distribution of the droplets and the fraction of droplets transitioned during ultrasound exposure. Numerically predicted changes in DO from the model agreed with the experimentally measured DO, indicating that concentration gradients can explain this phenomenon. Using computationally modified droplet size distributions that would be suitable for in vivo applications, the DO of the PBS was found to decrease with increasing concentrations. This study demonstrates that ADV can significantly decrease the DO in an aqueous fluid, which may have direct therapeutic applications and should be considered for ADV-based diagnostic or therapeutic applications.

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“…1 Current techniques for fabricating perfluorocarbon droplets, such as sonication, 4 high-speed mechanical shaking, 1,3 and condensation, 2 produce polydisperse size distributions ranging from hundreds of nanometers to tens of micrometers in diameter. However, droplets greater than approximately 8 lm in diameter are too large to pass through the pulmonary capillaries following intravenous injection, 6 and droplets smaller than 3 lm in diameter require more ultrasound energy to phase transition compared to larger droplets. 2,3,7 Thus, methods are needed to isolate droplets that are small enough to pass through capillary beds and are large enough to phase transition efficiently.…”

Section: Introductionmentioning

confidence: 99%

Size-isolation of ultrasound-mediated phase change perfluorocarbon droplets using differential centrifugation

Mercado

Radhakrishnan

Stewart

et al. 2016

The Journal of the Acoustical Society of America

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Perfluorocarbon droplets that are capable of an ultrasound-mediated phase transition have applications in diagnostic and therapeutic ultrasound. Techniques to modify the droplet size distribution are of interest because of the size-dependent acoustic response of the droplets. Differential centrifugation has been used to isolate specific sizes of microbubbles. In this work, differential centrifugation was employed to isolate droplets with diameters between 1 and 3 μm and 2 and 5 μm from an initially polydisperse distribution. Further, an empirical model was developed for predicting the droplet size distribution following differential centrifugation and to facilitate the selection of centrifugation parameters for obtaining desired size distributions.

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Quantification of transpulmonary echocontrast effects

Cited by 40 publications

References 20 publications

Quantitative contrast-enhanced ultrasound imaging: a review of sources of variability

Quantitative contrast-enhanced ultrasound imaging: a review of sources of variability

Scavenging dissolved oxygen via acoustic droplet vaporization

Size-isolation of ultrasound-mediated phase change perfluorocarbon droplets using differential centrifugation

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