Harmonic chirp imaging method for ultrasound contrast agent

Borsboom, J.; Chin, Chien Ting; Bouakaz, Ayache; Versluis, Michel; Jong, Nico de

doi:10.1109/tuffc.2005.1406550

Cited by 95 publications

(60 citation statements)

References 11 publications

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“…They have also been implemented to improve the contrast to tissue ratio when imaging with microbubbles [41], [42]. It has been proposed that due to the polydisperse nature of microbubble populations, if the frequency range of the chirp were to match those of the resonant frequency of the population, a greater acoustic response could be achieved [43].…”

Section: Introductionmentioning

confidence: 99%

Increasing the sonoporation efficiency of targeted polydisperse microbubble populations using chirp excitation

McLaughlan

Ingram

Smith

et al. 2013

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

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Abstract-The therapeutic use of microbubbles for targeted drug or gene delivery is a highly active area of research. Phospholipid-encapsulated microbubbles typically have a polydisperse size distribution over the 1-10 µm range and can be functionalised for molecular targeting as well as loaded with drug-carrying liposomes. Sonoporation through the generation of shear stress on the cell membrane by microbubble oscillations is one mechanism that results in pore formation in the cell membrane and can improve drug delivery. A microbubble oscillating at its resonant frequency would generate maximum shear stress on a membrane. However, due to the polydisperse nature of phospholipid microbubbles, a range of resonant frequencies would exist in a single population. In this study, the use of linear chirp excitations was compared with equivalent duration and acoustic pressure tone excitations when measuring the sonoporation efficiency of targeted-microbubbles on human colorectal cancer cells. A 3-7 MHz chirp had the greatest sonoporation efficiency of 26.9 ±5.6 %, compared with 16.4 ±1.1 % for the 1.32-3.08 MHz chirp. The equivalent 2.2 and 5 MHz tone excitations have efficiencies of 12.8 ±2.1 % and 15.6 ±1.1 %, respectively, which were all above the efficiency of 4.1 ±3.1 % from the control exposure.

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Section: Introductionmentioning

confidence: 99%

Increasing the sonoporation efficiency of targeted polydisperse microbubble populations using chirp excitation

McLaughlan

Ingram

Smith

et al. 2013

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

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“…Long duration chirp signals are able to carry more energy without increasing the peak excitation pressure and without reducing the system frame-rate. A matched filter, whose impulse response is the time reversed complex conjugate of the excitation signal, is typically applied on the received signal to perform pulse compression to achieve high axial resolution [10], [11].…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation of chirp coded excitation in ultrasound superharmonic imaging

Arif

Harput

Freear

2010

2010 IEEE International Ultrasonics Symposium

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Abstract-Superharmonic imaging (SHI) provides improved spatial resolution and contrast detection with low reverberation artifacts by combining the third, fourth and fifth harmonics of the nonlinear received signal. The aim of this study is to increase the signal-to-noise ratio (SNR) with improved axial resolution and reduced ripple artifacts in the SHI using chirp coded excitation. Experiments are performed using a 2.25 MHz transducer mounted coaxially at a distance of 1-10 cm with a 0.2 mm hydrophone in a tank containing deionised, degassed water. The applied linear chirp signals have 10 µsec duration, and fractional bandwidths (FBW) of 20% and 40%. In the experiments, the 2.25 MHz tone-burst signal of same duration is used for comparison. The pressure level of each waveform is calibrated and the mechanical index of 0.75 is set at the focus of the transducer. The harmonic matched filtering is applied to the received signal to perform pulse compression of the individual harmonic chirp components to recover axial resolution. To get the superharmonic chirp, the third to fifth harmonic components are combined after pulse compression. To avoid ripple artifacts in the superharmonic component of the tone-burst, the envelopes of the individually filtered third, fourth and fifth harmonic signals are combined in the time domain. The results indicate that the compressed superharmonic chirp, under a 20% FBW chirp excitation, show a 35% reduction in the axial pulse width at -20 dB when compared with the superharmonic of a tone-burst. Similarly using a 40% FBW chirp excitation, 65% reduction in the pulse width of the compressed superharmonic chirp has been found when compared with the superharmonic of a tone-burst.

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“…Chirp-coded excitation is one such technique that has been widely investigated for contrast-enhanced ultrasound imaging. 14,[18][19][20][21][22][23][24][25][26][27] In a theoretical study, Barlow and colleagues reported an analytical solution to the Keller-Herring model, to predict the response of microbubbles to chirp-coded excitation. 18 A classical perturbative analysis was employed 28 to gain insight into the impact of excitation parameters on the nonlinear response.…”

Section: Introductionmentioning

confidence: 99%

“…Borsboom and colleagues assessed the impact of chirp-coded excitation on HI. [20][21][22] The feasibility of enhancing the subharmonic response of UCA with chirp-coded excitation was demonstrated by Zhang and co-workers. 23 Shen and colleagues incorporated chirp-coding into dual frequency difference excitation imaging to excite UCAs close to their resonance frequency.…”

Section: Introductionmentioning

confidence: 99%

The response of phospholipid-encapsulated microbubbles to chirp-coded excitation: Implications for high-frequency nonlinear imaging

Shekhar

Doyley

2013

The Journal of the Acoustical Society of America

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The current excitation strategy for harmonic and subharmonic imaging (HI and SHI) uses short sinebursts. However, alternate pulsing strategies may be useful for enhancing nonlinear emissions from ultrasound contrast agents. The goal of this study was to corroborate the hypothesis that chirp-coded excitation can improve the performance of high-frequency HI and SHI. A secondary goal was to understand the mechanisms that govern the response of ultrasound contrast agents to chirp-coded and sine-burst excitation schemes. Numerical simulations and acoustic measurements were conducted to evaluate the response of a commercial contrast agent (Targestar-P V R ) to chirp-coded and sine-burst excitation (10 MHz frequency, peak pressures 290 kPa). The results of the acoustic measurements revealed an improvement in signal-to-noise ratio by 4 to 14 dB, and a two-to threefold reduction in the subharmonic threshold with chirp-coded excitation. Simulations conducted with the Marmottant model suggest that an increase in expansion-dominated radial excursion of microbubbles was the mechanism responsible for the stronger nonlinear response. Additionally, chirp-coded excitation detected the nonlinear response for a wider range of agent concentrations than sine-bursts. Therefore, chirp-coded excitation could be a viable approach for enhancing the performance of HI and SHI.

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Harmonic chirp imaging method for ultrasound contrast agent

Cited by 95 publications

References 11 publications

Increasing the sonoporation efficiency of targeted polydisperse microbubble populations using chirp excitation

Increasing the sonoporation efficiency of targeted polydisperse microbubble populations using chirp excitation

Experimental investigation of chirp coded excitation in ultrasound superharmonic imaging

The response of phospholipid-encapsulated microbubbles to chirp-coded excitation: Implications for high-frequency nonlinear imaging

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