scholarly journals Thermography Quantification of Human Perfusion Thermal Signature

2018 ◽  
Author(s):  
Abbas K. AlZubaidi ◽  
Ahmed F. Hussein ◽  
Mena Basil ◽  
Qais Ahmed Habash
Keyword(s):  
Blood Flow ◽  
Infrared Thermography ◽  
Blood Perfusion ◽  
Bioheat Transfer ◽  
Thermal Excitation ◽  
Thermal Imager ◽  
Flow Monitoring ◽  
Air Stream ◽  
Measurement Protocol ◽  
The Impact

Blood perfusion quantification is important vital parameters in different diagnostic procedure, using infrared thermography imaging; it is reliable to use this technique as non-contact, non-invasive blood flow measurement method. Therefore, we developed a measurement protocol for blood flow over the arm's anterior surface. By using the superficial brachial and radial veins to be monitored under the impact of cold-excitation of (2 °C to 5 °C), the blood perfusion signal was detected using thermal imager of long-wave infrared spectral range (LWIR, 7μm - 14 μm). The simulation of Penne's bioheat transfer equation was performed to be compared with results obtained from the infrared thermography. Furthermore, the proposed blood flow monitoring using external adjusting of the excitation temperature, by using (cold-compress, or cold air-stream) applied to the region under testing. The signal detected resembles to the hemodynamic pulse of the superficial veins, in the definition of systolic and diastolic phases of the cardiac cycle. Moreover, statistical analysis applied to the BFIRT signals from 24 subjects to estimate the skin's mean temperature after recovery from the thermal excitation.

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.

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.

Impact of wall filter selection on the detection of vasomotor changes in the brachial artery: a pilot study

2009 ◽  
Vol 34 (2) ◽  
pp. 212-215
Author(s):  
Michel J. Johnson ◽  
J. Kevin Shoemaker
Keyword(s):  
Blood Flow ◽  
Forearm Blood Flow ◽  
Lower Body Negative Pressure ◽  
High Amplitude ◽  
Surrounding Tissue ◽  
Peripheral Blood Flow ◽  
Low Velocity ◽  
Flow Monitoring ◽  
Ultrasound Assessment ◽  
The Impact

During Doppler ultrasound assessment of blood flow, a wall filter is used to reduce or eliminate high-amplitude, low-velocity signals from the vessel wall and the surrounding tissue. This study investigated the impact of a range of wall filters (22 Hz, 75 Hz, 128 Hz, and 252 Hz) on the accuracy of forearm blood flow monitoring during the sympathoexcitatory application of lower body negative pressure, when peripheral blood flow may decrease substantially. The 252 Hz filter eliminated diastolic flow in 4 of 10 participants. In the remaining participants, the 252 Hz filter minimized the sensitivity of the pulsatility index. The interpretation of physiological responses could ultimately be compromised by using filters beyond 128 Hz.

scholarly journals In vitro investigation of the impact of pulsatile blood flow on the vascular architecture of decellularized porcine kidneys

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Peter R. Corridon
Keyword(s):  
Blood Flow ◽  
Blood Perfusion ◽  
Pulsatile Blood Flow ◽  
Venous Outflow ◽  
Venous Flow ◽  
Vascular Architecture ◽  
Arterial Perfusion ◽  
In Vitro Investigation ◽  
The Impact

AbstractA method was established using a scaffold-bioreactor system to examine the impact pulsatile blood flow has on the decellularized porcine kidney vascular architecture and functionality. These scaffolds were subjected to continuous arterial perfusion of whole blood at normal physiological (650 ml/min and 500 ml/min) and pathophysiological (200 ml/min) rates to examine dynamic changes in venous outflow and micro-/macrovascular structure and patency. Scaffolds subjected to normal arterial perfusion rates observed drops in venous outflow over 24 h. These reductions rose from roughly 40% after 12 h to 60% after 24 h. There were no apparent signs of clotting at the renal artery, renal vein, and ureter. In comparison, venous flow rates decreased by 80% to 100% across the 24 h in acellular scaffolds hypoperfused at a rate of 200 ml/min. These kidneys also appeared intact on the surface after perfusion. However, they presented several arterial, venous, and ureteral clots. Fluoroscopic angiography confirmed substantial alterations to normal arterial branching patterns and patency, as well as parenchymal damage. Scanning electron microscopy revealed that pulsatile blood perfusion significantly disrupted glomerular microarchitecture. This study provides new insight into circumstances that limit scaffold viability and a simplified model to analyze conditions needed to prepare more durable scaffolds for long-term transplantation.

Impact of intrinsic blood flow regulation in cirrhosis: maintenance of hepatic arterial buffer response

2000 ◽  
Vol 279 (2) ◽  
pp. G454-G462 ◽  
Author(s):  
Sven Richter ◽  
Isabella Mücke ◽  
Michael D. Menger ◽  
Brigitte Vollmar
Keyword(s):  
Blood Flow ◽  
Venous Blood ◽  
Blood Perfusion ◽  
Flow Regulation ◽  
Arterial Blood Flow ◽  
Venous Blood Flow ◽  
Total Blood ◽  
Arterial Blood ◽  
Blood Flow Regulation ◽  
The Impact

The hepatic arterial buffer response (HABR) effectively controls total blood perfusion in normal livers, but little is known about blood flow regulation in cirrhosis. We therefore studied the impact of HABR on blood perfusion of cirrhotic livers in vivo. After 8-wk CCl4 treatment to induce cirrhosis, 18 anesthetized rats (and 18 noncirrhotic controls) were used to simultaneously assess portal venous and hepatic arterial inflow with miniaturized ultrasonic flow probes. Stepwise hepatic arterial blood flow (HAF) or portal venous blood flow (PVF) reduction was performed. Cirrhotic livers revealed a significantly reduced total hepatic blood flow (12.3 ± 0.9 ml/min) due to markedly diminished PVF (7.3 ± 0.8 ml/min) but slightly increased HAF (5.0 ± 0.6 ml/min) compared with noncirrhotic controls (19.0 ± 1.6, 15.2 ± 1.3, and 3.8 ± 0.4 ml/min). PVF reduction caused a significant HABR, i.e., increase of HAF, in both normal and cirrhotic livers; however, buffer capacity of cirrhotic livers exceeded that of normal livers ( P < 0.05) by 1.7- to 4.5-fold (PVF 80% and 20% of baseline). Persistent PVF reduction for 1, 2, and 6 h demonstrated constant HABR in both groups. Furthermore, HABR could be repetitively provoked, as analyzed by intermittent PVF reduction. HAF reduction did not induce changes of portal flow in either group. Because PVF is reduced in cirrhosis, the maintenance of HAF and the preserved HABR must be considered as a protective effect on overall hepatic circulation, counteracting impaired nutritive blood supply via the portal vein.

Effekt of blood flow shutdown on the vein damage when exposed to HIFU

2017 ◽  
pp. 46-50
Author(s):  
Н.Н. Петрищев ◽  
Д.Ю. Семенов ◽  
А.Ю. Цибин ◽  
Г.Ю. Юкина ◽  
А.Е. Беркович ◽  
...  
Keyword(s):  
Blood Flow ◽  
Structural Changes ◽  
Focused Ultrasound ◽  
Vena Cava ◽  
Posterior Wall ◽  
High Intensity Focused Ultrasound ◽  
Vein Wall ◽  
Ultrasound Exposure ◽  
Isolated Segment ◽  
The Impact

The purpose. In the study we investigated the impact of the partial blood flow shutdown on structural changes in the rabbit vena cava posterior wall after exposure to high-intensity focused ultrasound (HIFU). Methods. Ultrasound Exposure: frequency of 1.65 MHz, the ultrasound intensity in the focus of 13.6 kW/cm, the area of the focal spot 1 mm, continuous ultrasound, exposure for 3 seconds. Results. Immediately after HIFU exposure all layers of the vein wall showed characteristic signs of thermal damage. A week after exposure structural changes in the intima, media and adventitia was minimal in the part of vessel with preserved blood flow, and after 4 weeks the changes were not revealed. A week after HIFU exposure partial endothelium destruction, destruction of myocytes, disorganization and consolidation of collagen fibers of the adventitia were observed in an isolated segment of the vessel, and in 4 weeks endothelium restored and signs of damage in media and adventitia persisted, but were less obvious than in a week after exposure. Conclusion. The shutdown of blood flow after exposure to HIFU promotes persistent changes in the vein wall. Vein compression appears to be necessary for the obliteration of the vessel, when using HIFU-technology.

scholarly journals PSV-16 Infrared thermography technology as a promising tool for assessing temperament of water buffaloes

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 220-221
Author(s):  
Caroline L Francisco ◽  
André M Castilhos ◽  
Daiane C Marques da Silva ◽  
Fabiola Martinez da Silva ◽  
Aline S Aranha ◽  
...  
Keyword(s):  
Infrared Thermography ◽  
Fixed Effects ◽  
Thermal Imager ◽  
Initial Body Weight ◽  
Water Buffaloes ◽  
Promising Tool ◽  
Genetic Groups ◽  
Body Regions ◽  
The Mean ◽  
Positive Correlations

Abstract This study evaluated the use of the infrared thermography (IT) as a tool to identify the temperament of 75 non-castrated water buffaloes (390±32 days of age; 310±61.27 kg of initial body weight) of 3 genetic groups (GG:Jafarabadi, Mediterranean, and Murrah; n = 25 for each GG). The animals were classified for temperament through the temperament score (TSc) obtained by the mean of the sum of the scores of the time of entry into the squeeze chute (1 to 5: 1=greater time spent for entry; 5=less time spent for entry) and the exit velocity score (1 to 5: 1=lower speed; 5=higher speed) calculated after the period of adaptation to the feedlot (d0). The animals were categorized into adequate (ADQ; TSc≤3) or excitable (EXC; TSc &gt;3) temperaments. The rectal temperature was measured and IT images were obtained (Testo 882 Thermal Imager, Testo, Inc, Germany) from regions of the chest, eye, snout, cheek, foreleg (left side), ribs, hind legs, rear area (left side), and scrotum on d0. Data were analyzed using MIXED procedure in SAS, considering the GG, temperament, and the resulting interaction as fixed effects. Correlation was analyzed using the CORR procedure of SAS. There were no effects of interactions (P ≥ 0.14). ADQ animals showed lower rectal (P = 0.02) and ribs (P = 0.05) temperatures than EXC animals (Table1). Tendencies for temperament effect were detected for chest (P = 0.06) and rear area (P = 0.07). There was no effect of temperament for other variables (P = 0.19). Positive correlations were verified between the TSc and rectal (r=0.36; P &lt; 0.01), chest (r=0.35; P &lt; 0.01), and rear area (r=0.33; P &lt; 0.01) temperatures. Tendency for a positive correlation was detected between TSc and scrotum (r=0.23; P = 0.07). In conclusion, the temperament causes changes in the temperature of some body regions suggesting the IT technology may be a promising tool for assessing the temperament of water buffaloes. Supported by FAPESP (#2018/25939-1; #2014/05473-7).

scholarly journals Advanced Constitutive Modeling of the Thixotropic Elasto-Visco-Plastic Behavior of Blood: Steady-State Blood Flow in Microtubes

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 367
Author(s):  
Konstantinos Giannokostas ◽  
Yannis Dimakopoulos ◽  
Andreas Anayiotos ◽  
John Tsamopoulos
Keyword(s):  
Blood Flow ◽  
Steady State ◽  
Constitutive Model ◽  
Blood Plasma ◽  
Constitutive Modeling ◽  
Flow Direction ◽  
Momentum Balance ◽  
Plastic Behavior ◽  
Flow Investigation ◽  
The Impact

The present work focuses on the in-silico investigation of the steady-state blood flow in straight microtubes, incorporating advanced constitutive modeling for human blood and blood plasma. The blood constitutive model accounts for the interplay between thixotropy and elasto-visco-plasticity via a scalar variable that describes the level of the local blood structure at any instance. The constitutive model is enhanced by the non-Newtonian modeling of the plasma phase, which features bulk viscoelasticity. Incorporating microcirculation phenomena such as the cell-free layer (CFL) formation or the Fåhraeus and the Fåhraeus-Lindqvist effects is an indispensable part of the blood flow investigation. The coupling between them and the momentum balance is achieved through correlations based on experimental observations. Notably, we propose a new simplified form for the dependence of the apparent viscosity on the hematocrit that predicts the CFL thickness correctly. Our investigation focuses on the impact of the microtube diameter and the pressure-gradient on velocity profiles, normal and shear viscoelastic stresses, and thixotropic properties. We demonstrate the microstructural configuration of blood in steady-state conditions, revealing that blood is highly aggregated in narrow tubes, promoting a flat velocity profile. Additionally, the proper accounting of the CFL thickness shows that for narrow microtubes, the reduction of discharged hematocrit is significant, which in some cases is up to 70%. At high pressure-gradients, the plasmatic proteins in both regions are extended in the flow direction, developing large axial normal stresses, which are more significant in the core region. We also provide normal stress predictions at both the blood/plasma interface (INS) and the tube wall (WNS), which are difficult to measure experimentally. Both decrease with the tube radius; however, they exhibit significant differences in magnitude and type of variation. INS varies linearly from 4.5 to 2 Pa, while WNS exhibits an exponential decrease taking values from 50 mPa to zero.

scholarly journals Anti-N-Methyl-D-Aspartate Receptor Encephalitis with Decrease in Blood Flow in Cerebellum

2021 ◽  
pp. 17-23
Author(s):  
Koji Obara ◽  
Tomoko Ono ◽  
Itaru Toyoshima
Keyword(s):  
Working Memory ◽  
Blood Flow ◽  
Ovarian Teratoma ◽  
Emission Computed Tomography ◽  
High Dose ◽  
Promising Alternative ◽  
Flow Monitoring ◽  
Aspartate Receptor ◽  
Nmdar Encephalitis ◽  
Consciousness Disturbance

In anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis, progressive cerebellar atrophy potentially leads to severe sequelae. We encountered a patient with anti-NMDAR antibody encephalitis who showed a decrease of blood flow in the cerebellum. A 15-year-old girl presented with consciousness disturbance. Influenza encephalopathy was suspected, and she was treated with glucocorticoid pulse therapy, high-dose intravenous immunoglobulins, and plasma exchange sequentially. She subsequently underwent left oophorectomy due to the presence of anti-NMDAR antibodies and a left ovarian teratoma. In spite of the surgery, her neuropsychiatric symptoms persisted, and she recovered slowly after the introduction of oral methotrexate (MTX). Sequential cerebral blood flow monitoring with single-photon emission computed tomography showed marked cerebellar hypoperfusion. Although mild impairments including working memory and verbal fluency persisted, she eventually returned to high school 3 years after onset. Profound cerebellar hypoperfusion including lobules VI and VII may be the reason for her working memory impairment and speaking problems. Oral MTX may be a promising alternative treatment for some refractory cases of anti-NMDAR encephalitis.

scholarly journals Independent and combined impact of hypoxia and acute inorganic nitrate ingestion on thermoregulatory responses to the cold

2021 ◽  
Vol 121 (4) ◽  
pp. 1207-1218
Author(s):  
Josh T. Arnold ◽  
Stephen J. Bailey ◽  
Simon G. Hodder ◽  
Naoto Fujii ◽  
Alex B. Lloyd
Keyword(s):  
Blood Flow ◽  
Cooling Rate ◽  
Skin Blood Flow ◽  
Rectal Temperature ◽  
Onset Time ◽  
Rate Of Change ◽  
Vascular Control ◽  
Delta Change ◽  
Core Cooling ◽  
The Impact

Abstract Purpose This study assessed the impact of normobaric hypoxia and acute nitrate ingestion on shivering thermogenesis, cutaneous vascular control, and thermometrics in response to cold stress. Method Eleven male volunteers underwent passive cooling at 10 °C air temperature across four conditions: (1) normoxia with placebo ingestion, (2) hypoxia (0.130 FiO2) with placebo ingestion, (3) normoxia with 13 mmol nitrate ingestion, and (4) hypoxia with nitrate ingestion. Physiological metrics were assessed as a rate of change over 45 min to determine heat loss, and at the point of shivering onset to determine the thermogenic thermoeffector threshold. Result Independently, hypoxia expedited shivering onset time (p = 0.05) due to a faster cooling rate as opposed to a change in central thermoeffector thresholds. Specifically, compared to normoxia, hypoxia increased skin blood flow (p = 0.02), leading to an increased core-cooling rate (p = 0.04) and delta change in rectal temperature (p = 0.03) over 45 min, yet the same rectal temperature at shivering onset (p = 0.9). Independently, nitrate ingestion delayed shivering onset time (p = 0.01), mediated by a change in central thermoeffector thresholds, independent of changes in peripheral heat exchange. Specifically, compared to placebo ingestion, no difference was observed in skin blood flow (p = 0.5), core-cooling rate (p = 0.5), or delta change in rectal temperature (p = 0.7) over 45 min, while nitrate reduced rectal temperature at shivering onset (p = 0.04). No interaction was observed between hypoxia and nitrate ingestion. Conclusion These data improve our understanding of how hypoxia and nitric oxide modulate cold thermoregulation.

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