Near-Infrared Diffuse Correlation Spectroscopy for Assessment of Tissue Blood Flow

2016 ◽  
pp. 215-236 ◽  
Keyword(s):  
Blood Flow ◽  
Near Infrared ◽  
Correlation Spectroscopy ◽  
Tissue Blood Flow ◽  
Diffuse Correlation Spectroscopy

scholarly journals Portable Near-Infrared Technologies and Devices for Noninvasive Assessment of Tissue Hemodynamics

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Lin Hou ◽  
Yinqiu Liu ◽  
Lixia Qian ◽  
Yucong Zheng ◽  
Jinnan Gao ◽  
...  
Keyword(s):  
Blood Flow ◽  
Flow Measurement ◽  
Near Infrared ◽  
Tissue Oxygenation ◽  
Oxygen Metabolism ◽  
Correlation Spectroscopy ◽  
Tissue Blood Flow ◽  
Diffuse Optical Spectroscopy ◽  
Diffuse Correlation Spectroscopy ◽  
Custom Made

Tissue hemodynamics, including the blood flow, oxygenation, and oxygen metabolism, are closely associated with many diseases. As one of the portable optical technologies to explore human physiology and assist in healthcare, near-infrared diffuse optical spectroscopy (NIRS) for tissue oxygenation measurement has been developed for four decades. In recent years, a dynamic NIRS technology, namely, diffuse correlation spectroscopy (DCS), has been emerging as a portable tool for tissue blood flow measurement. In this article, we briefly describe the basic principle and algorithms for static NIRS and dynamic NIRS (i.e., DCS). Then, we elaborate on the NIRS instrumentation, either commercially available or custom-made, as well as their applications to physiological studies and clinic. The extension of NIRS/DCS from spectroscopy to imaging was depicted, followed by introductions of advanced algorithms that were recently proposed. The future prospective of the NIRS/DCS and their feasibilities for routine utilization in hospital is finally discussed.

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.

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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