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Nonlinear ultrasound propagation through layered liquid and tissue-equivalent media: Computational and experimental results at high frequency

Williams, R ; Sharif University of Technology | 2006

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  1. Type of Document: Article
  2. DOI: 10.1088/0031-9155/51/22/006
  3. Publisher: 2006
  4. Abstract:
  5. Nonlinear propagation has been demonstrated to have a significant impact on ultrasound imaging. An efficient computational algorithm is presented to simulate nonlinear ultrasound propagation through layered liquid and tissue-equivalent media. Results are compared with hydrophone measurements. This study was undertaken to investigate the role of nonlinear propagation in high frequency ultrasound micro-imaging. The acoustic field of a focused transducer (20 MHz centre frequency, f-number 2.5) was simulated for layered media consisting of water and tissue-mimicking phantom, for several wide-bandwidth source pulses. The simulation model accounted for the effects of diffraction, attenuation and nonlinearity, with transmission and refraction at layer boundaries. The parameter of nonlinearity, B/A, of the water and tissue-mimicking phantom were assumed to be 5.2 and 7.4, respectively. The experimentally measured phantom B/A value found using a finite-amplitude insert-substitution method was shown to be 7.4 ± 0.6. Relative amounts of measured second and third harmonic pressures as a function of the fundamental pressures at the focus were in good agreement with simulations. Agreement within 3% was found between measurements and simulations of the beam widths of the fundamental and second harmonic signals following propagation through the tissue phantom. The results demonstrate significant nonlinear propagation effects for high frequency imaging beams. © 2006 IOP Publishing Ltd
  6. Keywords:
  7. Acoustic fields ; Computational methods ; Hydrophones ; Natural frequencies ; Tissue ; Ultrasonic transducers ; Layered liquids ; Nonlinear propagation ; Phantoms ; Ultrasound imaging ; Ultrasonic propagation ; Acoustics ; Analytic method ; Biomicroscopy ; Diffraction ; Mathematical computing ; Mathematical model ; Nonlinear system ; Priority journal ; Radiation attenuation ; Transducer ; Ultrasound ; Computer Simulation ; Image Interpretation, Computer-Assisted ; Models, Biological ; Phantoms, Imaging ; Radiation Dosage ; Radiometry ; Scattering, Radiation ; Ultrasonics ; Ultrasonography
  8. Source: Physics in Medicine and Biology ; Volume 51, Issue 22 , 2006 , Pages 5809-5824 ; 00319155 (ISSN)
  9. URL: https://iopscience.iop.org/article/10.1088/0031-9155/51/22/006