Measurement of blood flow in vivo by Laser Doppler Anemometry through a microscope1

Einav, S.; Berman, Herbert J.; Fuhro, Robert; DiGiovanni, P.R.; Fridman, J. D.; Fine, Susan B.

doi:10.3233/bir-1975-123-410

Cited by 27 publications

(7 citation statements)

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“…It has been previously suggested that non-continuum behavior of blood flow through such microvessels, with outer diameters between 5 and 80 μm, may lead to complex flow mechanisms that are not yet clearly understood [1]. Such concerns have prompted the adaptation of various optical techniques to measurement of the velocity profiles of blood flow both in vivo [3][4][5] and in vitro [6][7][8][9], often providing scattered and contradictory results.…”

Section: Introductionmentioning

confidence: 99%

“…The most commonly used methods for mapping blood flow velocity distribution have been double-slit photometry [6], video microscopy [10], laser-Doppler velocimetry (LDV) and anemometry (LDA) [3]. Studies of blood flow behavior at a microscopic level based on these techniques have been limited by several factors, including poor spatial resolution, limited accuracy, optical errors introduced by scattering and refraction at the walls of the microvessels, the high concentration of blood cells, and lack of sufficient computing power for reliable image and signal processing [11].…”

Section: Introductionmentioning

confidence: 99%

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Assessment of the flow velocity of blood cells in a microfluidic device using joint spectral and time domain optical coherence tomography

Bukowska¹,

Derzsi²,

Tamborski³

et al. 2013

Opt. Express

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Although Doppler optical coherence tomography techniques have enabled the imaging of blood flow in mid-sized vessels in biological tissues, the generation of velocity maps of capillary networks remains a challenge. To better understand the origin and information content of the Doppler signal from small vessels and limitations of such measurements, we used joint spectral and time domain optical coherence tomography to monitor the flow in a model, semitransparent microchannel device. The results obtained for Intralipid, whole blood, as well as separated red blood cells indicate that the technique is suitable to record velocity profiles in vitro, in a range of microchannel configurations.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Assessment of the flow velocity of blood cells in a microfluidic device using joint spectral and time domain optical coherence tomography

Bukowska¹,

Derzsi²,

Tamborski³

et al. 2013

Opt. Express

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show abstract

“…The fundamental instrumentation employed in the first approach may be used in velocity measurement (Ling et al, 1968). Laser Doppler Velocimeters (LDVs) have been widely used because of their noninvasiveness and wide bandwidth (Einav et al, 1975(Einav et al, , 1990Friedman and Deters, 1987;Friedman et al. 1981;Ku ('I al., 1985: Mark ~'t (I/.. 1989: Walburn and Stein, 1982.…”

Section: Introductionmentioning

confidence: 99%

Errors in the estimation of arterial wall shear rates that result from curve fitting of velocity profiles

Lou

Yang

Stein

1993

Journal of Biomechanics

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An analysis was performed to determine the error that results from the estimation of the wall shear rates based on linear and quadratic curve-fittings of the measured velocity profiles. For steady, fully developed flow in a straight vessel, the error for the linear method is linearly related to the distance between the probe and the wall, dr1, and the error for the quadratic method is zero. With pulsatile flow, especially a physiological pulsatile flow in a large artery, the thickness of the velocity boundary layer, delta is small, and the error in the estimation of wall shear based on curve fitting is much higher than that with steady flow. In addition, there is a phase lag between the actual shear rate and the measured one. In oscillatory flow, the error increases with the distance ratio dr1/delta and, for a quadratic method, also with the distance ratio dr2/dr1, where dr2 is the distance of the second probe from the wall. The quadratic method has a distinct advantage in accuracy over the linear method when dr1/delta << 1, i.e. when the first velocity point is well within the boundary layer. The use of this analysis in arterial flow involves many simplifications, including Newtonian fluid, rigid walls, and the linear summation of the harmonic components, and can provide more qualitative than quantitative guidance.

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“…As a particle moves through, a periodic signal will be obtained at a detector, the frequency of this being proportional to the velocity of the scatterer . Combining the laser Doppler anemometer with a microscope to form a laser Doppler microscope anemometer could increase spatial resolution …”

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confidence: 99%

Velocity Measurement of Particles Flowing in a Microfluidic Chip Using Shah Convolution Fourier Transform Detection

2001

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A noninvasive radiative technique, based on Shah convolution Fourier transform detection, for velocity measurement of particles in fluid flows in a microfluidic chip, is presented. It boasts a simpler instrumental setup and optical alignment than existing measurement methods and a wide dynamic range of velocities measurable. A glass-PDMS microchip with a layer of patterned Cr to provide multiple detection windows which are 40 microns wide and 70 microns apart is employed. The velocities of fluorescent microspheres, which were electrokinetically driven in the channel of the microfluidic chip, were determined. The effects of increasing the number of detection windows and sampling period were investigated. This technique could have wide applications, ranging from the determination of the velocity of particles in pressure-driven flow to the measurement of electrophoretic mobilities of single biological cells.

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Measurement of blood flow in vivo by Laser Doppler Anemometry through a microscope1

Cited by 27 publications

References 0 publications

Assessment of the flow velocity of blood cells in a microfluidic device using joint spectral and time domain optical coherence tomography

Assessment of the flow velocity of blood cells in a microfluidic device using joint spectral and time domain optical coherence tomography

Errors in the estimation of arterial wall shear rates that result from curve fitting of velocity profiles

Velocity Measurement of Particles Flowing in a Microfluidic Chip Using Shah Convolution Fourier Transform Detection

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