scholarly journals Experimental Validation of Microvasculature Blood Flow Modeling by Diffuse Correlation Spectroscopy

IEEE Access ◽  
2020 ◽  
Vol 8 ◽  
pp. 15945-15951
Author(s):  
Yanwen Zhu ◽  
Zhiguo Gui ◽  
Bing Xue ◽  
Yu Shang
Keyword(s):  
Blood Flow ◽  
Experimental Validation ◽  
Correlation Spectroscopy ◽  
Flow Modeling ◽  
Diffuse Correlation Spectroscopy ◽  
Blood Flow Modeling

scholarly journals Evaluation of Local Skeletal Muscle Blood Flow in Manipulative Therapy by Diffuse Correlation Spectroscopy

2022 ◽  
Vol 9 ◽  
Author(s):  
Yasuhiro Matsuda ◽  
Mikie Nakabayashi ◽  
Tatsuya Suzuki ◽  
Sinan Zhang ◽  
Masashi Ichinose ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Skeletal Muscle ◽  
Blood Flow ◽  
Muscle Blood Flow ◽  
Nervous Activity ◽  
Correlation Spectroscopy ◽  
Autonomic Nervous Activity ◽  
Local Blood Flow ◽  
Diffuse Correlation Spectroscopy ◽  
Manipulative Therapy

Manipulative therapy (MT) is applied to motor organs through a therapist’s hands. Although MT has been utilized in various medical treatments based on its potential role for increasing the blood flow to the local muscle, a quantitative validation of local muscle blood flow in MT remains challenging due to the lack of appropriate bedside evaluation techniques. Therefore, we investigated changes in the local blood flow to the muscle undergoing MT by employing diffuse correlation spectroscopy, a portable and emerging optical measurement technology that non-invasively measures blood flow in deep tissues. This study investigated the changes in blood flow, heart rate, blood pressure, and autonomic nervous activity in the trapezius muscle through MT application in 30 volunteers without neck and shoulder injury. Five minutes of MT significantly increased the median local blood flow relative to that of the pre-MT period (p < 0.05). The post-MT local blood flow increase was significantly higher in the MT condition than in the control condition, where participants remained still without receiving MT for the same time (p < 0.05). However, MT did not affect the heart rate, blood pressure, or cardiac autonomic nervous activity. The post-MT increase in muscle blood flow was significantly higher in the participants with muscle stiffness in the neck and shoulder regions than in those without (p < 0.05). These results suggest that MT could increase the local blood flow to the target skeletal muscle, with minimal effects on systemic circulatory function.

Impact of Changes in Tissue Optical Properties on Near-Infrared Diffuse Correlation Spectroscopy Measures of Skeletal Muscle Blood Flow

2021 ◽  
Author(s):  
Miles F. Bartlett ◽  
Scott M. Jordan ◽  
Dennis M. Hueber ◽  
Michael D. Nelson
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Optical Properties ◽  
Near Infrared ◽  
Muscle Blood Flow ◽  
Reactive Hyperemia ◽  
Correlation Spectroscopy ◽  
Skeletal Muscle Blood Flow ◽  
Diffuse Correlation Spectroscopy ◽  
Tissue Optical Properties

Near-infrared diffuse correlation spectroscopy (DCS) is increasingly utilized to study relative changes in skeletal muscle blood flow. However, most diffuse correlation spectrometers assume that tissue optical properties- such as absorption (μa) and reduced scattering (μ's) coefficients- remain constant during physiological provocations, which is untrue for skeletal muscle. Here, we interrogate how changes in tissue μa and μ's affect DCS calculations of blood flow index (BFI). We recalculated BFI using raw autocorrelation curves and μa/μ's values recorded during a reactive hyperemia protocol in 16 healthy young individuals. First, we show that incorrectly assuming baseline μa and μ's substantially affects peak BFI and BFI slope when expressed in absolute terms (cm2/s, p<0.01) but these differences are abolished when expressed in relative terms (% baseline). Next, to evaluate the impact of physiologic changes in μa and μ's, we compared peak BFI and BFI slope when μa and μ's were held constant throughout the reactive hyperemia protocol versus integrated from a 3s-rolling average. Regardless of approach, group means for peak BFI and BFI slope did not differ. Group means for peak BFI and BFI slope were also similar following ad absurdum analyses, where we simulated supraphysiologic changes in μa/μ's. In both cases, however, we identified individual cases where peak BFI and BFI slope were indeed affected, with this result being driven by relative changes in μa over μ's. Overall, these results provide support for past reports in which μa/μ's were held constant but also advocate for real-time incorporation of μa and μ's moving forward.

Abstract 16856: Mathematical Modeling of Blood Flow to Evaluate the Hemodynamic Significance of Peripheral Vascular Lesions

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Seyed Mehran Mirramezani ◽  
Paul Cimadomo ◽  
Ernie Ahsan ◽  
David Shavelle ◽  
Leonardo Clavijo ◽  
...  
Keyword(s):  
Blood Flow ◽  
Pressure Gradient ◽  
Ankle Brachial Index ◽  
Peripheral Arteries ◽  
Flow Modeling ◽  
Peripheral Vascular ◽  
Blood Flow Modeling ◽  
Resting Pressure ◽  
Grade Iii ◽  
Significant Lesion

Introduction: Evaluating the severity of lesions in peripheral arteries is challenging. Image-based blood flow modeling from peripheral computed tomographic angiography (pCTA) may provide a non-invasive method to determine the hemodynamic significance of lesions. The objective of this study was to evaluate the diagnostic performance of a trans-lesion pressure drop computed from pCTA-based blood flow modeling in the peripheral arteries. Methods: Ten patients undergoing digital subtraction angiography (DSA) and pCTA were included. The peripheral arteries were divided into 8 segments per extremity and stenosis severity was visually graded by DSA as non-stenosed (grade 0), mild (grade I), moderate (grade II), severe (grade III), occluded (grade IV) or non-evaluable. A functionally significant lesion was defined as grade III or IV by DSA. Independent from the DSA review, a resting pressure gradient (rPG) and exercise PG (ExPG) for each segment was calculated from pCTA-based blood flow modeling (Figure), and a functionally significant lesion was defined as having an rPG > 5 mm Hg or an ExPG > 20 mm Hg. Results: Mean age was 52±16 years, 4 patients (40%) were male, 8 patients (80%) presented with critical limb ischemia, mean ankle brachial index was 0.60±0.29 and 66 arterial segments were available for both assessment methods. Twenty-two segments had functionally significant lesions by DSA. For rPG, sensitivity was 80%, specificity was 85% and accuracy was 79% with DSA as the standard; for ExPG, sensitivity was 84%, specificity was 89% and accuracy was 88%. Conclusions: Use of a resting pressure gradient > 5 mm Hg and an exercise pressure gradient > 20 mm Hg measured by peripheral computed tomography-based blood flow modeling accurately identifies functionally significant stenosis in patients with advanced peripheral vascular disease. These results support a prospective imaging trial to further validate this novel approach.

Cerebral Blood Flow of the Neonatal Brain after Hypoxic-Ischemic Injury

2021 ◽  
Author(s):  
Luis Octavio Tierradentro-García ◽  
Sandra Saade-Lemus ◽  
Colbey Freeman ◽  
Matthew Kirschen ◽  
Hao Huang ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Near Infrared ◽  
Imaging Modality ◽  
Brain Perfusion ◽  
Correlation Spectroscopy ◽  
Therapeutic Interventions ◽  
Routine Practice ◽  
Diffuse Correlation Spectroscopy ◽  
Positron Emission

Objective Hypoxic-ischemic encephalopathy (HIE) in infants can have long-term adverse neurodevelopmental effects and markedly reduce quality of life. Both the initial hypoperfusion and the subsequent rapid reperfusion can cause deleterious effects in brain tissue. Cerebral blood flow (CBF) assessment in newborns with HIE can help detect abnormalities in brain perfusion to guide therapy and prognosticate patient outcomes. Study Design The review will provide an overview of the pathophysiological implications of CBF derangements in neonatal HIE, current and emerging techniques for CBF quantification, and the potential to utilize CBF as a physiologic target in managing neonates with acute HIE. Conclusion The alterations of CBF in infants during hypoxia-ischemia have been studied by using different neuroimaging techniques, including nitrous oxide and xenon clearance, transcranial Doppler ultrasonography, contrast-enhanced ultrasound, arterial spin labeling MRI, 18F-FDG positron emission tomography, near-infrared spectroscopy (NIRS), functional NIRS, and diffuse correlation spectroscopy. Consensus is lacking regarding the clinical significance of CBF estimations detected by these different modalities. Heterogeneity in the imaging modality used, regional versus global estimations of CBF, time for the scan, and variables impacting brain perfusion and cohort clinical characteristics should be considered when translating the findings described in the literature to routine practice and implementation of therapeutic interventions. Key Points

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