A unified approach to modeling the backscattered Doppler ultrasound from blood

Mo, L.Y.L.; Cobbold, R.S.C.

doi:10.1109/10.135539

Cited by 119 publications

(66 citation statements)

References 33 publications

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“…Therefore, ultrasound scattering mainly results from the mismatches in the mechanical properties of continuous and particle phases. Theoretical models of ultrasound scattering are based either on the continuum approach [23,24] or the particle approach [12,13,22]. The continuum approach recognizes that particles separated by less than λ/2 cannot be resolved by the transducer and therefore the suspension can be modeled as a continuum medium in which local fluctuations in density and compressibility give rise to the scattered waves [23].…”

Section: Ultrasonic Scattering From a Suspensionmentioning

confidence: 99%

“…In the concentrated regime, particles or clusters can no longer be considered as independent and correlation effects influence the scattered power because of wavelets interference arising from a dense distribution of scatterers [10]. The scattered power can be considered as the result of imperfect wave destruction either associated with a packing factor [12,22] or with the variance in local scatterer concentration [23,24].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Ultrasound and light scattering from a suspension of reversible fractal clusters in shear flow

Snabre

Haider²,

Boynard³

2000

The European Physical Journal E - Soft Matter

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Shear break-up of reversible fractal clusters is investigated by ultrasound and multiple light scattering in the low shear regime. We consider a dense suspension of Rayleigh scatterers (particles or clusters) with acoustic properties close to those of the surrounding liquid so that the attenuation of the ultrasonic coherent field is weak and multiple scattering is negligible. The concept of variance in local particle volume fraction is used to derive an original expression of the ultrasound scattering cross-section per unit volume for Rayleigh fractal clusters. On the basis of a scaling law for the shear break-up of aggregates, then we derive the shear stress dependence of the ultrasound scattered intensity from a suspension of reversible fractal clusters. In a second part, we present rheo-acoustical experiments to study the shear breakup of hardened red cell aggregates in plane-plane flow geometry and we examine both the self consistent field approximation and the scaling laws used in microrheological models. We further compare the ability of acoustical backscattering and optical reflectometry techniques to estimate the critical disaggregation shear stress and the particle surface adhesive energy. Finally, the microrheological model from Snabre and Mills [5] based on a fractal approach is shown to describe the non Newtonian behavior of a dense distribution of hardened red cell aggregates. PACS. 42.25.Fx Diffraction and scattering -43.35.+d Ultrasonics, quantum acoustics, and physical effects of sound -43.80.+p Bioacoustics Nomenclature ν frequency (Hz), λ wavelength (m), a particle radius (m), R cluster radius (m), R maximum size of filling space subclusters at rest (m), δz axial resolution of the transducer (m), h gap width between rotating plates (m), z distance between the transducer and the insonified region (m), V particle volume (m 3 ), V a cluster volume (m 3 ), Ω volume of an elemental voxel (m 3 ), n particle number per unit volume (m −3 ), n a cluster number per unit volume (m −3 ), k, s incident and scattered wave number (m −1 ), q scattering wave number (q = s − k) (m −1 ), B cross-sectional area of the ultrasound beam (m 2 ), A c contact area between two particles (m 2 ), A particle area (m 2 ), a e-mail: snabre@imp-odeillo.fr b UPR 8521 du CNRS c phase velocity of the ultrasound wave (m/s), δtpulsewidth (s), ω particle number in a voxel, N particle number in a cluster, N b number of subunits of size 1/q in a cluster, D fractal dimension of a cluster, φ particle volume fraction, φ a cluster volume fraction, φ * maximum packing volume fraction, φ g gelation or percolation threshold, m critical exponent for cluster breakup, γ shear rate (s −1 ), τ shear stress (N/m 2 ), τ c critical disaggregation shear stress (N/m 2 ), τ * critical shear stress for cluster breakup (N/m 2 ), τ o yield stress (N/m 2 ), µ, µ a shear viscosity of the suspension (Ns/m 2 ), µ o shear viscosity of the suspending fluid (Ns/m 2 ), µ r relative shear viscosity of the suspension (µ r = µ a /µ o ), σ, σ α differential scattering...

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Section: Ultrasonic Scattering From a Suspensionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Ultrasound and light scattering from a suspension of reversible fractal clusters in shear flow

Snabre

Haider²,

Boynard³

2000

The European Physical Journal E - Soft Matter

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“…The rationale for the phenomenon has been well analyzed and explained by the theoretical models (Lucas and Twersky, 1987;Mo and Cobbold, 1992;Bascom and Cobbold, 1995), which show that the scattering from a packed distribution of small scatterers is related to fluctuation of the number and size of the scatterers in a volume rather than the number itself. Experimental reports from RBC suspension by Cloutier et al (1995Cloutier et al ( , 1996Cloutier et al ( , 2000 showed that flow turbulence downstream from a stenosis resulted in increased Doppler power.…”

Section: Review Papermentioning

confidence: 99%

“…A nonlinear relationship between hematocrit and ultrasonic backscatter of RBC suspension was experimentally found and the results were in excellent agreement with the theoretical models which predict a scattering maximum peak at 13-20 % hematocrit (Shung et al 1976;Shung 1988a, 1988b). Later, the packing theory was extended to the continuum model and the particle and continuum models were unified as a hybrid model (Mo and Cobbold, 1992). According to the theory, it was postulated that ultrasound backscatter should be sensitive even to a small degree of RBC aggregation.…”

Section: Scattering Of Ultrasound By Bloodmentioning

confidence: 99%

Ultrasonic visualization of dynamic behavior of red blood cells in flowing blood

Paeng

Nam

2009

J Vis

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It is well known that the scatter of ultrasound by blood is mainly attributed to red blood cells (RBCs) and RBC aggregation. In the present review, researches of hemodynamic influence on RBC aggregation and ultrasound backscatter from blood were overviewed. A mock flow loop and a cylindrical chamber were employed to produce various blood flows, such as pulsatile, oscillatory, and rotational flow. The "black hole" (BLH), a dark hole at the tube center surrounded by bright zone in the cross sectional B-mode image and "bright collapsing ring" (BRCR) phenomena, appearance of bright ring at the periphery and collapse of it at the center during a pulsatile cycle, were observed under pulsatile flow. The combined effects of shear rate and flow acceleration on RBC aggregation were suggested as a possible mechanism for these phenomena. The stroke volume-dependence of the "bright ring" phenomenon under oscillatory flow could also be explained by flow acceleration. The enveloped echo images from rotational flow in a compact blood chamber showed the spatial and temporal variations of RBC aggregation, which varied with the mammalian species. In the stenotic model, it was found that the echogenic variation increased locally at a distance of three tube diameters downstream from the stenosis during decelerating period, which was proposed to be mainly due to flow turbulence. The similar 'bright ring' was also observed from in vivo human carotid artery in harmonic imaging.

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“…However, although the simulations/models of Doppler signals from blood have been developed over many years and have characteristics very similar to real signals [4][5][6][7][8][9][10][11] wall signal models are relatively crude -single sinusoids or random signals. A simulator is required that generates a Doppler signal as from blood and vessel wall, having controllable characteristics similar to those found in practice.…”

Section: Introductionmentioning

confidence: 99%

Blood and wall signal simulator for Doppler ultrasound signal analysis algorithm development

Fish

Bastos²,

Vaz³

2001 Conference Proceedings of the 23rd Annual International Conference of the IEEE Engineering in Medicine and Biology Society

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Abstract-Doppler ultrasound instruments, used for the detection and monitoring of vascular disease, require a means of separating the large, low frequency Doppler signal from the vessel wall from the signal arising from blood followed by a means of analysing the blood flow signal in order to characterise the flow conditions. This is normally achieved by using a high-pass filter that removes the signal reflected from the vessel wall. Unfortunately, the filter also removes the low frequency Doppler signals arising from slow moving blood. A better signal segmentation method that reduces the loss of signal from slowly moving blood is needed to permit the measurement of lower blood velocities. A signal simulator that generates Doppler signals that include the contributions from blood and vessel wall will be very useful for the development of new Doppler signal segmentation methods. This work presents a new simulator incorporating the contribution of blood and vessel wall movements; the characteristics of the simulator output signal are similar to those found in practice.

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A unified approach to modeling the backscattered Doppler ultrasound from blood

Cited by 119 publications

References 33 publications

Ultrasound and light scattering from a suspension of reversible fractal clusters in shear flow

Ultrasound and light scattering from a suspension of reversible fractal clusters in shear flow

Ultrasonic visualization of dynamic behavior of red blood cells in flowing blood

Blood and wall signal simulator for Doppler ultrasound signal analysis algorithm development

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