An update of contrast microbubble phenomena - Archive ouverte HAL Accéder directement au contenu
Communication Dans Un Congrès Année : 2007

An update of contrast microbubble phenomena

Résumé

Ultrasound contrast agents consist of encapsulated bubbles in the micrometer size range. At low acoustic amplitudes these μ-bubbles pulsate linearly, at high amplitudes they demonstrate highly nonlinear, destructive behavior. Cellular drug uptake and lysis are increased under ultrasound insonification, and even more when a contrast agent is present, owing to the formation of transient porosities in the cell membrane (sonoporation). We give an overview of the physical mechanisms of μ-bubble behavior. Microbubble oscillation and translation can be modeled using large encapsulated bubble theory. Contrast μ-bubbles have been observed to coalesce, fragment, crack, buckle, and jet. The number of fragments into which an insonified bubble breaks up has been related to the dominant spherical harmonic oscillation mode and to the energy absorbed by the bubble. Fragmentation thresholds computed for lipid-encapsulated μ-bubbles lie far below Blake's cavitation threshold. There are two hypotheses for explaining the sonoporation phenomenon, the first being bubble oscillations near a cell membrane, the second being bubble jetting through the cell membrane. Based on modeling, photography, and cellular uptake measurements, it is concluded that bubble jetting behavior is less likely to be the dominant sonoporation mechanism. Increasing concern has been shown for ultrasound safety issues when using ultrasound contrast agents. Current acoustic amplitudes allowed are based on tissue without cavitation nuclei present. Since the use of ultrasound contrast agents has become increasingly popular, a new safety standard in ultrasonic imaging will have to be defined in the near future.
Fichier non déposé

Dates et versions

hal-03576241 , version 1 (15-02-2022)

Identifiants

  • HAL Id : hal-03576241 , version 1

Citer

Michiel Postema, Georg Schmitz. An update of contrast microbubble phenomena. International Congess on Ultrasonics (2007ICU), Vienna University of Technology, Apr 2007, Wien, Austria. pp.211-212. ⟨hal-03576241⟩
10 Consultations
0 Téléchargements

Partager

Gmail Facebook X LinkedIn More