Noninvasive bladder volume measurements based on nonlinear wave distortion

Bouakaz, Ayache; Merks, E.J.W.; Lancée, C.T.; Bom, N.

doi:10.1016/j.ultrasmedbio.2003.11.006

Cited by 14 publications

(8 citation statements)

References 20 publications

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“…In the literature this is referred to as superharmonic imaging (SHI). 5,6 Experimental data reveal that attenuation or loss is another phenomenon of substantial importance in medical applications of ultrasound. At ultrasonic frequencies, attenuation in biological tissue is mainly due to absorption, i.e., the irreversible conversion of acoustic energy into heat, and to a lesser extent to scattering of the acoustic energy in arbitrary directions.…”

Section: Introductionmentioning

confidence: 99%

A contrast source method for nonlinear acoustic wave fields in media with spatially inhomogeneous attenuation

Demi

Dongen

Verweij

2011

The Journal of the Acoustical Society of America

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Experimental data reveals that attenuation is an important phenomenon in medical ultrasound. Attenuation is particularly important for medical applications based on nonlinear acoustics, since higher harmonics experience higher attenuation than the fundamental. Here, a method is presented to accurately solve the wave equation for nonlinear acoustic media with spatially inhomogeneous attenuation. Losses are modeled by a spatially dependent compliance relaxation function, which is included in the Westervelt equation. Introduction of absorption in the form of a causal relaxation function automatically results in the appearance of dispersion. The appearance of inhomogeneities implies the presence of a spatially inhomogeneous contrast source in the presented full-wave method leading to inclusion of forward and backward scattering. The contrast source problem is solved iteratively using a Neumann scheme, similar to the iterative nonlinear contrast source (INCS) method. The presented method is directionally independent and capable of dealing with weakly to moderately nonlinear, large scale, three-dimensional wave fields occurring in diagnostic ultrasound. Convergence of the method has been investigated and results for homogeneous, lossy, linear media show full agreement with the exact results. Moreover, the performance of the method is demonstrated through simulations involving steered and unsteered beams in nonlinear media with spatially homogeneous and inhomogeneous attenuation.

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Section: Introductionmentioning

confidence: 99%

A contrast source method for nonlinear acoustic wave fields in media with spatially inhomogeneous attenuation

Demi

Dongen

Verweij

2011

The Journal of the Acoustical Society of America

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“…1,2 Recent studies show that the nonlinear distortion effect may be exploited further by employing the third to the fifth harmonic frequency components 3,4 and by optimizing the ultrasound transducer and the imaging method for the reception of these components. The imaging modality that benefits from the third to the fifth harmonics is called SuperHarmonic Imaging ͑SHI͒.…”

Section: Introductionmentioning

confidence: 99%

An iterative method for the computation of nonlinear, wide-angle, pulsed acoustic fields of medical diagnostic transducers

Huijssen

Verweij

2010

The Journal of the Acoustical Society of America

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The development and optimization of medical ultrasound transducers and imaging modalities require a computational method that accurately predicts the nonlinear acoustic pressure field. A prospective method should provide the wide-angle, pulsed field emitted by an arbitrary planar source distribution and propagating in a three-dimensional, large scale domain holding a nonlinear acoustic medium. In this paper, a method is presented that is free of any assumed wavefield directionality. The nonlinear acoustic wave equation is solved by treating the nonlinear term as a contrast source. This formulation leads to an iterative scheme that involves the repetitive solution of a linear wave problem through Green's function method. It is shown that accurate field predictions may be obtained within a few iterations. Moreover, by employing a dedicated numerical convolution technique, the method allows for a discretization down to two points per wavelength or period of the highest frequency of interest. The performance of the method is evaluated through a number of nonlinear field predictions for pulsed transducers with various geometries. The results demonstrate the directional independence of the method. Moreover, comparison with results from several existing methods shows that the method accurately predicts the nonlinear field for weak to moderate nonlinearity.

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“…Further improvements could also be achieved by optimizing the measurement protocol to account for the bladder volume, which can be adjusted by voiding. An empty bladder could result in increased attenuation from intestinal tissue in the ultrasound path, whereas a full bladder may result in non-linear propagation artifacts because of a long ultrasound propagation pathway through urine (Bouakaz et al 2004). In general, at the adopted higher mechanical index, necessary for proper insonification of the peripheral zone in the prostate, other effects may occur affecting the image quality, such as bubble destruction and non-linear propagation artifacts that can be observed independent of the amount of urine along the ultrasound path.…”

Section: Discussionmentioning

confidence: 99%

Transabdominal Contrast-Enhanced Ultrasound Imaging of the Prostate

Mischi

Demi

Smeenge

et al. 2015

Ultrasound in Medicine & Biology

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Numerous age-related pathologies affect the prostate gland, the most menacing of which is prostate cancer (PCa). The diagnostic tools for prostate investigation are invasive, requiring biopsies when PCa is suspected. Novel dynamic contrast-enhanced ultrasound (DCE-US) imaging approaches have been proposed recently and appear promising for minimally invasive localization of PCa. Ultrasound imaging of the prostate is traditionally performed with a transrectal probe because the location of the prostate allows for high-resolution images using high-frequency transducers. However, DCE-US imaging requires lower frequencies to induce bubble resonance and, thus, improve contrast-to-tissue ratio. For this reason, in this study we investigate the feasibility of quantitative DCE-US imaging of the prostate via the abdomen. The study included 10 patients (age = 60.7 ± 5.7 y) referred for a needle biopsy study. After having given informed consent, patients underwent DCE-US with both transabdominal and transrectal probes. Time-intensity contrast curves were derived using both approaches and their model-fit quality was compared. Although further improvements are expected by optimization of the transabdominal settings, the results of transabdominal and transrectal DCE-US are closely comparable, confirming the feasibility of transabdominal DCE-US; transabdominal curve fitting revealed an average determination coefficient r(2) = 0.91 (r(2) > 0.75 for 78.6% of all prostate pixels) compared with r(2) = 0.91 (r(2) > 0.75 for 81.6% of all prostate pixels) by the transrectal approach. Replacing the transrectal approach with more acceptable transabdominal scanning for prostate investigation is feasible. This approach would improve patient comfort and represent a useful option for PCa localization and monitoring.

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Noninvasive bladder volume measurements based on nonlinear wave distortion

Cited by 14 publications

References 20 publications

A contrast source method for nonlinear acoustic wave fields in media with spatially inhomogeneous attenuation

A contrast source method for nonlinear acoustic wave fields in media with spatially inhomogeneous attenuation

An iterative method for the computation of nonlinear, wide-angle, pulsed acoustic fields of medical diagnostic transducers

Transabdominal Contrast-Enhanced Ultrasound Imaging of the Prostate

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