Changes in Local Hepatic Blood Perfusion During Interstitial Laser-Induced Thermotherapy of Normal Rat Liver Measured by Interstitial Laser Doppler Flowmetry

1999 ◽  
Vol 14 (2) ◽  
pp. 143-149 ◽  
Author(s):  
C. Sturesson ◽  
K. Ivarsson ◽  
S. Andersson-Engels ◽  
K.-G. Tranberg
Keyword(s):  
Rat Liver ◽  
Laser Doppler Flowmetry ◽  
Blood Perfusion ◽  
Laser Doppler ◽  
Doppler Flowmetry ◽  
Normal Rat ◽  
Interstitial Laser

scholarly journals Laser Doppler Flowmetry versatile acquisition system with low quantization error

2018 ◽  
Vol 4 (1) ◽  
pp. 25
Author(s):  
Francesco Marrazzi ◽  
Frederic Truffer ◽  
Martial Geiser
Keyword(s):  
Laser Doppler Flowmetry ◽  
Analog Circuit ◽  
Scattered Light ◽  
Blood Perfusion ◽  
Electrical Signal ◽  
Laser Doppler ◽  
Physical Models ◽  
Acquisition System ◽  
Invasive Technique ◽  
Doppler Flowmetry

The Laser Doppler Flowmetry (LDF) is a non-invasive technique used to evaluate blood perfusion of various human tissues like the skin or the fundus of the eye. It is based on the scattering of light on moving red blood cells in tissue. Frequency shifted scattered light is detected and provide an electrical signal. Physical models for LDF use the DC and AC components of this signal. If AC is small relative to the DC, digitalization becomes an issue, and if more than two LDF signal acquisitions and analysis have to be done simultaneously, the device becomes expensive and bulky. We propose here a versatile and inexpensive acquisition system, which overcomes quantization errors issue by first separating DC from AC, then amplifying AC and finally recombining both signals before digitalization. We designed an analog circuit combined with a 12 bit analog-to-digital converter, a microcontroller unit and a Raspberry Pi2 (Rpi2) for the signal processing. Results are accessed remotely from the Rpi2 through HTTP protocol. Multiple systems can easily be used simultaneously for multichannel acquisitions.

scholarly journals Laser doppler flowmetry for human blood microcirculation assessment

2014 ◽  
Vol 95 (1) ◽  
pp. 63-69 ◽  
Author(s):  
I V Barhatov
Keyword(s):  
Blood Flow ◽  
Frequency Analysis ◽  
Laser Doppler Flowmetry ◽  
Maximum Amplitude ◽  
Blood Perfusion ◽  
Laser Doppler ◽  
Doppler Flowmetry ◽  
Functional Changes ◽  
Microcirculatory Disorders ◽  
The Impact

The prevention and treatment of various microcirculation disorders are one of the most important problems of medical practice. The difficulties of studying the microcirculation are related to the blood vessels small size and extensive branching within organ tissues. At present, various methods of microcirculation assessment using the laser Doppler flowmetry are applied in active clinical practice in our country. The review covers the main methods of laser Doppler flowmetry used for the diagnosis of various microcirculation disorders. The method is based on the determination of tissue blood perfusion by measuring the Doppler frequency shift while tissue is illuminated by a laser beam, followed by the registration of the reflected radiation from moving and stationary tissue components. Microcirculatory oscillation rhythm plays an important role, especially in early diagnosis of many diseases. The loss of certain types of oscillations at laser Doppler flowmetry is interpreted as «spectral narrowing» and serves as a diagnostic criterion for microcirculation deregulation, which is directly related to decreased blood perfusion and tissue hypotrophy. The use of amplitude-frequency analysis of blood flow oscillations can non-invasively evaluate the impact of the various components of microvascular tone, allowing to calculate an index of neurogenic and myogenic tone and bypass index. The amplitude-frequency analysis of the laser Doppler flowmetry spectrum uses normalized parameters determining the maximum amplitude of the blood flow oscillation in different bands, as well as their ratio - microcirculation effectiveness index. Hyperemic, spastic, spastic-atonic, structural and degenerative, congestive and stasic forms of various microcirculation disorders are marked out. Each of these microcirculatory disorders is characterized by a certain ratio of structural and functional changes and changes in blood velocity, as well as impaired barrier function. The main principles of the microcirculatory disorders are described.

scholarly journals A LASER DOPPLER FLOWMETRY FOR MEASURING THE PULP BLOOD PERFUSION IN TEETH WITH POSTOPERATIVE SENSITIVITY – a case report

2016 ◽  
Vol 22 (4) ◽  
pp. 1383-1384
Author(s):  
Vesela Stefanova ◽  
◽  
Neshka Manchorova ◽  
Desislava Georgieva ◽  
Angel Sapundgiev ◽  
...  
Keyword(s):  
Case Report ◽  
Laser Doppler Flowmetry ◽  
Blood Perfusion ◽  
Laser Doppler ◽  
Doppler Flowmetry ◽  
Postoperative Sensitivity

scholarly journals Validating Minimally Invasive Laser Doppler Flowmetry for Serial Bone Perfusion Measurements in Mice

2019 ◽  
Author(s):  
Nicholas J. Hanne ◽  
Elizabeth D. Easter ◽  
Jacqueline H. Cole
Keyword(s):  
Minimally Invasive ◽  
Laser Doppler Flowmetry ◽  
Femoral Artery ◽  
Interleukin 6 ◽  
Blood Perfusion ◽  
Laser Doppler ◽  
Serum Concentrations ◽  
Gait Patterns ◽  
Doppler Flowmetry

AbstractIn vivo laser Doppler flowmetry (LDF) has previously been used to quantify blood perfusion accurately at a single timepoint in the murine tibial metaphysis. However, this procedure entailed substantial disruption to soft tissues overlying the bone and caused notable localized inflammation for several weeks after the procedure, impeding serial measurements in the same mouse. In this study, we tested a less invasive technique to measure perfusion in the tibia with LDF and validated that it can be used serially in the same mouse without causing inflammation or gait perturbations. Twenty 14-week-old C57Bl/6J mice were evenly divided into groups that either had daily treadmill exercise or remained sedentary. Within these activity groups, mice were evenly subdivided into groups that received LDF measurements either weekly or only once at the study endpoint. Bone perfusion was measured with LDF in the anteromedial region of the right tibial metaphysis. Serum concentrations of interleukin 6, incision site wound area, and interlimb coordination during gait were measured weekly for four weeks. Tibial perfusion did not differ significantly between exercise and sedentary groups within the weekly or endpoint-only LDF groups at any timepoint. Perfusion was significantly increased in the third week in the weekly LDF group relative to measurements in the second and fourth weeks. Ligation of the femoral artery caused consistent, rapid reductions in tibial perfusion, validating that LDF is sensitive to changes in tibial blood supply. Weekly LDF procedures did not adversely affect gait, as interlimb coordination during treadmill locomotion was similar between weekly and endpoint-only LDF groups at every timepoint. Images of the incision site show wound closure within one week, and serum concentrations of interleukin 6 were not significantly different between weekly and endpoint-only groups. Together, these findings demonstrate that our minimally invasive LDF technique can be used for serial in vivo measurements of intraosseous blood perfusion without inducing localized inflammation or negatively affecting gait patterns in mice.HighlightsModified, minimally invasive laser Doppler flowmetry (LDF) technique was validated for serial measures of tibial perfusion in mice.Weekly LDF procedures did not induce inflammation or alter gait patterns that could confound metrics of interest in bone studies.Ligation of the femoral artery confirmed the LDF technique measures functional perfusion within the bone.

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