Study of ultrasonic contrast agents using a dual-frequency band technique

Deng, Cheri X.; Lizzi, Frederic L.; Kalisz, Andrew; Rosado, A.; Silverman, Ronald H.; Coleman, D. Jackson

doi:10.1016/s0301-5629(00)00217-9

Cited by 44 publications

(32 citation statements)

References 16 publications

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“…Upon excitation by multifrequency bursts, MBs can also act as non-linear mixers of the excitation frequencies and produce cross-products [98][99][100]. Conventional non-linear imaging techniques, at lower frequencies (515 MHz), focus mainly on detection of higher harmonics [101][102][103][104][105].…”

Section: Contrast-specific Imaging Techniquesmentioning

confidence: 99%

Targeted ultrasound contrast agents for ultrasound molecular imaging and therapy

Rooij

Daeichin

Skachkov

et al. 2015

International Journal of Hyperthermia

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Ultrasound contrast agents (UCAs) are used routinely in the clinic to enhance contrast in ultrasonography. More recently, UCAs have been functionalised by conjugating ligands to their surface to target specific biomarkers of a disease or a disease process. These targeted UCAs (tUCAs) are used for a wide range of pre-clinical applications including diagnosis, monitoring of drug treatment, and therapy. In this review, recent achievements with tUCAs in the field of molecular imaging, evaluation of therapy, drug delivery, and therapeutic applications are discussed. We present the different coating materials and aspects that have to be considered when manufacturing tUCAs. Next to tUCA design and the choice of ligands for specific biomarkers, additional techniques are discussed that are applied to improve binding of the tUCAs to their target and to quantify the strength of this bond. As imaging techniques rely on the specific behaviour of tUCAs in an ultrasound field, it is crucial to understand the characteristics of both free and adhered tUCAs. To image and quantify the adhered tUCAs, the state-of-the-art techniques used for ultrasound molecular imaging and quantification are presented. This review concludes with the potential of tUCAs for drug delivery and therapeutic applications.

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Section: Contrast-specific Imaging Techniquesmentioning

confidence: 99%

Targeted ultrasound contrast agents for ultrasound molecular imaging and therapy

Rooij

Daeichin

Skachkov

et al. 2015

International Journal of Hyperthermia

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“…In a first approach, freely floating bubbles were excited at frequencies around their resonance and imaged using higher frequencies [15], [16]. More recently, single bubbles in an acoustically and optically transparent tube have been observed.…”

mentioning

confidence: 99%

Method for Microbubble Characterization Using Primary Radiation Force

Vos

Guidi

Boni

et al. 2007

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

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Medical ultrasound contrast agents (UCAs) have evolved from straight image enhancers to pathophysiological markers and drug delivery vehicles. However, the exact dynamic behavior of the encapsulated bubbles composing UCAs is still not entirely known. In this article, we propose to characterize full populations of UCAs, by looking at the translational effects of ultrasound radiation force on each bubble in a diluted population. The setup involves a sensitive, fully programmable transmitter/receiver and two unconventional, real-time display modes. Such display modes are used to measure the displacements produced by irradiation at frequencies in the range 2-8 MHz and pressures between 150 kPa and 1. MPa. The behavior of individual bubbles freely moving in a water tank is clearly observed, and it is shown that it depends on the bubble physical dimensions as well as on the viscoelastic properties of the encapsulation. A new method also is distilled that estimates the viscoelastic properties of bubble encapsulation by fitting the experimental bubble velocities to values simulated by a numerical model based on the modifiedHerring equation and the Bjerknes force. The fit results are a shear modulus of 18 MPa and a viscosity of 0.23 Pas for a thermoplastic PVC-AN shell. Phospholipid shell elasticity and friction parameter of the experimental contrast agent are estimated as 0.8 N/m and 1 10 ;7 kg/s, respectively (shear modulus of 32 MPa and viscosity of 0.19 Pas, assuming 4-nm shell thickness).

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“…RMI is based on the assumption that there is a variation of the bubble's response to the imaging pulse depending on its oscillatory state at the time of reception of this pulse. A difference in the backscattered signal was indeed observed experimentally at 10 MHz between the compression and expansion phase of the bubbles induced by a 0.5 MHz ultrasound excitation by Deng et al [6]. Therefore, echoes obtained at the imaging frequency at two different phases of bubble's oscillation should not cancel out by subtraction, as opposed to echoes from the surrounding tissues, in which scatterers are not affected by the modulation pulse.…”

Section: Introductionmentioning

confidence: 84%

10C-3 Radial Modulation Imaging of Microbubbles at High Frequency

Chérin

Brown

Shariff

et al. 2007

2007 IEEE Ultrasonics Symposium Proceedings

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In this paper, radial modulation imaging of microbubbles is investigated at high frequency. A modulation pulse frequency of 3.7 MHz with an amplitude ranging from 0 to 250 kPa, and a 1.3 MPa 20 MHz broadband imaging pulse were used. Radial modulation effects were observed on a population of flowing microbubbles and quantified using a Doppler-type processing technique. Artifact signals related to the generation of harmonics by bubbles strongly resonating at the modulation frequency were observed. The bubble response to simultaneous modulation and imaging excitations was simulated for different combinations of bubble sizes and modulation amplitudes. Simulations confirm the hypothesis that the generation of harmonics of the modulation frequency can be detected by the imaging transducer. Simulations indicate that the modulation frequency should be chosen lower than the resonant frequency of the biggest bubbles present in the population. The simulation also suggests that a 10-20% variation of bubble diameter induced by the modulation excitation is sufficient for radial modulation imaging. In conclusion, the effects of radial modulation are detectable at a high frequency. Therefore, radial modulation imaging has potential for high-resolution imaging of microbubbles in the microvasculature.

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Study of ultrasonic contrast agents using a dual-frequency band technique

Cited by 44 publications

References 16 publications

Targeted ultrasound contrast agents for ultrasound molecular imaging and therapy

Targeted ultrasound contrast agents for ultrasound molecular imaging and therapy

Method for Microbubble Characterization Using Primary Radiation Force

10C-3 Radial Modulation Imaging of Microbubbles at High Frequency

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