A Comparison of Laser Doppler and Intravital Microscopic Measures of Cochlear Blood Flow

1989 ◽  
Vol 101 (3) ◽  
pp. 375-384 ◽  
Author(s):  
M. J. LaRouere ◽  
J. S. Sillman ◽  
A. L. Nuttall ◽  
J. M. Miller
Keyword(s):  
Blood Flow ◽  
Measurement Techniques ◽  
Lateral Wall ◽  
Laser Doppler ◽  
Spontaneous Respiration ◽  
Cochlear Blood Flow ◽  
Doppler Flowmetry ◽  
Two Measures ◽  
Positive Correlations ◽  
Relationship Of

Many inner ear disorders may be caused by alterations in cochlear blood flow (CBF). However, each measurement technique used to monitor CBF has limitations in examining the relationship between otopathologic states and blood flow. This study Investigates laser Doppler flowmetry (LDF) and its fundamental drawback: The unknown relationship of LDF output to actual CBF. LDF readings are directly compared with concurrent intravital microscopy (IVM) measures of erythrocyte velocity in the lateral wall of the guinea pig cochlea. Positive end expiratory pressure, spontaneous respiration of 5% and 10% carbon dioxide, phenylephrine, and direct electrical stimulation of the cochlea were used to manipulate CBF. High, positive correlations were found between simultaneous LDF and IVM measurements of CBF. In addition, the study demonstrated that current microdissection techniques used to perform IVM do not cause changes in CBF. IVM measurements of CBF are a more sensitive indicator of CBF changes than are LDF measures. Despite the high correlation between measurement techniques within a single manipulation, simultaneous LDF and IVM measurements differed between manipulations. This may reflect regional changes in CBF affected by these manipulations and differences in the sampled vascular beds contributing to these two measures. It is unlikely that a single calibration factor can be defined that would allow the conversion of LDF output to actual units of blood flow across different manipulations used to alter CBF.

Evaluation of cochlear blood flow measurement by laser Doppler flowmetry

2003 ◽  
Author(s):  
T. Tamura ◽  
A. Okamoto ◽  
N. Kobayashi ◽  
K. Yokoyama ◽  
M. Hasegawa ◽  
...  
Keyword(s):  
Blood Flow ◽  
Laser Doppler Flowmetry ◽  
Flow Measurement ◽  
Laser Doppler ◽  
Blood Flow Measurement ◽  
Cochlear Blood Flow ◽  
Doppler Flowmetry

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.

scholarly journals Cochlear blood flow measured by averaged laser Doppler flowmetry (ALDF)

1994 ◽  
Vol 77 (1-2) ◽  
pp. 200-206 ◽  
Author(s):  
Tianying Ren ◽  
P. Bradley Brechtelsbauer ◽  
Josef M. Miller ◽  
Alfred L. Nuttall
Keyword(s):  
Blood Flow ◽  
Laser Doppler Flowmetry ◽  
Laser Doppler ◽  
Cochlear Blood Flow ◽  
Doppler Flowmetry

Recent Advances in Cochlear Blood Flow Measurements

1988 ◽  
Vol 97 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Jonathon S. Sillman ◽  
Michael J. Larouere ◽  
Alfred L. Nuttall ◽  
Merle Lawrence ◽  
Josef M. Miller
Keyword(s):  
Blood Flow ◽  
Hearing Loss ◽  
Inner Ear ◽  
Laser Doppler ◽  
Control Mechanisms ◽  
Clinical Value ◽  
Cochlear Blood Flow ◽  
Flow Measurements ◽  
Local Flow ◽  
Doppler Flowmetry

Changes in blood flow to the inner ear have been thought to influence or underlie a number of cochlear diseases, including some forms of noise-induced hearing loss, sudden hearing loss, and Meniere's disease. Recently, important advances have been made in two technologies for the study of cochlear blood flow. The first is in the area of vital microscopic studies of cochlear microcirculation, and the second is based on the introduction of laser technology in the form of laser Doppler flowmetry. In this report, measurements are given of changes in cochlear circulation caused by carbon dioxide breathing, intravenous phenylephrine injection, systemic hemodilution, positive end expiratory pressure, and direct electrical stimulation of the cochlea. From these changes, we observe that cochlear blood circulation responds to systemic blood pressure alterations and is subject to local flow control mechanisms. Linearity and speed of response of the laser Doppler instrumentation also are shown. These advances show promise for contributing to our knowledge of control mechanisms of inner ear blood flow and for revealing the influence of various pharmacologic agents of potential clinical value.

scholarly journals Historical reviews of the assessment of human cardiovascular function: interrogation and understanding of the control of skin blood flow

2019 ◽  
Vol 120 (1) ◽  
pp. 1-16 ◽  
Author(s):  
David. A. Low ◽  
Helen Jones ◽  
N. Tim Cable ◽  
Lacy M. Alexander ◽  
W. Larry Kenney
Keyword(s):  
Blood Flow ◽  
Skin Blood Flow ◽  
Vascular Function ◽  
Muscle Blood Flow ◽  
Measurement Techniques ◽  
Two Dimensions ◽  
Laser Speckle ◽  
Laser Doppler ◽  
Skin Area ◽  
Doppler Flowmetry

AbstractSeveral techniques exist for the determination of skin blood flow that have historically been used in the investigation of thermoregulatory control of skin blood flow, and more recently, in clinical assessments or as an index of global vascular function. Skin blood flow measurement techniques differ in their methodology and their strengths and limitations. To examine the historical development of techniques for assessing skin blood flow by describing the origin, basic principles, and important aspects of each procedure and to provide recommendations for best practise. Venous occlusion plethysmography was one of the earliest techniques to intermittently index a limb’s skin blood flow under conditions in which local muscle blood flow does not change. The introduction of laser Doppler flowmetry provided a method that continuously records an index of skin blood flow (red cell flux) (albeit from a relatively small skin area) that requires normalisation due to high site-to-site variability. The subsequent development of laser Doppler and laser speckle imaging techniques allows the mapping of skin blood flow from larger surface areas and the visualisation of capillary filling from the dermal plexus in two dimensions. The use of iontophoresis or intradermal microdialysis in conjunction with laser Doppler methods allows for the local delivery of pharmacological agents to interrogate the local and neural control of skin blood flow. The recent development of optical coherence tomography promises further advances in assessment of the skin circulation via three-dimensional imaging of the skin microvasculature for quantification of vessel diameter and vessel recruitment.

The effect of tranexamic acid on cochlear blood flow in guinea pigs measured by laser Doppler flowmetry

2001 ◽  
Vol 28 (3) ◽  
pp. 215-218 ◽  
Author(s):  
Yen Hai Tran ◽  
Katsuichiro Ohsaki ◽  
Hitoshi Houchi ◽  
Teruhiro Ogawa ◽  
Chun-Sheng Zhu ◽  
...  
Keyword(s):  
Blood Flow ◽  
Tranexamic Acid ◽  
Laser Doppler Flowmetry ◽  
Guinea Pigs ◽  
Laser Doppler ◽  
Cochlear Blood Flow ◽  
Doppler Flowmetry
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