A finite-element method model of soft tissue response to impulsive acoustic radiation force

• Published in: IEEE transactions on ultrasonics, ferroelectrics, and frequency control Vol. 52; no. 10; pp. 1699 - 1712
• Main Authors: Palmeri, M.L., Sharma, A.C., Bouchard, R.R., Nightingale, R.W., Nightingale, K.R.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.10.2005; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Acoustic arrays; Acoustic imaging; Acoustic measurements; Acoustic radiation; Acoustic transducers; Acoustics; Algorithms; Animals; Biological and medical sciences; Biological tissues; Computer Simulation; Connective Tissue - diagnostic imaging; Connective Tissue - physiology; Dynamic response; Elasticity; Exact sciences and technology; Excitation; Finite Element Analysis; Finite element method; Finite element methods; Fundamental areas of phenomenology (including applications); General equipment and techniques; Humans; Image Enhancement - methods; Image Interpretation, Computer-Assisted - methods; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Investigative techniques, diagnostic techniques (general aspects); Mathematical analysis; Mathematical models; Mechanical factors; Mechanical properties; Mechanical variables measurement; Medical sciences; Miscellaneous. Technology; Models, Biological; Physics; Sonication; Stress, Mechanical; Studies; Transducers; Ultrasonic imaging; Ultrasonic investigative techniques; Ultrasonic Therapy - methods; Ultrasonic variables measurement; Ultrasonics, quantum acoustics, and physical effects of sound; Ultrasonography - methods; Viscosity; Human; Tracking; Acoustic interferometry; Ultrasound imaging; Linear array; Elastic wave; Modeling; Finite element method; Tissue; Linear antenna; Poisson ratio; Pulse response; Radiation force; Acoustic radiation; Tracking(movable target); Medical imagery; Properties of materials; S wave; Soft tissue; Acoustic image; Elastography; Transducer network
• ISSN: 0885-3010; 1525-8955
• DOI: 10.1109/TUFFC.2005.1561624

Several groups are studying acoustic radiation force and its ability to image the mechanical properties of tissue. Acoustic radiation force impulse (ARFI) imaging is one modality using standard diagnostic ultrasound scanners to generate localized, impulsive, acoustic radiation forces in tissue. The dynamic response of tissue is measured via conventional ultrasonic speckle-tracking methods and provides information about the mechanical properties of tissue. A finite-element method (FEM) model has been developed that simulates the dynamic response of tissues, with and without spherical inclusions, to an impulsive acoustic radiation force excitation from a linear array transducer. These FEM models were validated with calibrated phantoms. Shear wave speed, and therefore elasticity, dictates tissue relaxation following ARFI excitation, but Poisson's ratio and density do not significantly alter tissue relaxation rates. Increased acoustic attenuation in tissue increases the relative amount of tissue displacement in the near field compared with the focal depth, but relaxation rates are not altered. Applications of this model include improving image quality, and distilling material and structural information from tissue's dynamic response to ARFI excitation. Future work on these models includes incorporation of viscous material properties and modeling the ultrasonic tracking of displaced scatterers.