Thermal Pulse Decay Method for Simultaneous Measurement of Local Thermal Conductivity and Blood Perfusion: A Theoretical Analysis

1986 ◽  
Vol 108 (3) ◽  
pp. 208-214 ◽  
Author(s):  
H. Arkin ◽  
K. R. Holmes ◽  
M. M. Chen ◽  
W. G. Bottje
Keyword(s):  
Thermal Conductivity ◽  
Blood Flow ◽  
Theoretical Analysis ◽  
Simultaneous Measurement ◽  
Blood Perfusion ◽  
Perfusion Rate ◽  
Tissue Conductivity ◽  
Thermal Pulse ◽  
Measurement Protocol ◽  
Blood Perfusion Rate

Presented here is a theoretical analysis of the recently developed thermal pulse decay (TPD) method for a simultaneous measurement of local tissue conductivity and blood perfusion rate. The paper describes the theoretical model upon which the TPD method is based and details its capabilities and limitations. The theoretical aspects that affected the development of the measurement protocol are also discussed. The performance of the method is demonstrated with an experimental example which compares the measurements of local kidney blood perfusion rates made using the TPD method with the total renal blood flow obtained coincidentally using a blood flowmeter, in an anesthetized dog.

Thermography as a Means of Blood Perfusion Measurement

1979 ◽  
Vol 101 (4) ◽  
pp. 246-249 ◽  
Author(s):  
J. E. Francis ◽  
R. Roggli ◽  
T. J. Love ◽  
C. P. Robinson
Keyword(s):  
Blood Flow ◽  
Skin Temperature ◽  
Strain Gage ◽  
Infrared Camera ◽  
Blood Perfusion ◽  
The Body ◽  
Perfusion Rate ◽  
Perfusion Measurement ◽  
Blood Perfusion Rate ◽  
Human Forearm

The scanning infrared camera has been used to verify an analytical model relating blood perfusion rate to skin temperature. The blood perfusion rates were measured with both the mercury strain gage and the volume plethysmograph on the human forearm. Thermograms were taken of the forearm and temperature measured using an optical densitometer. Comparison of the volume plethysmograph with the strain gage, and the thermograms with the strain gage indicate thermography to be a useful means of measuring blood flow. Thermography has the advantages of being noninvasive and can be used to measure blood perfusion in parts of the body not easily monitored with occlusive techniques.

Prediction of skin burn injury. Part 2: Parametric and sensitivity analysis

2002 ◽  
Vol 216 (3) ◽  
pp. 171-183 ◽  
Author(s):  
E Y-K Ng ◽  
L T Chua
Keyword(s):  
Thermal Conductivity ◽  
Sensitivity Analysis ◽  
Burn Injury ◽  
Convective Heat Transfer Coefficient ◽  
Blood Perfusion ◽  
Tissue Temperature ◽  
Two Dimensional ◽  
Perfusion Rate ◽  
Injury Threshold ◽  
Blood Perfusion Rate

Part 2 of this paper presents an analysis of variance (ANOVA) for investigating the precedence of the various parameters, and the effects of varying these parameters, in assessment of burn injury resulting from the exposure of skin surface to heat sources. A one-dimensional model based on the finite difference method (FDM), as implemented in a spreadsheet software application, is applied to the assessment of burn injury. Henriques' theory of skin burns is used for determining the spatial and temporal extent of tissue damage. The ranks of the effects of various factors were obtained. It was found that the highest ranked factor is the initial tissue temperature followed by the thermal conductivity of the epidermal layer. The effect of blood perfusion rate is ranked much below the combinations of other factors. The results from the present numerical experiment agree well with the results obtained by Palla. Sensitivity analysis of the critical exposure levels was also carried out and results are discussed. In this study, the effects of the various parameters on injury threshold were investigated. Again, the results indicate that the four parameters: thermal conductivity of the epidermis and dermis, convective heat transfer coefficient and initial tissue temperature, have a pronounced influence on assessing the burn injury threshold. It was also found that fat thermal conductivity and blood perfusion rate have no obvious effect on injury threshold. A two-dimensional analysis was further conducted to determine the sensitivity of the predicted injury to the values of frequency factor, P, and apparent activation energy, Δ E, used in the models. Part 1 of this study details the development of the computer models based on the one- and two-dimensional bioheat equations.

scholarly journals Computational Modelling of Dual-Phase Lag Bioheat Process in Cooling of Cutaneous Tissue Exposed to High Heating for Burn Injury Prediction

2021 ◽  
Author(s):  
George Oguntala ◽  
Yim Fun Hu ◽  
Gbeminiyi Sobamowo
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Burn Injury ◽  
Blood Perfusion ◽  
Skin Tissue ◽  
Critical Parameters ◽  
Skin Burn ◽  
Perfusion Rate ◽  
Blood Perfusion Rate ◽  
Cutaneous Tissue

Abstract Heat transfer in biological systems is critical in analytic and therapeutic burn applications. Timely burn evaluation and appropriate clinical management are critical to ameliorate the treatment outcome of burn patients. To apply appropriate burn treatment, it is necessary to understand the thermal parameters of the skin. The paper aims to model the non-Fourier bioheat process in the human skin using a multi-domain trivariate spectral collocation method to determine skin burn injury with non-ideal properties of tissue, blood perfusion and metabolism. The skin tissue internal water evaporation during direct heating is considered. Parametric studies on the effects of skin tissue properties, initial temperature, blood perfusion rate and heat transfer parameters for the thermal response and exposure time of triple-layer cutaneous tissues are carried out. The study shows that the initial tissue temperature, the thermal conductivity of the epidermis and dermis, relaxation and thermalisation time and convective heat transfer coefficient are critical parameters necessary for skin burn injury baseline examination. The thermal conductivity and blood perfusion rate also exhibit negligible effects on the burn injury threshold of the cutaneous tissue. The present study is aimed to assist burn evaluation for reliable experimentation, design and optimisation of thermal therapy delivery.

Bone blood flow shown with F18 and the positron camera

1965 ◽  
Vol 209 (1) ◽  
pp. 65-70 ◽  
Author(s):  
Donald Van Dyke ◽  
Hal O. Anger ◽  
Yukio Yano ◽  
Carlos Bozzini
Keyword(s):  
Blood Flow ◽  
Extraction Efficiency ◽  
Blood Perfusion ◽  
Fluoride Ion ◽  
Bone Blood Flow ◽  
Perfusion Rate ◽  
Pathological Conditions ◽  
Blood Perfusion Rate ◽  
Fluoride Distribution ◽  
Initial Uptake

Development of the positron camera has made it possible to rapidly obtain pictures of the distribution of radioactive fluorine 18 in the living animal or human being. The distribution of F18 administered intravenously as fluoride ion is uneven in the normal skeleton. Furthermore, it is markedly altered in pathological conditions and accumulates at fracture sites, tumor sites, and in the lesions of Paget's disease. The initial uptake of fluoride in bone is dependent on the rate of delivery of the isotope to each bone (blood perfusion rate) and the extraction efficiency of that bone. Evidence is presented indicating the fluoride distribution in the skeleton is determined by differences in blood perfusion rate to the various bones rather than differences in extraction efficiency. We suggest that F18 distribution is an indicator of blood flow to bone.

scholarly journals Inert gas clearance from tissue by co-currently and counter-currently arranged microvessels

2012 ◽  
Vol 113 (3) ◽  
pp. 487-497 ◽  
Author(s):  
Y. Lu ◽  
C. C. Michel ◽  
W. Wang
Keyword(s):  
Blood Flow ◽  
Current Flow ◽  
Numerical Models ◽  
Blood Perfusion ◽  
Inert Gas ◽  
Perfusion Rate ◽  
Blood Perfusion Rate ◽  
Counter Current Flow ◽  
Physiological Values ◽  
Counter Current

To elucidate the clearance of dissolved inert gas from tissues, we have developed numerical models of gas transport in a cylindrical block of tissue supplied by one or two capillaries. With two capillaries, attention is given to the effects of co-current and counter-current flow on tissue gas clearance. Clearance by counter-current flow is compared with clearance by a single capillary or by two co-currently arranged capillaries. Effects of the blood velocity, solubility, and diffusivity of the gas in the tissue are investigated using parameters with physiological values. It is found that under the conditions investigated, almost identical clearances are achieved by a single capillary as by a co-current pair when the total flow per tissue volume in each unit is the same (i.e., flow velocity in the single capillary is twice that in each co-current vessel). For both co-current and counter-current arrangements, approximate linear relations exist between the tissue gas clearance rate and tissue blood perfusion rate. However, the counter-current arrangement of capillaries results in less-efficient clearance of the inert gas from tissues. Furthermore, this difference in efficiency increases at higher blood flow rates. At a given blood flow, the simple conduction-capacitance model, which has been used to estimate tissue blood perfusion rate from inert gas clearance, underestimates gas clearance rates predicted by the numerical models for single vessel or for two vessels with co-current flow. This difference is accounted for in discussion, which also considers the choice of parameters and possible effects of microvascular architecture on the interpretation of tissue inert gas clearance.

Estimation of Tissue Blood Perfusion Rate from Diffusible Indicator Measurements: A Sensitivity Analysis

1980 ◽  
Vol 102 (3) ◽  
pp. 258-264 ◽  
Author(s):  
A. Shitzer ◽  
R. C. Eberhart ◽  
J. Eisenfeld
Keyword(s):  
Sensitivity Analysis ◽  
Material Balance ◽  
Blood Perfusion ◽  
Tissue Perfusion ◽  
Optimal Time ◽  
Perfusion Rate ◽  
Experimental Conditions ◽  
Rate Analysis ◽  
Sensor Position ◽  
Blood Perfusion Rate

Recording the washout of indicator (for example, heat, radio-labeled dissolved gas, etc.) transiently introduced into tissue allows the estimation of tissue blood perfusion rate. Analysis of the washout data requires a material balance which appropriately accounts for all transport mechanisms and sources and sinks of the given indicator. From that balance one may perform a sensitivity analysis which specifies the susceptibility of the perfusion estimate to experimental errors in any of the pertinent parameters and variables. The sensitivity analysis is based on the normalized partial derivatives of tissue indicator concentration with respect to the experimental variables. The results indicate that the estimation of the tissue blood perfusion rate is highly sensitive to errors in the concentration of the diffusible indicator which dominate, by two orders of magnitude or more, the errors attributed to other parameters. For typical experimental conditions, the errors in the perfusion estimate due to the various parameters are shown to vary considerably, according to the sensor position and time of measurement. Based on this type of analysis, one may specify optimal temporal and spatial domains for the parameter estimation in order to minimize error propagation. The optimal time domains are shown to differ from those used in typical indicator washout analyses for estimating tissue perfusion rate.

Effects of laser acupuncture on blood perfusion rate

2006 ◽  
Author(s):  
Xian-ju Wang ◽  
Chang-chun Zeng ◽  
Han-ping Liu ◽  
Song-hao Liu ◽  
Liang-gang Liu
Keyword(s):  
Blood Perfusion ◽  
Laser Acupuncture ◽  
Perfusion Rate ◽  
Blood Perfusion Rate

A Sensitivity Analysis of the Thermal Pulse Decay Method for Measurement of Local Tissue Conductivity and Blood Perfusion

1986 ◽  
Vol 108 (1) ◽  
pp. 54-58 ◽  
Author(s):  
H. Arkin ◽  
K. R. Holmes ◽  
M. M. Chen
Keyword(s):  
Sensitivity Analysis ◽  
Measurement Errors ◽  
Blood Perfusion ◽  
Maximum Error ◽  
Experimental Protocol ◽  
Tissue Conductivity ◽  
Thermal Pulse ◽  
Local Tissue ◽  
Tissue Heating

The Thermal Pulse Decay (TPD) method for the determination of local tissue thermal conductivity and blood perfusion rate is based on a comparison of measured with theoretically calculated temperatures. A sensitivity analysis of the theoretical model is performed. This analysis supports the establishment of an experimental protocol which reduces the measurement errors: An “optimal” measurement time inverval for typical perfusion rates (up to 6 mL/mL/min) was found to be between 3 and 11 s after the heat pulse is turned off. Within this interval, the maximum error in determination of tissue conductivity and blood perfusion caused by experimental measurement errors is expected not to exceed 5 percent. The presently chosen pulse duration of 3 s is in agreement with the analysis as a good compromise between accuracy and excessive tissue heating.

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