Measuring human cerebral blood flow and brain function with fiber-based speckle contrast optical spectroscopy system

Communications Biology, Journal Year: 2023, Volume and Issue: 6(1)

Published: Aug. 14, 2023

Abstract Cerebral blood flow (CBF) is crucial for brain health. Speckle contrast optical spectroscopy (SCOS) a technique that has been recently developed to measure CBF, but the use of SCOS human function at large source-detector separations with comparable or greater sensitivity cerebral rather than extracerebral not demonstrated. We describe fiber-based system capable measuring activation induced CBF changes 33 mm source detector using CMOS detectors. The implements pulsing strategy improve photon flux and uses data processing pipeline measurement accuracy. show outperforms current leading modality i.e. diffuse correlation (DCS), achieving more 10x SNR improvement similar financial cost. Fiber-based provides an alternative approach functional neuroimaging cognitive neuroscience health science applications.

Language: Английский

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Comparing the performance potential of speckle contrast optical spectroscopy and diffuse correlation spectroscopy for cerebral blood flow monitoring using Monte Carlo simulations in realistic head geometries

Neurophotonics, Journal Year: 2024, Volume and Issue: 11(01)

Published: Jan. 27, 2024

SignificanceThe non-invasive measurement of cerebral blood flow based on diffuse optical techniques has seen increased interest as a research tool for perfusion monitoring in critical care and functional brain imaging. Diffuse correlation spectroscopy (DCS) speckle contrast (SCOS) are two such that measure complementary aspects the fluctuating intensity signal, with DCS quantifying temporal fluctuations signal SCOS spatial blurring pattern. With increasing use these techniques, thorough comparison would inform new adopters benefits each technique.AimWe systematically evaluate performance flow.ApproachMonte Carlo simulations dynamic light scattering an MRI-derived head model were performed. For both SCOS, estimates sensitivity to changes, coefficient variation measured flow, contrast-to-noise ratio calculated. By varying data collection between methods, we investigated different strategies, including altering number modes per detector, integration time/fitting time measurement, laser source delivery strategy.ResultsThrough across metrics simulated detectors having realistic noise properties, determine several guiding principles optimization report over range properties tissue geometries. We find outperforms terms ideal case here but note requires careful experimental calibrations ensure accurate measurements flow.ConclusionWe provide design by which development systems their flow.

Language: Английский

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Diffuse Correlation Spectroscopy: A Review of Recent Advances in Parallelisation and Depth Discrimination Techniques

Sensors, Journal Year: 2023, Volume and Issue: 23(23), P. 9338 - 9338

Published: Nov. 22, 2023

Diffuse correlation spectroscopy is a non-invasive optical modality used to measure cerebral blood flow in real time, and it has important potential applications clinical monitoring neuroscience. As such, many research groups have recently been investigating methods improve the signal-to-noise ratio, imaging depth, spatial resolution of diffuse spectroscopy. Such included multispeckle, long wavelength, interferometric, depth discrimination, time-of-flight resolution, acousto-optic detection strategies. In this review, we exhaustively appraise plethora recent advances, which can be assess limitations guide innovation for future implementations that will harness technological improvements years come.

Language: Английский

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Modified Beer-Lambert algorithm to measure pulsatile blood flow, critical closing pressure, and intracranial hypertension

Biomedical Optics Express, Journal Year: 2024, Volume and Issue: 15(9), P. 5511 - 5511

Published: Aug. 13, 2024

We introduce a frequency-domain modified Beer-Lambert algorithm for diffuse correlation spectroscopy to non-invasively measure flow pulsatility and thus critical closing pressure (CrCP). Using the same optical measurements, CrCP was obtained with new traditional nonlinear diffusion fitting. Results were compared invasive determination of intracranial (ICP) in piglets (n = 18). The better predicted ICP elevations; area under curve (AUC) from logistic regression analysis 0.85 ≥ 20 mmHg. corresponding AUC 0.60. Improved diagnostic performance likely results filtering extra-cerebral tissue contamination measurement noise.

Language: Английский

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scatterBrains: an open database of human head models and companion optode locations for realistic Monte Carlo photon simulations

Journal of Biomedical Optics, Journal Year: 2023, Volume and Issue: 28(10)

Published: Oct. 5, 2023

SignificanceMonte Carlo (MC) simulations are currently the gold standard in near-infrared and diffuse correlation spectroscopy (NIRS/DCS) communities for generating light transport paths through tissue. However, realistic diverse models that capture complex tissue layers not easily available to all; moreover, manually placing optodes on such can be tedious time consuming. Such limitations may hinder adoption of representative basic use these large-scale simulations, e.g., training machine learning algorithms.AimWe aim provide NIRS/DCS with an open-source, user-friendly database morphologically optically head models, as well a succinct software pipeline prepare mesh-based Monte transport.ApproachSixteen anatomical were created from segmented T1-weighted magnetic resonance imaging (MRI) scans converted tetrahedral mesh volumes. Approximately 800 companion scalp surface locations distributed each model, comprising full coverage. A was place custom source optical detectors at location, guidance is provided how parameters set up MC simulations.ResultsThe locations, all associated code freely under scatterBrains project Github.ConclusionsThe community benefits having shared resources conducting geometries. We hope this will make MRI-based virtual optode placement accessible all. Contributions welcome encouraged.

Language: Английский

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Comparison of diffuse correlation spectroscopy analytical models for measuring cerebral blood flow in adults

Journal of Biomedical Optics, Journal Year: 2023, Volume and Issue: 28(12)

Published: Dec. 15, 2023

SignificanceAlthough multilayer analytical models have been proposed to enhance brain sensitivity of diffuse correlation spectroscopy (DCS) measurements cerebral blood flow, the traditional homogeneous model remains dominant in clinical applications. Rigorous vivo comparison these is lacking.AimWe compare performance different estimate a flow index (CBFi) with DCS adults.ApproachResting-state data were obtained on cohort 20 adult patients subarachnoid hemorrhage. Data at 1 and 2.5 cm source-detector separations analyzed homogenous, two-layer, three-layer scalp CBFi. The each was quantified via fitting convergence, fit stability, brain-to-scalp ratio (BSR), transcranial Doppler ultrasound (TCD) velocity middle artery (MCA).ResultsThe has highest pass rate (100%), lowest coefficient variation (CV) rest (median [IQR] Hz 0.18 [0.13, 0.22]), most significant MCA velocities (Rs = 0.59, p 0.010) compared both two- models. significantly correlated extracerebral layer thicknesses. Discarding datasets non-physiological BSRs increased between measured CBFi TCD for all models.ConclusionsWe found that rate, CV rest, velocities. Results from should be taken caution because they suffer lower rates higher coefficients can converge values Future work needed validate vivo, novel approaches are merited improve multimodel

Language: Английский

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Validation of Diffuse Correlation Spectroscopy measurements of cerebral blood flow against perfusion MRI in adults

Published: Jan. 1, 2024

We quantify the accuracy of cerebral blood flow measurements diffuse correlation spectroscopy estimated with different analytical models by comparing against arterial spin labeled perfusion MRI.

Language: Английский

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