High frequency nonlinear scattering from a micrometer to submicrometer sized lipid encapsulated contrast agent

Goertz, David E.; Frijlink, M.E.; Jong, Nico de; Steen, A.F.W. van der

doi:10.1016/j.ultrasmedbio.2006.01.002

Cited by 52 publications

(37 citation statements)

References 19 publications

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“…Currently, the subharmonic response is mostly used in high frequency imaging applications. 11,12 Subharmonic bubble responses were first described following experimental observations by Esche 13 already in 1952. Additional experimental work has been conducted to investigate the nature of this non-linear behavior 14,15 followed by several theoretical descriptions of subharmonic behavior of bubbles in a sound field.…”

Section: Introductionmentioning

confidence: 99%

Subharmonic behavior of phospholipid-coated ultrasound contrast agent microbubbles

Sijl

Dollet²,

Overvelde³

et al. 2010

The Journal of the Acoustical Society of America

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114

107

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Coated microbubbles, unlike tissue are able to scatter sound subharmonically. Therefore, the subharmonic behavior of coated microbubbles can be used to enhance the contrast in ultrasound contrast imaging. Theoretically, a threshold amplitude of the driving pressure can be calculated above which subharmonic oscillations of microbubbles are initiated. Interestingly, earlier experimental studies on coated microbubbles demonstrated that the threshold for these bubbles is much lower than predicted by the traditional linear viscoelastic shell models. This paper presents an experimental study on the subharmonic behavior of differently sized individual phospholipid coated microbubbles. The radial subharmonic response of the microbubbles was recorded with the Brandaris ultra high-speed camera as a function of both the amplitude and the frequency of the driving pulse. Threshold pressures for subharmonic generation as low as 5 kPa were found near a driving frequency equal to twice the resonance frequency of the bubble. An explanation for this low threshold pressure is provided by the shell buckling model proposed by Marmottant et al. [ J. Acoust. Soc. Am. 118, 3499-3505 (2005)]. It is shown that the change in the elasticity of the bubble shell as a function of bubble radius as proposed in this model, enhances the subharmonic behavior of the microbubbles. Coated microbubbles, unlike tissue are able to scatter sound subharmonically. Therefore, the subharmonic behavior of coated microbubbles can be used to enhance the contrast in ultrasound contrast imaging. Theoretically, a threshold amplitude of the driving pressure can be calculated above which subharmonic oscillations of microbubbles are initiated. Interestingly, earlier experimental studies on coated microbubbles demonstrated that the threshold for these bubbles is much lower than predicted by the traditional linear viscoelastic shell models. This paper presents an experimental study on the subharmonic behavior of differently sized individual phospholipid coated microbubbles. The radial subharmonic response of the microbubbles was recorded with the Brandaris ultra high-speed camera as a function of both the amplitude and the frequency of the driving pulse. Threshold pressures for subharmonic generation as low as 5 kPa were found near a driving frequency equal to twice the resonance frequency of the bubble. An explanation for this low threshold pressure is provided by the shell buckling model proposed by Marmottant et al. ͓J. Acoust. Soc. Am. 118, 3499-3505 ͑2005͔͒. It is shown that the change in the elasticity of the bubble shell as a function of bubble radius as proposed in this model, enhances the subharmonic behavior of the microbubbles.

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Section: Introductionmentioning

confidence: 99%

Subharmonic behavior of phospholipid-coated ultrasound contrast agent microbubbles

Sijl

Dollet²,

Overvelde³

et al. 2010

The Journal of the Acoustical Society of America

Self Cite

114

107

View full text Add to dashboard Cite

show abstract

“…The observation of harmonics was unexpected because few UCAs in the submicron size range are expected to exist in a given dose, and, from the theory of free bubbles, the expectation is that relatively high pressures would be required to excite a bubble nonlinearly with HFU. In subsequent studies, Goertz et al 10,11 also observed harmonic backscatter from Optison™ ͑GE Healthcare, Chalfont St. Giles, UK͒ and a Bracco agent ͑Princeton, NJ͒, although at a much weaker pressure level than observed with Definity®. Theoretical work by Allen et al 12 suggested that shell waves may contribute to high-frequency backscatter components in lipid-shelled UCAs.…”

Section: Introductionmentioning

confidence: 92%

Subharmonic analysis using singular-value decomposition of ultrasound contrast agents

Mamou

Ketterling

2009

The Journal of the Acoustical Society of America

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Ultrasound contrast agents ͑UCAs͒ are designed to be used below 10 MHz, but interest is growing in studying the response of agents to high-frequency ultrasound. In this study, the subharmonic response of polymer-shelled UCAs with a mean diameter of 1.1 m excited with 40-MHz tone-bursts of 1 -20 cycles was analyzed. UCAs were diluted in water and streamed through a flow phantom that permitted single-bubble backscatter events to be acquired at peak-negative pressures from 0.75 to 5.0 MPa. At each exposure condition, 1000 single-bubble-backscatter events were digitized. Subharmonic content at 20 MHz was screened using a conventional and a singular-value-decomposition ͑SVD͒ method. The conventional method evaluated each event spectrum individually while the SVD method treated the 1000-event data set at one time. A subharmonic score ͑SHS͒ indicative of how much subharmonic content a 1000-event data set contained was computed for both methods. Empirical-simulation results indicated that SHSs obtained from the two methods were linearly related. Also, experimental data with both methods indicated that subharmonic likelihood increased with pulse duration and peaked near 2 MPa. The SVD method also yielded quantitative information about subharmonic events not available with the conventional method.

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“…Moreover the subharmonic response is attenuated less than both the fundamental and higher harmonic bubble responses. Given the transducer bandwidth limitations, subharmonic imaging is particularly interesting for high frequency imaging applications [73,74]. Subharmonic bubble responses were first described following experimental observations by Esche [75] already in 1952.…”

Section: Introductionmentioning

confidence: 99%

Ultrasound contrast agents : dynamics of coated bubbles

Overvelde¹

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High frequency nonlinear scattering from a micrometer to submicrometer sized lipid encapsulated contrast agent

Cited by 52 publications

References 19 publications

Subharmonic behavior of phospholipid-coated ultrasound contrast agent microbubbles

Subharmonic behavior of phospholipid-coated ultrasound contrast agent microbubbles

Subharmonic analysis using singular-value decomposition of ultrasound contrast agents

Ultrasound contrast agents : dynamics of coated bubbles

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