Modeling of high-intensity focused ultrasound-induced lesions in the presence of cavitation bubbles

Chavrier, F.; Chapelon, Jean Yves; Gelet, A.; Cathignol, D.

doi:10.1121/1.429476

Cited by 197 publications

(119 citation statements)

References 22 publications

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“…The occurrence of cavitation during HIFU will alter lesion shape, size and position in comparison to purely thermally generated lesions (Chavrier et al 2000;Curiel et al 2004). The role of gas-body generated harmonics versus non-linear propagation in the observations reported here is thus of significance because generation of gas bodies may not be desirable from the standpoint of control of lesion growth.…”

Section: Discussionmentioning

confidence: 75%

“…Experience has shown that bioeffects can be detected when tissue is heated to a level such that gas bodies are formed. The generation of gas bodies during HIFU is known to affect the size, shape and location of lesions relative to the focal point due to their interaction with the therapeutic beam Chavrier et al 2000). During exposure, the acoustic signature of cavitation bubble collapse can be detected directly (Thomas et al 2005).…”

Section: Introductionmentioning

confidence: 99%

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Improved visualization of high-intensity focused ultrasound lesions

Silverman

Muratore

Ketterling

et al. 2006

Ultrasound in Medicine & Biology

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Spectral parameter imaging in both the fundamental and harmonic of backscattered radiofrequency (RF) data was used for immediate visualization of high-intensity focused ultrasound (HIFU) lesion sites. A focused 5-MHz HIFU transducer with a coaxial 9-MHz focused single-element diagnostic transducer was used to create and scan lesions in chicken breast and freshly excised rabbit liver. Bmode images derived from the backscattered RF signal envelope were compared with midband fit (MBF) spectral parameter images in the fundamental (9-MHz) and harmonic (18-MHz) bands of the diagnostic probe. Images of HIFU-induced lesions derived from the MBF to the calibrated spectrum showed improved contrast (~ 3 dB) of tumor margins versus surround compared to images produced from the conventional signal envelope. MBF parameter images produced from the harmonic band showed higher contrast in attenuated structures (core, shadow) compared to either the conventional envelope (3.3 dB core; 11.6 dB shadow) or MBF images of the fundamental band (4.4 dB core; 7.4 dB shadow). The gradient between the lesion and surround was 3.4 dB/mm, 6.9 dB/mm and 17.2 dB/mm for B-mode, MBF-fundamental mode and MBF-harmonic mode respectively. Images of threshold and 'popcorn' lesions produced in freshly excised rabbit liver were most easily visualized and boundaries best defined using MBF-harmonic mode.

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Section: Discussionmentioning

confidence: 75%

Section: Introductionmentioning

confidence: 99%

Improved visualization of high-intensity focused ultrasound lesions

Silverman

Muratore

Ketterling

et al. 2006

Ultrasound in Medicine & Biology

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“…Such activity can be exploited to visualize ablation effects (Sanghvi et al 1995;Rabkin et al 2005Rabkin et al , 2006 or to enhance tissue absorption (Melodelima et al 2001;Sokka et al 2003;Umemura et al 2005;Kaneko et al 2005), but can also complicate ultrasound energy deposition and the resulting spatial pattern of tissue coagulation (Watkin et al 1996;Chen et al 2003;Makin et al 2005;. Mechanisms for interactions between cavitation activity and ultrasound-induced heating have been clarified by several detailed numerical modeling studies (Hilgenfeldt et al 2000;Chavrier et al 2000;Yang et al 2004) and phantom experiments (Holt and Roy 2001;Khokhlova et al 2006). Cavitation activity, measured by passive detection of acoustic emissions, has also been found to correlate with cellular-level bioeffects (Edmonds and Ross 1986;Hallow et al 2006) and with ultrasound enhancement of thrombolysis (Datta et al 2006).…”

Section: Introductionmentioning

confidence: 99%

Acoustic Emissions During 3.1 MHz Ultrasound Bulk Ablation In Vitro

Mast

Salgaonkar

Karunakaran

et al. 2008

Ultrasound in Medicine & Biology

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Acoustic emissions associated with cavitation and other bubble activity have previously been observed during ultrasound ablation experiments. Since detectable bubble activity may be related to temperature, tissue state, and sonication characteristics, these acoustic emissions are potentially useful for monitoring and control of ultrasound ablation. To investigate these relationships, ultrasound ablation experiments were performed with simultaneous measurements of acoustic emissions, tissue echogenicity, and tissue temperature, on fresh bovine liver. Ex vivo tissue was exposed to 0.9-3.3 s bursts of unfocused, continuous-wave, 3.10 MHz ultrasound from a miniaturized 32-element array, which performed B-scan imaging with the same piezoelectric elements during brief quiescent periods. Exposures employed pressure amplitudes of 0.8-1.4 MPa for exposure times of 6-20 min, sufficient to achieve significant thermal coagulation in all cases. Acoustic emissions received by a 1 MHz, unfocused passive cavitation detector, beamformed Aline signals acquired by the array, and tissue temperature detected by a needle thermocouple were sampled 0.3-1.1 times per second. Tissue echogenicity was quantified by the backscattered echo energy from a fixed region of interest within the treated zone. Acoustic emission levels were quantified from the spectra of signals measured by the passive cavitation detector, including subharmonic signal components at 1.55 MHz, broadband signal components within the band 0.3-1.1 MHz, and low-frequency components within the band 10-30 kHz. Tissue ablation rates, defined as the thermally ablated volumes per unit time, were assessed by quantitative analysis of digitally imaged, macroscopic tissue sections. Correlation analysis was performed among the averaged and time-dependent acoustic emissions in each band considered, B-mode tissue echogenicity, tissue temperature, and ablation rate. Ablation rate correlated significantly with broadband and low-frequency emissions, but was uncorrelated with subharmonic emissions. Subharmonic emissions were found to depend strongly on temperature in a nonlinear manner, with significant emissions occurring within different temperature ranges for each sonication amplitude. These results suggest potential roles for passive detection of acoustic emissions in guidance and control of bulk ultrasound ablation treatments.

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“…Even though this section deals with non-thermal mechanisms, UCAs can have an effect on bulk tissue heating (Hilgenfeldt et al, 1998(Hilgenfeldt et al, ,2000Chavrier and Chapelon, 2000;Holt and Roy, 2001;Sokka et al, 2003;Umemura et al, 2005). Typically, there is at least a 2-4 times enhancement of tissue heating by cavitation, or, if the bioeffect were a lesion, the lesion volume was likewise enhanced.…”

Section: Cavitation With Injected Microbubblesmentioning

confidence: 99%

Ultrasound–biophysics mechanisms

O’Brien

2007

Progress in Biophysics and Molecular Biology

586

416

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Ultrasonic biophysics is the study of mechanisms responsible for how ultrasound and biological materials interact. Ultrasound-induced bioeffect or risk studies focus on issues related to the effects of ultrasound on biological materials. On the other hand, when biological materials affect the ultrasonic wave, this can be viewed as the basis for diagnostic ultrasound. Thus, an understanding of the interaction of ultrasound with tissue provides the scientific basis for image production and risk assessment. Relative to the bioeffect or risk studies, that is, the biophysical mechanisms by which ultrasound affects biological materials, ultrasound-induced bioeffects are generally separated into thermal and nonthermal mechanisms. Ultrasonic dosimetry is concerned with the quantitative determination of ultrasonic energy interaction with biological materials. Whenever ultrasonic energy is propagated into an attenuating material such as tissue, the amplitude of the wave decreases with distance. This attenuation is due to either absorption or scattering. Absorption is a mechanism that represents that portion of ultrasonic wave that is converted into heat, and scattering can be thought of as that portion of the wave, which changes direction. Because the medium can absorb energy to produce heat, a temperature rise may occur as long as the rate of heat production is greater than the rate of heat removal. Current interest with thermally mediated ultrasound-induced bioeffects has focused on the thermal isoeffect concept. The non-thermal mechanism that has received the most attention is acoustically generated cavitation wherein ultrasonic energy by cavitation bubbles is concentrated. Acoustic cavitation, in a broad sense, refers to ultrasonically induced bubble activity occurring in a biological material that contains pre-existing gaseous inclusions. Cavitation-related mechanisms include radiation force, microstreaming, shock waves, free radicals, microjets and strain. It is more challenging to deduce the causes of mechanical effects in tissues that do not contain gas bodies. These ultrasonic biophysics mechanisms will be discussed in the context of diagnostic ultrasound exposure risk concerns.

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Modeling of high-intensity focused ultrasound-induced lesions in the presence of cavitation bubbles

Cited by 197 publications

References 22 publications

Improved visualization of high-intensity focused ultrasound lesions

Improved visualization of high-intensity focused ultrasound lesions

Acoustic Emissions During 3.1 MHz Ultrasound Bulk Ablation In Vitro

Ultrasound–biophysics mechanisms

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