Multidistance diffuse correlation spectroscopy for simultaneous estimation of blood flow index and 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.

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Impact of errors in optical properties and/or geometry on the recovery of cerebral blood flow using diffuse correlation spectroscopy

Biomedical Optics 2016 ◽

10.1364/cancer.2016.jtu3a.20 ◽

2016 ◽

Author(s):

S.A. Carp ◽

D.A. Boas ◽

J. Selb

Keyword(s):

Blood Flow ◽

Optical Properties ◽

Cerebral Blood Flow ◽

Correlation Spectroscopy ◽

Diffuse Correlation Spectroscopy

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Near-infrared diffuse correlation spectroscopy tracks changes in oxygen delivery and utilization during exercise with and without isolated arterial compression

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00212.2019 ◽

2020 ◽

Vol 318 (1) ◽

pp. R81-R88

Author(s):

Wesley J. Tucker ◽

Ryan Rosenberry ◽

Darian Trojacek ◽

Belinda Sanchez ◽

Robert F. Bentley ◽

...

Keyword(s):

Skeletal Muscle ◽

Blood Flow ◽

Radial Artery ◽

Brachial Artery ◽

Oxygen Delivery ◽

Near Infrared ◽

Correlation Spectroscopy ◽

Flow Index ◽

Artery Blood Flow ◽

Diffuse Correlation Spectroscopy

Near-infrared diffuse correlation spectroscopy (NIR-DCS) is an emerging technology for simultaneous measurement of skeletal muscle microvascular oxygen delivery and utilization during exercise. The extent to which NIR-DCS can track acute changes in oxygen delivery and utilization has not yet been fully established. To address this knowledge gap, 14 healthy men performed rhythmic handgrip exercise at 30% maximal voluntary contraction, with and without isolated brachial artery compression, designed to acutely reduce convective oxygen delivery to the exercising muscle. Radial artery blood flow (Duplex Ultrasound) and NIR-DCS derived variables [blood flow index (BFI), tissue oxygen saturation ([Formula: see text]), and metabolic rate of oxygen ([Formula: see text])] were simultaneously measured. During exercise, both radial artery blood flow (+51.6 ± 20.3 mL/min) and DCS-derived BFI (+155.0 ± 82.2%) increased significantly ( P < 0.001), whereas [Formula: see text] decreased −7.9 ± 6.2% ( P = 0.002) from rest. Brachial artery compression during exercise caused a significant reduction in both radial artery blood flow (−32.0 ± 19.5 mL/min, P = 0.001) and DCS-derived BFI (−57.3 ± 51.1%, P = 0.01) and a further reduction of [Formula: see text] (−5.6 ± 3.8%, P = 0.001) compared with exercise without compression. [Formula: see text] was not significantly reduced during arterial compression ( P = 0.83) due to compensatory reductions in [Formula: see text], driven by increases in deoxyhemoglobin/myoglobin (+7.1 ± 6.1 μM, P = 0.01; an index of oxygen extraction). Together, these proof-of-concept data help to further validate NIR-DCS as an effective tool to assess the determinants of skeletal muscle oxygen consumption at the level of the microvasculature during exercise.

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Near-Infrared Spectroscopy Assessment of Cerebral Oxygen Metabolism in the Developing Premature Brain

Journal of Cerebral Blood Flow & Metabolism ◽

10.1038/jcbfm.2011.145 ◽

2011 ◽

Vol 32 (3) ◽

pp. 481-488 ◽

Cited By ~ 57

Author(s):

Nadège Roche-Labarbe ◽

Angela Fenoglio ◽

Alpna Aggarwal ◽

Mathieu Dehaes ◽

Stefan A Carp ◽

...

Keyword(s):

Blood Flow ◽

Cerebral Blood Flow ◽

Infrared Spectroscopy ◽

Near Infrared Spectroscopy ◽

Near Infrared ◽

Correlation Spectroscopy ◽

Chronological Age ◽

Flow Index ◽

P Value ◽

Blood Flow Index

Little is known about cerebral blood flow, cerebral blood volume (CBV), oxygenation, and oxygen consumption in the premature newborn brain. We combined quantitative frequency-domain near-infrared spectroscopy measures of cerebral hemoglobin oxygenation (SO2) and CBV with diffusion correlation spectroscopy measures of cerebral blood flow index (BFix) to determine the relationship between these measures, gestational age at birth (GA), and chronological age. We followed 56 neonates of various GA once a week during their hospital stay. We provide absolute values of SO2 and CBV, relative values of BFix, and relative cerebral metabolic rate of oxygen (rCMRO2) as a function of postmenstrual age (PMA) and chronological age for four GA groups. SO2 correlates with chronological age ( r=−0.54, P value 0.001) but not with PMA ( r=−0.07), whereas BFix and rCMRO2 correlate better with PMA ( r=0.37 and 0.43, respectively, P value 0.001). Relative CMRO2 during the first month of life is lower when GA is lower. Blood flow index and rCMRO2 are more accurate biomarkers of the brain development than SO2 in the premature newborns.

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Time-domain diffuse correlation spectroscopy (TD-DCS) for noninvasive, depth-dependent blood flow quantification in human tissue in vivo

Scientific Reports ◽

10.1038/s41598-021-81448-5 ◽

2021 ◽

Vol 11 (1) ◽

Cited By ~ 1

Author(s):

Saeed Samaei ◽

Piotr Sawosz ◽

Michał Kacprzak ◽

Żanna Pastuszak ◽

Dawid Borycki ◽

...

Keyword(s):

Blood Flow ◽

Time Domain ◽

Human Tissue ◽

Correlation Spectroscopy ◽

Flow Quantification ◽

Flow Index ◽

Flow Measurements ◽

Diffuse Correlation Spectroscopy ◽

Sensing Applications

AbstractMonitoring of human tissue hemodynamics is invaluable in clinics as the proper blood flow regulates cellular-level metabolism. Time-domain diffuse correlation spectroscopy (TD-DCS) enables noninvasive blood flow measurements by analyzing temporal intensity fluctuations of the scattered light. With time-of-flight (TOF) resolution, TD-DCS should decompose the blood flow at different sample depths. For example, in the human head, it allows us to distinguish blood flows in the scalp, skull, or cortex. However, the tissues are typically polydisperse. So photons with a similar TOF can be scattered from structures that move at different speeds. Here, we introduce a novel approach that takes this problem into account and allows us to quantify the TOF-resolved blood flow of human tissue accurately. We apply this approach to monitor the blood flow index in the human forearm in vivo during the cuff occlusion challenge. We detect depth-dependent reactive hyperemia. Finally, we applied a controllable pressure to the human forehead in vivo to demonstrate that our approach can separate superficial from the deep blood flow. Our results can be beneficial for neuroimaging sensing applications that require short interoptode separation.

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