Laser Doppler fiberscope anemometer for in-vivo blood flow measurements

1993 ◽  
Author(s):  
Shmuel Einav
Keyword(s):  
Blood Flow ◽  
Laser Doppler ◽  
Flow Measurements ◽  
Blood Flow Measurements

Laser-Doppler perfusion imaging of microvascular blood flow in rabbit tenuissimus muscle

1995 ◽  
Vol 269 (4) ◽  
pp. H1496-H1500 ◽  
Author(s):  
M. Linden ◽  
A. Sirsjo ◽  
L. Lindbom ◽  
G. Nilsson ◽  
A. Gidlof
Keyword(s):  
Blood Flow ◽  
Microscopic Observation ◽  
Atmospheric Oxygen ◽  
Tissue Perfusion ◽  
Laser Doppler ◽  
Microvascular Blood Flow ◽  
Flow Measurements ◽  
Flow Changes ◽  
Blood Flow Measurements

To evaluate a newly developed high-resolution laser-Doppler perfusion imager (HR-LDPI) for analysis of local tissue perfusion, blood flow measurements in the rabbit tenuissimus muscle were carried out in combination with intravital microscopic observation. The principle of the LDPI method is based on a low-power laser beam scan of the exposed tissue from which a two-dimensional color-coded perfusion map is created through computerized signal analysis. The perfusion of the tenuissimus muscle prepared for microscopic observation was analyzed in a 5 mm x 8 mm area as the muscle was exposed to atmospheric oxygen tension (Po2; 20 kPa), a low Po2 (approximately 3 kPa), and after vasodilatation induced by topical application of prostaglandin E2 (PGE2). In selected areas free from larger vessels, a significantly lower perfusion average reading was demonstrated under high Po2 conditions compared with low Po2 conditions (P < 0.05, n = 5 animals), and application of PGE2 gave rise to an average reading significantly higher than that at low Po2 (P < 0.01, n = 6 animals). The results were in good agreement with the flow changes observed microscopically, and the architecture of the microvascular network, as depicted by in vivo micrographs, was clearly recognizable in the perfusion images. In conclusion, blood flow changes in the rabbit tenuissimus muscle induced by various stimuli were quantitated with the HR-LDPI method and could be spatially resolved in great detail, illustrating the potential of using HR-LDPI for analysis of local blood flow and to reveal spatial perfusion heterogeneity in tissues.

Hybrid blood flow probe for simultaneous H2 clearance and laser-Doppler velocimetry

1987 ◽  
Vol 253 (4) ◽  
pp. G573-G581 ◽  
Author(s):  
G. R. DiResta ◽  
J. W. Kiel ◽  
G. L. Riedel ◽  
P. Kaplan ◽  
A. P. Shepherd
Keyword(s):  
Blood Flow ◽  
Laser Doppler Velocimetry ◽  
Regional Blood Flow ◽  
Laser Doppler ◽  
Doppler Velocimetry ◽  
Flow Probe ◽  
Flow Measurements ◽  
Blood Flow Measurements ◽  
Light Guides ◽  
The Relationship

To perform two independent regional blood flow measurements in tissue volumes of similar dimensions, we designed a hybrid blood flow probe capable of measuring regional perfusion by both laser-Doppler velocimetry (LDV) and H2 clearance. The probe consisted of two fiber-optic light guides to conduct light between the surface of tissue of interest and a laser-Doppler blood flowmeter. Also contained within the probe were a platinum 25-microns H2-sensing electrode and a 125-microns H2-generating electrode. The probe can thus be used to measure local perfusion with H2 clearance. The H2 can either be inhaled or can be generated electrochemically at the locus of interest. Evaluation of the probe in the canine gastric mucosa indicated 1) that the relationship between mucosal flow measurements made simultaneously with H2 clearance and LDV was highly significant and linear and 2) that H2 clearance could potentially be used to calibrate the laser-Doppler blood flowmeter in absolute units. The methods of constructing the flow probes are discussed in detail.

Clinical Evaluation of Laser Doppler Blood Flow Measurements in Free Flaps

1987 ◽  
Vol 18 (3) ◽  
pp. 212-217 ◽  
Author(s):  
Marcus Walkinshaw ◽  
Alan Holloway ◽  
Ann Bulkley ◽  
Loren H. Engrav
Keyword(s):  
Blood Flow ◽  
Clinical Evaluation ◽  
Free Flaps ◽  
Laser Doppler ◽  
Flow Measurements ◽  
Blood Flow Measurements

Blood Flow Measurements in the Ears of Patients Receiving Cochlear Implants

2002 ◽  
Vol 111 (11) ◽  
pp. 998-1001 ◽  
Author(s):  
Tsutomu Nakashima ◽  
Taku Hattori ◽  
Eisuke Sato ◽  
Michihiko Sone ◽  
Mitsuo Tominaga
Keyword(s):  
Blood Flow ◽  
Cochlear Implants ◽  
Cochlear Implantation ◽  
Internal Auditory Canal ◽  
Laser Doppler ◽  
Outer Diameter ◽  
Cochlear Blood Flow ◽  
Flow Measurements ◽  
Doppler Flowmetry ◽  
Blood Flow Measurements

We measured cochlear blood flow in 12 patients who received cochlear implants, using a laser-Doppler probe with an outer diameter of 0.8 mm. The subjects had congenital deafness, idiopathic progressive sensorineural hearing loss, Waardenburg's syndrome, narrow internal auditory canal, or sudden deafness. Putting the probe tip to the site of drilling for cochlear implantation, we measured blood flow before, during, and after the cochlear bony wall was opened. The laser-Doppler output was confirmed even after the tip of the probe was inserted into the perilymphatic space in all cases. Our results revealed that blood flow was maintained in all cochleas, although there was a probability of reduction in blood flow volume. We conclude that laser-Doppler flowmetry is both relatively safe and useful for measuring blood flow in the ears during cochlear implantation procedures.

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