Coded excitation for diagnostic ultrasound: a system developer's perspective

Chiao, Richard Y.; Hao, Xiaohui

doi:10.1109/ultsym.2003.1293440

Cited by 168 publications

(68 citation statements)

References 19 publications

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“…The use of linear frequency modulated chirps in diagnostic ultrasound imaging is a method for improving the signal-to-noise ratio and penetration depth of this imaging technique [38]- [40]. They have also been implemented to improve the contrast to tissue ratio when imaging with microbubbles [41], [42].…”

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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“…These coding techniques are now also well known in medical imaging and have been applied to clinical ultrasound systems to improve the SNR and penetration depth without increasing the peak acoustic pressure [32], [33]. In ultrasound systems with coded excitation, the signal coding schemes are based on either frequency modulation or phase modulation.…”

Section: Coded Excitation: Theory and Signal Designmentioning

confidence: 99%

The effect of amplitude modulation on subharmonic imaging with chirp excitation

Harput

Arif

McLaughlan

et al. 2013

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

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Abstract-Subharmonic generation from ultrasound contrast agents depends on the spectral and temporal properties of the excitation signal. The subharmonic response can be improved by using wideband and long duration signals. However, for sinusoidal tone-burst excitation the effective bandwidth of the signal is inversely proportional with the signal duration. Linear frequency modulated (LFM) and nonlinear frequency modulated (NLFM) chirp excitations allow independent control over the signal bandwidth and duration, therefore in this study LFM and NLFM signals were used for the insonation of microbubble populations. The amplitude modulation of the excitation waveform was achieved by applying different window functions. A customized window was designed for the NLFM chirp excitation by focusing on reducing the spectral leakage at the subharmonic frequency and increasing the subharmonic generation from microbubbles.Subharmonic scattering from a microbubble population was measured for various excitation signals and window functions. At a peak-negative pressure of 600 kPa, the generated subharmonic energy by ultrasound contrast agents was 15.4 dB more for NLFM chirp excitation with 40% fractional bandwidth when compared to tone-burst excitation. For this reason, the NLFM chirp with a customized window was used as an excitation signal to perform subharmonic imaging in an ultrasound flow phantom. Results showed that the NLFM waveform with a customized window improved the subharmonic contrast by 4.35 ± 0.42 dB on average over a Hann windowed LFM excitation.

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“…Medical ultrasonic systems have seen widespread interest in pulse compression systems, Misaridis published a comprehensive introduction series to medical pulse compression [6,7,8] whilst other introduction and developers guides have been published [9,10]. Bridging the gap between NDT and medical systems have been papers monitoring bone thickness and density [11,12].…”

Section: Insert Figure 2 Herementioning

confidence: 99%

“…When the input to the PCF is the complex excitation signal without the effects of the ultrasound transducers and channel, the output of the matched filter, An analytical solution of the matched filter output, R µµ (τ ), when no transducer or channel is present can be calculated [7] by substituting (1) into (9).…”

Section: Pulse Compression Filter Designmentioning

confidence: 99%

Quinary excitation method for pulse compression ultrasound measurements

Cowell

Freear

2008

Ultrasonics

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A novel switched excitation method for linear frequency modulated excitation of ultrasonic transducers in pulse compression systems is presented that is simple to realise, yet provides reduced signal sidelobes at the output of the matched filter shows improvements in signal to sidelobe noise power in the order of 7 to 8 dB.The reported quinary switched method for linear frequency modulated excitation provides improved performance compared to pesudo chirp excitation without the need for high performance excitation amplifiers.

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Coded excitation for diagnostic ultrasound: a system developer's perspective

Cited by 168 publications

References 19 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

The effect of amplitude modulation on subharmonic imaging with chirp excitation

Quinary excitation method for pulse compression ultrasound measurements

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