Background—Ultrasound can cause microbubble destruction. If microbubbles are administered as a continuous infusion, then their destruction within the myocardium and measurement of their myocardial ...

Quantification of Myocardial Blood Flow With Ultrasound-Induced Destruction of Microbubbles Administered as a Constant Venous Infusion

Microbubbles in ultrasound-triggered drug and gene delivery

Single-bubble sonoluminescence occurs when an acoustically trapped and periodically driven gas bubble collapses so strongly that the energy focusing at collapse leads to light emission. Detailed experiments have demonstrated the unique properties of this system: the spectrum of the emitted light tends to peak in the ultraviolet and depends strongly on the type of gas dissolved in the liquid; small amounts of trace noble gases or other impurities can dramatically change the amount of light emission, which is also affected by small changes in other operating parameters (mainly forcing pressure, dissolved gas concentration, and liquid temperature). This article reviews experimental and theoretical efforts to understand this phenomenon. The currently available information favors a description of sonoluminescence caused by adiabatic heating of the bubble at collapse, leading to partial ionization of the gas inside the bubble and to thermal emission such as bremsstrahlung. After a brief historical review, the authors survey the major areas of research: Section II describes the classical theory of bubble dynamics, as developed by Rayleigh, Plesset, Prosperetti, and others, while Sec. III describes research on the gas dynamics inside the bubble. Shock waves inside the bubble do not seem to play a prominent role in the process. Section IV discusses the hydrodynamic and chemical stability of the bubble. Stable single-bubble sonoluminescence requires that the bubble be shape stable and diffusively stable, and, together with an energy focusing condition, this fixes the parameter space where light emission occurs. Section V describes experiments and models addressing the origin of the light emission. The final section presents an overview of what is known, and outlines some directions for future research.

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Single bubble sonoluminescence

Not all bubbles in the bloodstream are detrimental. During the past decade, contrast-enhanced ultrasound has evolved from a purely investigational tool to a routine diagnostic technique. This transformation has been facilitated by advances in the microbubble contrast agents and contrast-specific ultrasound imaging techniques. The ability to non-invasively image molecular events with targeted microbubbles is likely to be important for characterizing pathophysiology and for developing new therapeutic strategies in the treatment of cardiovascular and neoplastic diseases.

Microbubbles in medical imaging: current applications and future directions.

We present a model applicable to ultrasound contrast agent bubbles that takes into account the physical properties of a lipid monolayer coating on a gas microbubble Three parameters describe the properties of the shell: a buckling radius, the compressibility of the shell, and a break-up shell tension The model presents an original non-linear behavior at large amplitude oscillations, termed compression-only, induced by the buckling of the lipid monolayer This prediction is validated by experimental recordings with the high-speed camera Brandaris 128, operated at several millions of frames per second The effect of aging, or the resultant of repeated acoustic pressure pulses on bubbles, is predicted by the model It corrects a flaw in the shell elasticity term previously used in the dynamical equation for coated bubbles The break-up is modeled by a critical shell tension above which gas is directly exposed to water

N. de Jong

Papers

Absorption and scatter of encapsulated gas filled microspheres: Theoretical considerations and some measurements

Higher harmonics of vibrating gas-filled microspheres. Part one: simulations

Ultrasound scattering properties of Albunex microspheres.

Higher harmonics of vibrating gas-filled microspheres. Part two: measurements

On the effect of lung filtering and cardiac pressure on the standard properties of ultrasound contrast agent.