scholarly journals Influence of the pressure-dependent resonance frequency on the bifurcation structure and backscattered pressure of ultrasound contrast agents: A numerical investigation

2021 ◽  
Author(s):  
Amin Jafari Sojahrood ◽  
Omar Falou ◽  
Robert Earl ◽  
Raffi Karshafian ◽  
Michael C. Kolios
Keyword(s):  
Contrast Agents ◽  
Cross Section ◽  
Expansion Ratio ◽  
Ultrasound Contrast Agents ◽  
Driving Pressure ◽  
Radial Expansion ◽  
Bifurcation Structure ◽  
Saddle Node Bifurcation ◽  
Ultrasound Contrast ◽  
Ultrasound Applications

The bifurcation structure of the oscillations of ultrasound contrast agents (UCAs) was studied as a function of the driving pressure for excitation frequencies that were determined using the UCAs pressure-dependent resonances (fs)(fs). It was shown that when excited by the (fs)(fs), the UCA can undergo a saddle-node bifurcation (SNB) to higher amplitude oscillations. The driving pressure at which the SNB occurs is controllable and depends on the (fs)(fs) magnitude. Utilizing the appropriate (fs)(fs), the scattering cross section of the UCAs can significantly be enhanced (e.g., ∼∼ninefold) while at the same time avoiding potential UCA destruction (by limiting the radial expansion ratio <<2). This offers significant advantages for optimizing UCA-mediated imaging and therapeutic ultrasound applications.

scholarly journals Influence of the pressure-dependent resonance frequency on the bifurcation structure and backscattered pressure of ultrasound contrast agents: A numerical investigation

2021 ◽  
Author(s):  
Amin Jafari Sojahrood ◽  
Omar Falou ◽  
Robert Earl ◽  
Raffi Karshafian ◽  
Michael C. Kolios
Keyword(s):  
Contrast Agents ◽  
Cross Section ◽  
Expansion Ratio ◽  
Ultrasound Contrast Agents ◽  
Driving Pressure ◽  
Radial Expansion ◽  
Bifurcation Structure ◽  
Saddle Node Bifurcation ◽  
Ultrasound Contrast ◽  
Ultrasound Applications

The bifurcation structure of the oscillations of ultrasound contrast agents (UCAs) was studied as a function of the driving pressure for excitation frequencies that were determined using the UCAs pressure-dependent resonances (fs)(fs). It was shown that when excited by the (fs)(fs), the UCA can undergo a saddle-node bifurcation (SNB) to higher amplitude oscillations. The driving pressure at which the SNB occurs is controllable and depends on the (fs)(fs) magnitude. Utilizing the appropriate (fs)(fs), the scattering cross section of the UCAs can significantly be enhanced (e.g., ∼∼ninefold) while at the same time avoiding potential UCA destruction (by limiting the radial expansion ratio <<2). This offers significant advantages for optimizing UCA-mediated imaging and therapeutic ultrasound applications.

scholarly journals Update on the safety and efficacy of commercial ultrasound contrast agents in cardiac applications

2015 ◽  
Vol 2 (2) ◽  
pp. R55-R62 ◽  
Author(s):  
Andrew W Appis ◽  
Melissa J Tracy ◽  
Steven B Feinstein
Keyword(s):  
Contrast Agents ◽  
Ultrasound Contrast Agents ◽  
Safety And Efficacy ◽  
Off Label ◽  
Ultrasound Contrast ◽  
The Us ◽  
Safety Studies ◽  
Post Marketing ◽  
Marketing Data ◽  
Ultrasound Applications

Ultrasound contrast agents (UCAs) are currently used throughout the world in both clinical and research settings. The concept of contrast-enhanced ultrasound imaging originated in the late 1960s, and the first commercially available agents were initially developed in the 1980s. Today's microbubbles are designed for greater utility and are used for both approved and off-label indications. In October 2007, the US Food and Drug Administration (FDA) imposed additional product label warnings that included serious cardiopulmonary reactions, several new disease-state contraindications, and a mandated 30 min post-procedure monitoring period for the agents Optison and Definity. These additional warnings were prompted by reports of cardiopulmonary reactions that were temporally related but were not clearly attributable to these UCAs. Subsequent published reports over the following months established not only the safety but also the improved efficacy of clinical ultrasound applications with UCAs. The FDA consequently updated the product labeling in June 2008 and reduced contraindications, although it continued to monitor select patients. In addition, a post-marketing program was proposed to the sponsors for a series of safety studies to further assess the risk of UCAs. Then in October 2011, the FDA leadership further downgraded the warnings after hearing the results of the post-marketing data, which revealed continued safety and improved efficacy. The present review focuses on the use of UCAs in today's clinical practice, including the approved indications, a variety of off-label uses, and the most recent data, which affirms the safety and efficacy of UCAs.

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