Numerical Investigation of the Effect of Lipid Shell Shedding Phenomenon of Ultrasound Contrast Agent Microbubbles on their Frequency Response

Document Type : Original Article

Authors

1 Master's student، Shahid Rajaee Teacher Training University

2 associate professor,، Shahid Rajaee Teacher Training University

Abstract

Ultrasound contrast agents or UCAs are microbubbles with a biocompatible shell that increase the resolution of the ultrasound image when injected into the blood. Lipid shedding in UCAs refers to the process of lipid separation from the microbubble shell under ultrasound field stimulation. In this paper, it is shown by dimensional analysis that diffusion phenomena are negligible on the time scales that characterize a typical ultrasonic pulse. Then, using MATLAB software, a modified Rayleigh Plesset equation was solved numerically, which describes both the mechanism of lipid loss and the characteristics of the lipid shell. The results shows that the microbubbles eventually reach a constant equilibrium radius due to shell shedding after successive excitation pulses and this phenomenon causes a significant decrease in the intensity of the frequency response components emitted from them. Also, by increasing the excitation frequency, in the same pressure amplitude , the rate of shell shedding decreases.

Keywords


Volume 13, Issue 2 - Serial Number 33
Autumn and winter 2024
November 2024
  • Receive Date: 29 June 2024
  • Revise Date: 29 September 2024
  • Accept Date: 05 November 2024
  • Publish Date: 21 November 2024