Single Fiber Laser-Doppler Flowmetry—Dependence on Wavelength and Tip Optics

Cai, Hongming; Larsson, Sven‐Erik; Öberg, Peter

doi:10.1117/1.429892

Cited by 5 publications

(4 citation statements)

References 11 publications

(16 reference statements)

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“…In its early stages of development, LDV was used to measure blood flow in the retina [97] and superficial muscles [98,99], and from inside the body opened surgically [100]. However, attenuation of light in tissue presented challenges with obtaining signals from deeper vessels without surgically opening the body.…”

Section: Laser Doppler Velocimetrymentioning

confidence: 99%

Fibre optic intravascular measurements of blood flow: A review

Mackle

Coote

Carr

et al. 2021

Sensors and Actuators A: Physical

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Fibre optic sensors are well suited to measuring fluid flow in many contexts, and recently there has been burgeoning interest in their application to direct, invasive measurement of blood flow within human vasculature. Depending on the sensing method used and assumptions made, these intravascular measurements of blood flow can provide information about local blood velocity, volumetric flow, and flowderived parameters. Fibre optic sensors can be readily integrated into medical devices, which are positioned into arteries and veins to obtain measurements that are inaccessible or cumbersome using non-invasive imaging modalities. Measurements of flow within coronary arteries is a particularly promising application of fibre optic sensing; recent studies have demonstrated the clinical utility of certain flow-based parameters, such as the coronary flow reserve (CFR) and the index of microcirculatory resistance (IMR). In this review, research and development of fibre optic flow sensors relevant to intravascular flow measurements are reviewed, with a particular focus on biomedical clinical translation.

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Section: Laser Doppler Velocimetrymentioning

confidence: 99%

Fibre optic intravascular measurements of blood flow: A review

Mackle

Coote

Carr

et al. 2021

Sensors and Actuators A: Physical

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“…The sensors that measure the light reflected from the tissue itself include invasive or noninvasive oximeters, laser Doppler flowmeters, and sensors for fluorescence and temperature measurements. [1][2][3][4] The other sensors use an appropriate transducer attached to the measurement site at the tip of the fiber for measurement of temperature, pressure, pH, or concentrations of other analytes. 1,[5][6][7] In some sensors the whole surface of a portion of the fiber serves as the measurement site by using the evanescent light through the unclad fiber for exiting fluorescence in molecules attached to the fiber surface.…”

Section: Introductionmentioning

confidence: 99%

Fiber Optic Sensor for the Measurement of Respiratory Chest Circumference Changes

et al. 1999

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A fiber optic sensor for the measurement of the respiratory depth has been developed. The sensor is composed of a bent optic fiber which is connected to an elastic section of a chest belt so that its radius of curvature changes during respiration due to respiratory chest circumference changes (RCCC). The measurement of light transmission through the bent fiber provides information on its changes in curvature since a higher fraction of light escapes through the core-cladding surface of a fiber bent to a lower radius of curvature. The sensor can quantitatively measure the RCCC, although in relative terms, and it is sensitive enough to detect changes of the chest circumference due to the heart beat. Measurements of the RCCC were simultaneously performed with photoplethysmography (PPG)-the measurement by light absorption of the cardiac induced blood volume changes in the tissue-and a significant correlation was found between the RCCC and some parameters of the PPG signal. The fiber optic respiratory depth sensor enables a quantitative assessment of the respiratory induced changes in the cardiovascular parameters. © 1999 Society of Photo-Optical Instrumentation Engineers.

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“…Therefore, the fringe-mode LDV cannot be used as a diagnostic device for blood flow velocity measurements. A fiber-optic LDV sensor has been developed as an alternative laser sensor that uses the LDV method [1][2][3][4]. Although this sensing method requires the sensor head to be inserted directly into the blood vessel, the associated risk is very low, because the optical fiber, as a sensor head, owing to its small diameter of 125 μm, can be easily and safely inserted into vessels for clinical use by using a catheter or a needle.…”

mentioning

confidence: 99%

Development of a Miniaturized Fiber-optic LDV Sensor for Local Blood Velocity Measurement

Kohri¹,

Tajikawa²,

Ohba³

2013

BER

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Abstract-A novel, less invasive, miniaturized fiber-optic laser Doppler velocimetry (LDV) sensor, which can be directly inserted into a blood vessel was developed for clinical use in measurements of local blood velocity. A convex lens-like surface was formed by a chemical etching on the fiber's tip that had a core diameter of 50 μm. A laser beam that was emitted from the fiber's tip was focused and formed the measuring volume. This fiber sensor was inserted at an insertion angle of 60° through an injection needle, into the flow duct of an acrylic pipe in which highly concentrated fluid, such as whole blood, was flowing in a pulsatile manner. The flow was modeled after human middle cerebral arterial flow. In this study, the local flow velocity and velocity profile across the duct were measured in the pulsatile flow of a dense suspension of a white pigment. The results were compared both with the results obtained using a fringe-mode LDV and with the results that were calculated on the basis of Womersley's oscillatory flow theory. Consequently, it was found that the local velocity and its profile in the pulsatile flow can be successfully measured using the present fiber-optic LDV sensor, which proved the capability of the sensor as a diagnostic device.

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Single Fiber Laser-Doppler Flowmetry—Dependence on Wavelength and Tip Optics

Cited by 5 publications

References 11 publications

Fibre optic intravascular measurements of blood flow: A review

Fibre optic intravascular measurements of blood flow: A review

Fiber Optic Sensor for the Measurement of Respiratory Chest Circumference Changes

Development of a Miniaturized Fiber-optic LDV Sensor for Local Blood Velocity Measurement

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