Assessment of myocardial blood flow by real-time infrared imaging

Adachi, Hideo; Becker, Lewis C.; Ambrosio, Giuseppe; Takeda, Kan; DiPaula, Anthony; Baumgartner, William A.; Borkon, A. Michael; Reitz, Bruce A.

doi:10.1016/0022-4804(87)90052-7

Cited by 27 publications

(22 citation statements)

References 6 publications

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“…10 The temperature measured on the tissue surface by means of IRT strongly correlates with the blood flow, and IRT is sensitive enough to quantify the effects of various levels of occlusion on the local organ perfusion. 1,28,38 Additional information on blood flow conditions in skeletal muscles can be provided by finite element (FE) simulations. For example, Vankan et al (1996) and van Donkelaar et al (2001) used FE to simulate perfusion in muscle tissue during tetanic, isometric contraction and maximal vasodilatation.…”

Section: Introductionmentioning

confidence: 99%

The Effects of Pressure and Shear on Capillary Closure in the Microstructure of Skeletal Muscles

2007

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Deep tissue injury (DTI) is a severe pressure ulcer, which initiates in muscle tissue under a bony prominence, and progresses outwards. It is associated with mechanical pressure and shear that may cause capillaries to collapse and thus, induce ischemic conditions. Recently, some investigators stipulated that ischemia alone cannot explain the etiology of DTI, and other mechanisms, particularly excessive cellular deformations may be involved. The goal of this study was to evaluate the functioning of capillaries in loaded muscle tissue, using animal and finite element (FE) models. Pressures of 12, 37, and 78 kPa were applied directly to one gracilis muscle of 11 rats for 2 h. Temperatures of the loaded and contralateral muscles were recorded with time using infrared thermography (IRT) as a measure of the ischemic level. In addition, a non-linear large deformation muscle-fascicle-level FE model was developed and subjected to pressures of 12-120 kPa without and with simultaneous shear strain of up to 8%. For each simulation case, the accumulative percentage of open capillary cross-sectional area and the number of completely closed capillaries were determined. After 2 h, temperature of the loaded muscles was 2.4 +/- 0.3 degrees C (mean +/- standard deviation) lower than that of the unloaded contralateral limbs (mean of plateau temperature values across all pressure groups). Temperature of the loaded muscles dropped within 10 min but then remained stable and significantly higher than room temperature for at least 30 additional minutes in all pressure groups, indicating that limbs were not completely ischemic within the first 40 min of the trials. Our FE model showed that in response to pressures of 12-120 kPa and no shear, the accumulative percentage of open capillary cross-sectional area decreased by up to 71%. When shear strains were added, the open capillary cross-sectional area decreased more rapidly, but even for maximal loading, only 46% of the capillaries were completely closed. Taken together, the animal and FE model results suggest that acute ischemia does not develop in skeletal muscles under physiological load levels within a timeframe of 40 min. Since there is evidence that DTI develops within a shorter time, ischemia is unlikely to be the only factor causing DTI.

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Section: Introductionmentioning

confidence: 99%

The Effects of Pressure and Shear on Capillary Closure in the Microstructure of Skeletal Muscles

2007

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“…Yet another non-invasive technique that provides epicardial flow distribution in the exposed heart setting is infrared (IR) thermal imaging since the heart surface temperature is mainly determined by coronary flow [5][6][7][8][9][10]. However, application of thermal imaging, which yields 2-dimensional temperature maps of the cardiac surface, revealed non-linear dependence of DT on coronary flow at high flows [9,11]. In other words, areas with moderate flow decreases from 100% to 50% could be overlooked in NIR and thermal images.…”

Section: Introductionmentioning

confidence: 99%

Detection of moderate regional ischemia in pig hearts in vivo by near-infrared and thermal imaging: effects of dipyridamole

Kupriyanov

Manley

Xiang

2007

Int J Cardiovasc Imaging

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Effects of coronary vasodilator, dipyridamole, on epicardial oxygenation and flow were investigated under conditions of moderate coronary occlusion using near-infrared spectroscopic (NIRS) and thermal imaging. In anesthetized open chest pigs an inflatable occluder and flow probe were placed around the left anterior descending artery (LAD). In the ischemic group (n = 11) LAD occlusion (50% flow, 80 min) was followed by complete occlusion (10 min, n = 4), and reflow. Dipyridamole was infused (0.14 mg/min/kg/4 min) intravenously during 50% occlusion. In the control group (n = 6) LAD flow was temporarily increased (hyperemic response) by two 2-min periods of complete LAD occlusion applied 120 min apart, with a 4-min period of dipyridamole infusion between the two occlusions. NIRS and thermal images were acquired throughout the protocol. Maps of subepicardial oxygen saturation parameter (OSP), and epicardial temperature (T) were obtained. Partial occlusion reduced OSP and the temperature by 0.23 +/- 0.08 and 0.88 +/- 0.39 degrees C versus remote region, respectively. Dipyridamole decreased systolic blood pressure by 36%, which caused further decline in the LAD flow to 18% and OSP and T by 0.37 +/- 0.01 and 2.46 +/- 0.32 degrees C, respectively. Reflow restored OSP and T to their baseline levels. In control group dipyridamole and hyperemia increased LAD flow 2-4-fold associated with moderate increase in OSP and T. OSP and T showed linear dependence on the flow below 100%, which is leveled-off at flows above normal. Dipyridamole increases differences in the epicardial oxygenation and T between normal and moderately ischemic areas due to enhancement of disparity in perfusion of these areas.

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“…In horses, IRT has been applied for the diagnosis of lameness, back pain/intervertebral disk problem, muscle tears/strain, tendonitis, fractures, neuritis and peritonitis [9]. In dogs, infrared thermography has been experimentally introduced to detect the cardiac ischemia, coronary artery attenuation and intestinal infarction [1,2,4]. IRT was used for the determination of a dosage regimen of nimesulide, a cyclooxygenase 2 selective non steroidal antiinflammatory drug in the dog [8].…”

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confidence: 99%

Thermographic Evaluation for the Efficacy of Acupuncture on Induced Chronic Arthritis in the Dog

Kim

Lim

et al. 2005

The Journal of Veterinary Medical Science

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ABSTRACT. This study was performed to evaluate the efficacy of acupuncture on induced chronic arthritis of the dog by thermography. Complete Freund's adjuvant was injected into the left knee joint of 8 dogs to induce arthritis. Acupuncture was applied to BL-40, GB-33, GB-34, and LIV-8 once a week for 4 consecutive weeks, from 3 weeks after induction of chronic arthritis, in treatment group. At 3 weeks of acupuncture treatment, skin temperature difference (∆T) of treatment group returned to normal range (< 0.3°C), while ∆T remained high in non-treatment group. Infrared thermography (IRT) is useful to evaluate the treatment of acupuncture for induced canine chronic arthritis. Therefore, it is considered that clinical application of IRT in arthritis treatment would be also valuable.

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Assessment of myocardial blood flow by real-time infrared imaging

Cited by 27 publications

References 6 publications

The Effects of Pressure and Shear on Capillary Closure in the Microstructure of Skeletal Muscles

The Effects of Pressure and Shear on Capillary Closure in the Microstructure of Skeletal Muscles

Detection of moderate regional ischemia in pig hearts in vivo by near-infrared and thermal imaging: effects of dipyridamole

Thermographic Evaluation for the Efficacy of Acupuncture on Induced Chronic Arthritis in the Dog

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