Combined multi-distance frequency domain and diffuse correlation spectroscopy system with simultaneous data acquisition and real-time analysis

Carp, Stefan A.; Farzam, Parisa; Redes, Norin; Hueber, Dennis M.; Franceschini, Maria Angela

doi:10.1364/boe.8.003993

Cited by 65 publications

(74 citation statements)

References 45 publications

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“…Figure 7(d) shows D B determined from Eq. (S8), in two independent experiments, as well as the fit of the Einstein–Stokes equation, assuming the temperature dependence of water viscosity [33,34]. An average Intralipid particle radius of 171.8 ± 0.4 nm is estimated, in agreement with the previously reported value of 196 nm [33].…”

Section: Resultssupporting

confidence: 86%

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Highly parallel, interferometric diffusing wave spectroscopy for monitoring cerebral blood flow dynamics

Zhou

Kholiqov

Chong

et al. 2018

Optica

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Light-scattering methods are widely used in soft matter physics and biomedical optics to probe dynamics in turbid media, such as diffusion in colloids or blood flow in biological tissue. These methods typically rely on fluctuations of coherent light intensity, and therefore cannot accommodate more than a few modes per detector. This limitation has hindered efforts to measure deep tissue blood flow with high speed, since weak diffuse light fluxes, together with low single-mode fiber throughput, result in low photon count rates. To solve this, we introduce multimode fiber (MMF) interferometry to the field of diffuse optics. In doing so, we transform a standard complementary metal-oxide-semiconductor (CMOS) camera into a sensitive detector array for weak light fluxes that probe deep in biological tissue. Specifically, we build a novel CMOS-based, multimode interferometric diffusing wave spectroscopy (iDWS) system and show that it can measure ∼20 speckles simultaneously near the shot noise limit, acting essentially as ∼20 independent photon-counting channels. We develop a matrix formalism, based on MMF mode field solutions and detector geometry, to predict both coherence and speckle number in iDWS. After validation in liquid phantoms, we demonstrate iDWS pulsatile blood flow measurements at 2.5 cm source-detector separation in the adult human brain in vivo. By achieving highly sensitive and parallel measurements of coherent light fluctuations with a CMOS camera, this work promises to enhance performance and reduce cost of diffuse optical instruments.

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Section: Resultssupporting

confidence: 86%

“…Taking advantage of the parallel multispeckle detection of our iDWS system, we monitored high-speed pulsatile blood flow dynamics in the human brain in vivo [18,19,34,35]. A healthy adult human subject sat on a chair with her head placed on a chin rest.…”

Section: Resultsmentioning

confidence: 99%

Highly parallel, interferometric diffusing wave spectroscopy for monitoring cerebral blood flow dynamics

Zhou

Kholiqov

Chong

et al. 2018

Optica

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“…The details of the system and data analysis are described by Carp et al. (). For this work, we only considered the FDNIRS data even though DCS data were also acquired.…”

Section: Methodsmentioning

confidence: 99%

Validation of a novel wearable, wireless technology to estimate oxygen levels and lactate threshold power in the exercising muscle

2018

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There is a growing interest in monitoring muscle oxygen saturation (SmO2), which is a localized measure of muscle oxidative metabolism and can be acquired continuously and noninvasively using near‐infrared spectroscopy (NIRS) methods. Most NIRS systems are cumbersome, expensive, fiber coupled devices, with use limited to lab settings. A novel, low cost, wireless, wearable has been developed for use in athletic training. In this study, we evaluate the advantages and limitations of this new simple continuous‐wave (CW) NIRS device with respect to a benchtop, frequency‐domain near‐infrared spectroscopy (FDNIRS) system. Oxygen saturation and hemoglobin/myoglobin concentration in the exercising muscles of 17 athletic individuals were measured simultaneously with the two systems, while subjects performed an incremental test on a stationary cycle ergometer. In addition, blood lactate concentration was measured at the end of each increment with a lactate analyzer. During exercise, the correlation coefficients of the SmO2 and hemoglobin/myoglobin concentrations between the two systems were over 0.70. We also found both systems were insensitive to the presence of thin layers of varying absorption, mimicking different skin colors. Neither system was able to predict the athletes’ lactate threshold power accurately by simply using SmO2 thresholds. Instead, the proprietary software of the wearable device was able to predict the athletes’ lactate threshold power within half of one power increment of the cycling test. These results indicate this novel wearable device may provide a physiological indicator of athlete's exertion.

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“…; Carp et al . ; Hammer et al . ); however, none of these prior investigations have directly compared NIRS–DCS to conventional Fick determinants of oxygen delivery (i.e.…”

Section: Introductionmentioning

confidence: 99%

“…Diffuse correlation spectroscopy (DCS) is emerging as a powerful new tool to assess skeletal muscle perfusion (Gurley et al 2012;Henry et al 2015;Baker et al 2017;Carp et al 2017;Shang et al 2017;Bangalore-Yogananda et al 2018;Hammer et al 2018). DCS is completely non-invasive, has excellent temporal resolution (Bi et al 2015) and has been validated in a variety of organs and tissues against several different standards, including laser Doppler (Shang et al 2011), xenon-CT (Kim et al 2014), fluorescent microsphere flow measurements (Zhou et al 2009) and arterial spin labelled-MRI (Yu et al 2007).…”

Section: Introductionmentioning

confidence: 99%

Studies into the determinants of skeletal muscle oxygen consumption: novel insight from near‐infrared diffuse correlation spectroscopy

Tucker

Rosenberry

Trojacek

et al. 2019

The Journal of Physiology

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Key points Diffuse correlation spectroscopy (DCS) is emerging as a powerful tool to assess skeletal muscle perfusion. Near‐infrared spectroscopy (NIRS) is an established technique for characterizing the transport and utilization of oxygen through the microcirculation. Here we compared a combined NIRS–DCS system with conventional measures of oxygen delivery and utilization during handgrip exercise. The data show good concurrent validity between convective oxygen delivery and DCS‐derived blood flow index, as well as between oxygen extraction at the conduit and microvascular level. We then manipulated forearm arterial perfusion pressure by adjusting the position of the exercising arm relative to the position of the heart. The data show that microvascular perfusion can be uncoupled from convective oxygen delivery, and that tissue saturation seemingly compensates to maintain skeletal muscle oxygen consumption. Taken together, these data support a novel role for NIRS–DCS in understanding the determinants of muscle oxygen consumption at the microvascular level. Abstract Diffuse correlation spectroscopy (DCS) is emerging as a powerful tool to assess skeletal muscle perfusion. Combining DCS with near‐infrared spectroscopy (NIRS) introduces exciting possibilities for understanding the determinants of muscle oxygen consumption; however, no investigation has directly compared NIRS–DCS to conventional measures of oxygen delivery and utilization in an exercising limb. To address this knowledge gap, nine healthy males performed rhythmic handgrip exercise with simultaneous measurements by NIRS–DCS, Doppler blood flow and venous oxygen content. The two approaches showed good concurrent validity, with directionally similar responses between: (a) Doppler‐derived forearm blood flow and DCS‐derived blood flow index (BFI), and (b) venous oxygen saturation and NIRS‐derived tissue saturation. To explore the utility of combined NIRS–DCS across the physiological spectrum, we manipulated forearm arterial perfusion pressure by altering the arm position above or below the level of the heart. As expected, Doppler‐derived skeletal muscle blood flow increased with exercise in both arm positions, but with markedly different magnitudes (below: +424.3 ± 41.4 ml/min, above: +306 ± 12.0 ml/min, P = 0.002). In contrast, DCS‐derived microvascular BFI increased to a similar extent with exercise, regardless of arm position (P = 0.65). Importantly, however, the time to reach BFI steady state was markedly slower with the arm above the heart, supporting the experimental design. Notably, we observed faster tissue desaturation at the onset of exercise with the arm above the heart, resulting in similar muscle oxygen consumption profiles throughout exercise. Taken together, these data support a novel role for NIRS–DCS in understanding the determinants of skeletal muscle oxygen utilization non‐invasively and throughout exercise.

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Combined multi-distance frequency domain and diffuse correlation spectroscopy system with simultaneous data acquisition and real-time analysis

Cited by 65 publications

References 45 publications

Highly parallel, interferometric diffusing wave spectroscopy for monitoring cerebral blood flow dynamics

Highly parallel, interferometric diffusing wave spectroscopy for monitoring cerebral blood flow dynamics

Validation of a novel wearable, wireless technology to estimate oxygen levels and lactate threshold power in the exercising muscle

Studies into the determinants of skeletal muscle oxygen consumption: novel insight from near‐infrared diffuse correlation spectroscopy

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