Acoustic Properties of NC100100 and Their Relation With the Microbubble Size Distribution

Sontum, Per C.; Østensen, Jonny; Dyrstad, Knut; Hoff, Lars

doi:10.1097/00004424-199904000-00003

Cited by 90 publications

(56 citation statements)

References 9 publications

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“…The model-specific encapsulation parameters used in the numerical simulations are listed in Table I. Note that Sonazoid has a mean radius of 1.6lm (Hoff, 2001;Sontum et al, 1999). We find that for such a radius, none of the above-presented models predicts subharmonic response for excitation amplitudes, where it has been experimentally observed, i.e., the predicted subharmonic thresholds for this radius are much higher than the experimental observations.…”

Section: B Encapsulated Bubble Dynamicsmentioning

confidence: 82%

Excitation threshold for subharmonic generation from contrast microbubbles

Katiyar

Sarkar²

2011

The Journal of the Acoustical Society of America

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Six models of contrast microbubbles are investigated to determine the excitation threshold for subharmonic generation. The models are applied to a commercial contrast agent; its characteristic parameters according to each model are determined using experimentally measured ultrasound attenuation. In contrast to the classical perturbative result, the minimum threshold for subharmonic generation is not always predicted at excitation with twice the resonance frequency; instead it occurs over a range of frequencies from resonance to twice the resonance frequency. The quantitative variation of the threshold with frequency depends on the model and the bubble radius. All models are transformed into a common interfacial rheological form, where the encapsulation is represented by two radius dependent surface properties-effective surface tension and surface dilatational viscosity. Variation of the effective surface tension with radius, specifically having an upper limit (resulting from strain softening or rupture of the encapsulation during expansion), plays a critical role. Without the upper limit, the predicted threshold is extremely large, especially near the resonance frequency. Having a lower limit on surface tension (e.g., zero surface tension in the buckled state) increases the threshold value at twice the resonance frequency, in some cases shifting the minimum threshold toward resonance.

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Section: B Encapsulated Bubble Dynamicsmentioning

confidence: 82%

Excitation threshold for subharmonic generation from contrast microbubbles

Katiyar

Sarkar²

2011

The Journal of the Acoustical Society of America

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“…35 We previously assessed several different US contrast agents for evaluations of the lymphatic system in a number of areas of the body (including subcutaneous, submucosal, and parenchymal injections) in a variety of animal models. 17 In addition to confirming that lymphosonography could be performed for a variety of lymphatic applications, the benefits of using a reticuloendothelialspecific agent such as Sonazoid for lymphatic applications became apparent during these investigations.…”

Section: Discussionmentioning

confidence: 99%

Contrast-Enhanced Ultrasound Imaging of Sentinel Lymph Nodes After Peritumoral Administration of Sonazoid in a Melanoma Tumor Animal Model

Goldberg

Merton

Liu

et al. 2011

Journal of Ultrasound in Medicine

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etection and characterization of sentinel lymph nodes (SLNs) are important for the management of patients who have a variety of malignancies, including melanoma, breast, colon, and other cancers. [1][2][3][4] Various techniques and imaging agents have been developed to map lymphatic drainage from tumors, including the use of blue dye with surgical dissection and injection of radiopharmaceuticals followed by evaluation with a gamma camBarry B. Goldberg, MD, Daniel A. Merton, BS, RDMS, Ji-Bin Liu, MD, Flemming Forsberg, PhD, Kaijun Zhang, PhD, Madhukar Thakur, PhD, Stephanie Schulz, PhD, Robin Schanche, BS, George F. Murphy, MD, Scott A. Waldman, MD, PhD Received October 6, 2010, ORIGINAL RESEARCHObjectives-The purpose of this study was to compare lymphosonography (ie, contrast-enhanced ultrasound imaging [US] after interstitial injection of a US contrast agent) for the detection of sentinel lymph nodes (SLNs) in swine with naturally occurring melanoma tumors to lymphoscintigraphy using blue dye-guided surgical dissection as the reference standard. Also, we sought to determine if lymphosonography can be used to characterize SLNs.Methods-Sixty-three swine with 104 melanomas were evaluated. Contrast-specific US was performed after peritumoral injection (1 mL dose) of Sonazoid (GE Healthcare, Oslo, Norway). Lymphoscintigraphy was performed after peritumoral injections of technetium Tc 99m sulfur colloid. Peritumoral injection of 1% Lymphazurin (Ben Venue Labs, Inc, Bedford, OH) was used to guide SLN resection. The accuracy of SLN detection with the two imaging modalities was compared using the McNemar test. The SLNs were qualitatively and quantitatively characterized as benign or malignant based on the lymphosonography results with histopathology and RNA analyses used as the reference standards.Results-Blue dye-guided surgery identified 351 SLNs. Lymphosonography detected 293 SLNs and 11 false-positives, while lymphoscintigraphy detected 231 SLNs and 20 false-positives. The accuracy of SLN detection was 81.8% for lymphosonography, which was significantly higher than the 63.2% achieved with lymphoscintigraphy (P < .0001). The accuracy of lymphosonography for SLN characterization was 80%. When the size of the enhanced SLN was taken into consideration to characterize SLNs, the accuracy was 86%.Conclusions-Lymphosonography is statistically better than lymphoscintigraphy for the detection of SLNs in this animal model. The ability to use lymphosonography as a means to characterize SLNs as benign or malignant is limited.

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“…Sonazoid has a relatively narrow size distribution with an average mean diameter of 3.2Ϯ 0.2 m with a number concentration of 0.78Ϯ 0.38 billions/ ml. 36 We have used both the radius distribution 37 as well as the average radius value obtaining essentially the same characteristic values for the encapsulation. To find the characteristic parameters pertaining to a model, an error function between the measured attenuation and the model attenuation is used as follows:…”

Section: ͑16͒mentioning

confidence: 99%

Material characterization of the encapsulation of an ultrasound contrast microbubble and its subharmonic response: Strain-softening interfacial elasticity model

Paul

Katiyar

Sarkar

et al. 2010

The Journal of the Acoustical Society of America

115

136

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Two nonlinear interfacial elasticity models-interfacial elasticity decreasing linearly and exponentially with area fraction-are developed for the encapsulation of contrast microbubbles. The strain softening ͑decreasing elasticity͒ results from the decreasing association between the constitutive molecules of the encapsulation. The models are used to find the characteristic properties ͑surface tension, interfacial elasticity, interfacial viscosity and nonlinear elasticity parameters͒ for a commercial contrast agent. Properties are found using the ultrasound attenuation measured through a suspension of contrast agent. Dynamics of the resulting models are simulated, compared with other existing models and discussed. Imposing non-negativity on the effective surface tension ͑the encapsulation experiences no net compressive stress͒ shows "compression-only" behavior. The exponential and the quadratic ͑linearly varying elasticity͒ models result in similar behaviors. The validity of the models is investigated by comparing their predictions of the scattered nonlinear response for the contrast agent at higher excitations against experimental measurement. All models predict well the scattered fundamental response. The nonlinear strain softening included in the proposed elastic models of the encapsulation improves their ability to predict subharmonic response. They predict the threshold excitation for the initiation of subharmonic response and its subsequent saturation.

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Acoustic Properties of NC100100 and Their Relation With the Microbubble Size Distribution

Cited by 90 publications

References 9 publications

Excitation threshold for subharmonic generation from contrast microbubbles

Excitation threshold for subharmonic generation from contrast microbubbles

Contrast-Enhanced Ultrasound Imaging of Sentinel Lymph Nodes After Peritumoral Administration of Sonazoid in a Melanoma Tumor Animal Model

Material characterization of the encapsulation of an ultrasound contrast microbubble and its subharmonic response: Strain-softening interfacial elasticity model

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