Nonlinear wave propagation - a fast 3D simulation method based on quasi-linear approximation of the second harmonic field

The Journal of the Acoustical Society of America

Holm

et al. 2012

Nonlinear propagation of sound has been exploited in the last 15 years in medical ultrasound imaging through tissue harmonic imaging (THI). THI creates an image by filtering the received ultrasound echo around the second harmonic frequency band. This technique produces images of enhanced quality due to reduced body wall reverberation, lower perturbations from off-axis echoes, and multiple scattering of reduced amplitude. In order to optimize the image quality it is essential to be able to predict the amplitude level and spatial distribution of the propagating ultrasound pulse. A method based on the quasi-linear approximation has been developed to quickly provide an estimate of the ultrasound pulse. This method does not need to propagate the pulse stepwise from the source plane to the desired depth; it directly computes a transverse profile at any depth from the definitions of the transducer and the pulse. The computation handles three spatial dimensions which allows for any transducer geometry. A comparison of pulse forms, transverse profiles, as well as axial profiles obtained by this method and state-of-the-art simulators, the KZKTexas code, and Abersim, shows a satisfactory match. The computation time for the quasi-linear method is also smaller than the time required by the other methods.

Section: Introductionmentioning

confidence: 99%

Fast simulation of second harmonic ultrasound field using a quasi-linear method

Prieur

The Journal of the Acoustical Society of America

Holm

et al. 2012

“…For a more detailed description of the quasilinear simulation method, the reader is referred to [1].…”

Section: Theorymentioning

confidence: 99%

“…This may be exploited to introduce a quasilinear approximation of the wave propagation [1]. Presented here is a validation of this quasilinear simulation approach.…”

Section: Introductionmentioning

confidence: 99%

Influence of acoustic intensity on the second-harmonic beam-profile

Varslot

Dursun

IEEE Symposium on Ultrasonics, 2003

et al.

Self Cite

A method for fast numerical simulation of nonlinear wave propagation based on a quasilinear approximation, has previously been presented [1]. The aim of the current study was to validate this method by comparing the simulation results to the results from a conventional simulation model, and to experimental measurements. The reference simulation model was based on solving the KZK-equation using an operator splitting approach. Experimental measurements were obtained in a water tank. An annular array probe was used to generate a focused transmit pulse. Hydrophone measurements of the ultrasonic field were used for experimental verification of the simulation. Beam-profiles from the two simulation methods and the hydrophone measurements were compared for pulses with a mechanical index (MI) ranging from 0.1 to 1.9. The results showed an almost perfect match between the two simulation models for MI less than 0.5. For higher MI values, the KZK-based method showed a gradual increase in the side-lobe level, whereas the main-lobe width and shape were preserved. These effects were also demonstrated by the hydrophone measurements.

“…A method based on the quasi-linear approximation has previously been presented [6]. It is a method where the second harmonic field is calculated using the first harmonic field as a source.…”

Section: Introductionmentioning

confidence: 99%

Fast 3D simulation of 2nd harmonic ultrasound field from arbitrary transducer geometries

Dursun

Varslot

IEEE Ultrasonics Symposium, 2005.

et al.

Self Cite

A method for fast numerical simulation of nonlinear wave propagation based on a quasi-linear approximation has previously been presented. In the current study this method has been further developed to yield correct levels of the secondharmonic wave. The method can be used for 3D simulations of second-harmonic fields from arbitrarily transducer geometries. The method has been validated by comparing simulations to results produced by a conventional nonlinear simulation model and to experimental measurements. The reference simulation model was a numerical solution of the KZK equation for a forward-propagating pulse using a operator splitting approach. Experimental verifications were performed with hydrophone measurements in a water tank. Results showed a good match between the simulation models and measurements for MI up to 0.4 for an annular array probe and for MI up to 1 for a rectangular probe. For higher MI values the quasi-linear method showed a gradual increased over-estimation of the second harmonic field.