Ultrasound backscatter at 30 MHz from human blood: Influence of rouleau size affected by blood modification and shear rate

Heiden, Maurits S. van der; Kroon, M.G.M. de; Bom, N.; Borst, Cornelius

doi:10.1016/0301-5629(95)00012-g

Cited by 66 publications

(27 citation statements)

References 24 publications

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“…Flow disturbances and turbulence effects may further increase local fluctuations in particle concentration and enhance the ultrasound backscattered power. However, no shear rate dependence was observed below 200 s −1 for the ultrasound power scattered from non-aggregated red cells suspensions in agreement with recent experiments from van der Heiden et al [42].…”

Section: Experimental Protocolsupporting

confidence: 91%

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: Experimental Protocolsupporting

confidence: 91%

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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“…First, the investigators' calculation of the frequency dependence of the backscatter coefficient relied on measurements that exhibited large standard deviations at only two frequencies. Second, frequency-dependent attenuation of the backscatter signal may have also contributed to the variance from the "usual" fourth power relationship between frequency and backscatter intensity observed in Rayleigh scattering (14,28,42). The experiments of Kuo and Shung (25) show that stirred erythrocyte suspensions at hematocrit of 0.06 exhibited Rayleigh scattering, although these were nonaggregating suspensions in saline.…”

Section: Resultsmentioning

confidence: 99%

“…Moreover, an ultrasound frequency of 40 MHz corresponds to a wavelength of ϳ33 m compared with erythrocyte diameters of ϳ15 m (38); thus erythrocytes would not act as scatterers, but rather as reflectors, and the fourth power-frequency relationship of the backscatter intensity would no longer hold. In fact, this relationship, or the "spectral slope," is likely to be underestimated because of such factors (42). Indeed, Lockwood et al (28) showed that at frequencies Ͼ35 MHz, "Rayleigh scattering in blood cannot be expected," finding a frequency-backscatter intensity relationship proportional to the 1.3-1.4 power.…”

Section: Resultsmentioning

confidence: 99%

Spatial velocity profile in mouse embryonic aorta and Doppler-derived volumetric flow: a preliminary model

Phoon¹,

Aristizábal²,

Turnbull

2002

American Journal of Physiology-Heart and Circulatory Physiology

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Phoon, Colin K. L., Orlando Aristizá bal, and Daniel H. Turnbull. Spatial velocity profile in mouse embryonic aorta and Doppler-derived volumetric flow: a preliminary model. Am J Physiol Heart Circ Physiol 283: H908-H916, 2002. First published May 16, 2002 10.1152/ajpheart.00869.2001.-Characterizing embryonic circulatory physiology requires accurate cardiac output and flow data. Despite recent applications of high-frequency ultrasound Doppler to the study of embryonic circulation, current Doppler analysis of volumetric flow is relatively crude. To improve Doppler derivation of volumetric flow, we sought a preliminary model of the spatial velocity profile in the mouse embryonic dorsal aorta using ultrasound biomicroscopy (UBM)-Doppler data. Embryonic hematocrit is 0.05-0.10 so rheologic properties must be insignificant. Low Reynolds numbers (Ͻ500) and Womersley parameters (Ͻ0.76) suggest laminar flow. UBM demonstrated a circular dorsal aortic cross section with no significant tapering. Low Dean numbers (Ͻ100) suggest the presence of minimal skewing of the spatial velocity profile. The inlet length allows for fully developed flow. There is no apparent aortic wall pulsatility. Extrapolation of prior studies to these vessel diameters (300-350 m) and flow velocities (ϳ50-200 mm/s) suggests parabolic spatial velocity profiles. Therefore, mouse embryonic dorsal aortic blood flow may correspond to Poiseuille flow in a straight rigid tube with parabolic spatial velocity profiles. As a first approximation, these results are an important step toward precise in utero ultrasound characterization of blood flow within the developing mammalian circulation. cardiac development; embryonic blood flow; physiology; ultrasound THE PHYSIOLOGICAL STUDY OF developing circulation remains technically challenging (for a review, see Ref. 37). The mouse is the primary model of mammalian development, but the assessment of developmental cardiovascular physiology, critical to the study of functional genomics, has lagged behind the recent advances in molecular cardiology. We recently (1, 36, 40) demonstrated that quantitative in utero study of mouse embryonic cardiovascular physiology is feasible using 40-to 50-MHz ultrasound biomicroscopy (UBM) and 43-MHz spectral pulsed-wave (PW) Doppler. UBM image-guided PW Doppler, in particular, is a powerful tool for the quantitative and noninvasive investigation of early mouse circulatory development, allowing for more physiologically relevant data than previously obtained (36).Precise characterization of developing embryonic circulatory physiology requires information on cardiac output and volumetric blood flow, allowing for insights into blood flow distribution and oxygen delivery. Volumetric blood flow (Q) in a given blood vessel may be calculated as Q ϭ vessel cross-sectional area ϫ time-averaged mean velocity Overall, current analysis of Doppler signals to provide volumetric blood flow information is very poorly developed (13). In Doppler assessment of cardiovascular physiology, several assumptions...

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“…18 -20 Yamada et al 18 reported that the backscatter intensity of blood increased dramatically with stagnant flow. Van der Heiden et al 19 showed that the increase in backscatter intensity depended on red cell aggregation. In an animal model, Fowlkes et al 20 showed that whole-blood thrombus increased its echogenicity over time and that this was related to the fibrin content.…”

Section: Ivus Appearancementioning

confidence: 99%

Incidence, Morphology, Angiographic Findings, and Outcomes of Intramural Hematomas After Percutaneous Coronary Interventions

et al. 2002

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Background-Intramural hematomas during percutaneous coronary intervention (PCI) have not been well studied. Methods and Results-We used intravascular ultrasound to determine the incidence, morphology, and clinical features of post-PCI intramural hematomas. In 905 patients with 1025 consecutive native coronary artery, non-in-stent restenosis lesions undergoing PCI, 72 hematomas were detected in 69 arteries in 68 patients. The incidence of intramural hematomas per artery was 6.7% (69 of 1025); 36% (26 of 72) involved the proximal reference artery, 18% (13 of 72) were confined to the lesion, and 46% (33 of 72) involved the distal reference artery. The entry site from the lumen into the hematoma was identified in 86% of hematomas (62 of 72) and had the appearance of a dissection into the media. Conversely, a re-entry site was identifiable in only 8% (6 of 72). The axial extension of the hematoma was distal in 63% and proximal in 37%. In 60% of the hematomas (42 of 72) the angiogram had the appearance of a dissection; in 11% (8 of 72), it appeared to be a new stenosis; and in 29% (22 of 72), no significant abnormality was detected. Non-Q-wave myocardial infarctions occurred in 26% of patients (17 of 65). In 3 patients, the creatine kinase-MB was not measured during the hospital stay. Repeat revascularization occurred in 2 patients in-hospital, 2 additional patients at 1 month, and 8 additional patients at 1 year. There were 3 sudden deaths at 1 year. Conclusions-Intravascular ultrasound identified intramural hematomas after 6.7% of PCIs. The mechanism appeared to be a dissection into the media where blood accumulated because of a lack of re-entry. A third of ultrasound-identified hematomas showed no angiographic abnormalities. There was a high rate of non-Q-wave myocardial infarction, need for repeat revascularization, and sudden death in patients with hematomas.

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Ultrasound backscatter at 30 MHz from human blood: Influence of rouleau size affected by blood modification and shear rate

Cited by 66 publications

References 24 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

Spatial velocity profile in mouse embryonic aorta and Doppler-derived volumetric flow: a preliminary model

Incidence, Morphology, Angiographic Findings, and Outcomes of Intramural Hematomas After Percutaneous Coronary Interventions

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