Fiber-optic laser-Doppler anemometer microscope developed for the measurement of microvascular red cell velocity

doi:10.1016/0026-2862(90)90029-Q

Microvascular Research

Volume 40, Issue 3, November 1990, Pages 302-316

https://doi.org/10.1016/0026-2862(90)90029-Q Get rights and content

Abstract

A fiber-optic laser-Doppler anemometer microscope (FLDAM) was developed and its applicability to the study of microvascular blood flow was examined by measuring red cell velocities in vivo and in vitro. The FLDAM consists of an intravital microscope equipped with a fringe-mode back-scatter LDA. A data processing method of the Doppler signal which used frequency averaging over the entire frequency range of the power spectrum was developed. Spatial resolution of the FLDAM varied from 17 to 200 μm with 50X to 5X objectives. In vitro experiments showed that the red cell velocity obtained by the FLDAM was equal to the mean flow velocity, within the accuracy of the measurements, for tube diameters from 35 to 100 μm, mean velocity from 0.7 to 17 mm/sec, and feed hematocrit of 20%, when 10X or 20X objectives were used. In vivo red cell velocity measurements conducted with the FLDAM in microvessels of rat mesentery with diameters from 6.5 to 49 μm showed that red cell velocities were about $1 1.6$ times smaller than those obtained by the two-slit technique, which also suggests that the velocity obtained by the FLDAM corresponds to the mean flow velocity. This relationship was also established from theoretical considerations for the case where the FLDAM sampling volume covers the entire vessel cross section. Furthermore the frequency response of the FLDAM was established to be about 20 Hz, which was sufficient for measurement of pulsatile velocities in rat mesenteric microvessels.

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Citation Excerpt :
The RBC velocity measurement [14] can only be applied to the straight segments of a vessel. The laser Doppler velocimetry [7] is frequently employed in measuring the average and instantaneous velocity [27] in vivo. Although it is able to quantify blood flow of capillaries in a sampling volume [31], its resolution is not high as that of the capillaroscopy that assesses blood flow dynamics in one single capillary with a diameter close to the size of a RBC (10 μm or so).
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Microvascular Research

Abstract

References (18)

On-line volume flow rate and velocity profile measurement for blood in microvessels

Microvasc. Res.

In vitro and in vivo measurement of red cell velocity with epi- and transillumination

Microvasc. Res.

Letter to the Editor

Microvasc. Res.

In vivo and in vitro measurements in microvasculature with a laser

Microvasc. Res.

The application of an improved dual-slit photometric analyzer for volumetric flow rate measurements in microvessels

Microvasc. Res.

Hematocrit determination in small bore tubes from optical density measurements under white light illumination

Microvasc. Res.

Application of the “two-slit” photometric technique to the measurement of microvascular volumetric flow rates

Microvasc. Res.

A laser Doppler microscope

Opt. Commun.

In vivo and in vitro measurements of red cell velocity under epifluorescence microscopy

Microvasc. Res.

Cited by (20)

Pseudo three-dimensional vision-based nail-fold morphological and hemodynamic analysis

Understanding cardiovascular physiology in zebrafish and Xenopus larvae: The use of microtechniques

There is no valid evidence presented as to an impaired endothelial NO system in the stroke-prone spontaneously hypertensive rats

Fiber-optic laser-Doppler anemometer microscope applied to the cerebral microcirculation in rats

Relative blood velocity measurement in individual microvessels using the self-mixing effect in a fiber-coupled helium-neon laser

Red blood cell aggregation