Finite-element modeling of microsphere surface modes and high-frequency ultrasound scattering from a single cell

2007 ◽  
Vol 122 (5) ◽  
pp. 2957
Author(s):  
Omar Falou ◽  
J. Carl Kumaradas ◽  
Michael C. Kolios
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Single Cell ◽  
High Frequency ◽  
High Frequency Ultrasound ◽  
Surface Modes ◽  
Element Modeling ◽  
Ultrasound Scattering ◽  
Frequency Ultrasound

scholarly journals Modelling high frequency ultrasound scattering from cells and ultrasound contrast agents

2021 ◽  
Author(s):  
Omar Falou
Keyword(s):  
Contrast Agents ◽  
High Frequency ◽  
Ultrasound Contrast Agents ◽  
Polystyrene Microspheres ◽  
High Frequency Ultrasound ◽  
Surface Modes ◽  
Ultrasound Contrast ◽  
Resonance Frequencies ◽  
Ultrasound Scattering ◽  
Frequency Ultrasound

High frequency ultrasound has been shown to detect structural and physical changes in cell ensembles during apoptosis and hence has the potential of monitoring cancer treatment. Ultrasound contrast agents have also been shown to enhance contrast between blood and the surrounding tissue and hence may be used to distinguish between treated and untreated tumours. Theoretical models of high frequency ultrasound scattering from individual cells and ultrasound contrast agents (UCAs) are needed in order to develop methods for using high frequency ultrasound to classify tumours, quantify their responses to treatment, and eventually provide a better cancer detection and treatment monitoring techniques. This work introduces a new technique for measuring the ultrasound backscatter from individual micron-sized objects by combining a microinjection system with a co-registered optical microscope and an ultrasound imaging device. The system was calibrated by measuring the backscatter response from polystyrene microspheres and comparing it to theoretical predictions of an elastic sphere. The backscatter responses from single sea urchin oocytes and acute myloid leukemia cells were also investigated. It was found that such responses are best modelled using the fluid sphere model. A finite element model was also introduced to study scattering from microspheres and UCAs. The Helmholtz equation was used to describe the propagation of sound waves in the fluid domains whereas the constitutive equation was used to describe the stress-strain relationship in the solid domains. Studies on polystyrene microspheres and UCAs revealed the existence of a systematic relationship between the resonance frequencies and the microsphere surface modes. No such a relationship was found for the UCAs of interest. Instead, these agents exhibited a collection of complex oscillations which appear to be a combination of various surface modes. Increasing the UCA's shell thickness and its shear modulus produced a shift in the resonance frequencies to higher values. A decrease in UCA diameter produced similar effects. The importance of these findings towards the understanding of the UCA behaviour at high frequencies and the generation of harmonics are discussed. Future work includes the measurement of the backscatter response from individual UCAs and cells at various apoptotic stages.

scholarly journals Modelling high frequency ultrasound scattering from cells and ultrasound contrast agents

2021 ◽  
Author(s):  
Omar Falou
Keyword(s):  
Contrast Agents ◽  
High Frequency ◽  
Ultrasound Contrast Agents ◽  
Polystyrene Microspheres ◽  
High Frequency Ultrasound ◽  
Surface Modes ◽  
Ultrasound Contrast ◽  
Resonance Frequencies ◽  
Ultrasound Scattering ◽  
Frequency Ultrasound

High frequency ultrasound has been shown to detect structural and physical changes in cell ensembles during apoptosis and hence has the potential of monitoring cancer treatment. Ultrasound contrast agents have also been shown to enhance contrast between blood and the surrounding tissue and hence may be used to distinguish between treated and untreated tumours. Theoretical models of high frequency ultrasound scattering from individual cells and ultrasound contrast agents (UCAs) are needed in order to develop methods for using high frequency ultrasound to classify tumours, quantify their responses to treatment, and eventually provide a better cancer detection and treatment monitoring techniques. This work introduces a new technique for measuring the ultrasound backscatter from individual micron-sized objects by combining a microinjection system with a co-registered optical microscope and an ultrasound imaging device. The system was calibrated by measuring the backscatter response from polystyrene microspheres and comparing it to theoretical predictions of an elastic sphere. The backscatter responses from single sea urchin oocytes and acute myloid leukemia cells were also investigated. It was found that such responses are best modelled using the fluid sphere model. A finite element model was also introduced to study scattering from microspheres and UCAs. The Helmholtz equation was used to describe the propagation of sound waves in the fluid domains whereas the constitutive equation was used to describe the stress-strain relationship in the solid domains. Studies on polystyrene microspheres and UCAs revealed the existence of a systematic relationship between the resonance frequencies and the microsphere surface modes. No such a relationship was found for the UCAs of interest. Instead, these agents exhibited a collection of complex oscillations which appear to be a combination of various surface modes. Increasing the UCA's shell thickness and its shear modulus produced a shift in the resonance frequencies to higher values. A decrease in UCA diameter produced similar effects. The importance of these findings towards the understanding of the UCA behaviour at high frequencies and the generation of harmonics are discussed. Future work includes the measurement of the backscatter response from individual UCAs and cells at various apoptotic stages.

scholarly journals A human skin ultrasonic imaging to analyse its mechanical properties

2009 ◽  
pp. 105-116
Author(s):  
Alexandre Delalleau ◽  
Gwendal Josse ◽  
Jérôme George ◽  
Yassine Mofid ◽  
Frédéric Ossant ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
High Frequency ◽  
Complex Structure ◽  
Mechanical Parameters ◽  
High Frequency Ultrasound ◽  
Specific Procedure ◽  
Complex Behaviour ◽  
Behaviour Law ◽  
Frequency Ultrasound

The analysis of the skin mechanical behaviour is a key-point for different field of investigation. As the skin is a complex structure, studies are usually based on inverse methods that compare experimental and finite element numerical results. Besides the considered behaviour law, one of the most important question concerns the geometrical aspects of the skin tissue. In this paper, it is shown how high frequency ultrasound imaging helps the calculation of skin mechanical parameters. The hypodermis influence is firstly discussed through elastographic analyses. A specific procedure to measure the dermis thickness is then proposed to highlight that such a measurement must be considered to draw reliable conclusions. The obtained results are finally discussed to point out the interest of such simplifications for the study of more complex behaviour laws.

scholarly journals High-frequency Ultrasound Scattering from Microspheres and Single Cells

2021 ◽  
Author(s):  
Ralph E. Baddour ◽  
Michael D. Sherar ◽  
J. W. Hunt ◽  
G. J. Czarnota ◽  
Michael C. Kolios
Keyword(s):  
High Frequency ◽  
Single Cells ◽  
High Frequency Ultrasound ◽  
Ultrasound Scattering ◽  
Frequency Ultrasound

High-frequency Ultrasound Scattering from Microspheres and Single Cells

scholarly journals Finite-Element Modeling of Viscoelastic Cells During High-Frequency Cyclic Strain

2012 ◽  
Vol 3 (1) ◽  
pp. 209-224 ◽  
Author(s):  
Jaques S. Milner ◽  
Matthew W. Grol ◽  
Kim L. Beaucage ◽  
S. Jeffrey Dixon ◽  
David W. Holdsworth
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
High Frequency ◽  
Cyclic Strain ◽  
Element Modeling

scholarly journals High-frequency ultrasound scattering from microspheres and single cells

2005 ◽  
Vol 117 (2) ◽  
pp. 934-943 ◽  
Author(s):  
R. E. Baddour ◽  
M. D. Sherar ◽  
J. W. Hunt ◽  
G. J. Czarnota ◽  
M. C. Kolios
Keyword(s):  
High Frequency ◽  
Single Cells ◽  
High Frequency Ultrasound ◽  
Ultrasound Scattering ◽  
Frequency Ultrasound
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