Relationship Between Signals from Cerebral near Infrared Spectroscopy Sensor Technology and Objectively Measured Cerebral Blood Volume: A Systematic Scoping Review

Sensors, Journal Year: 2025, Volume and Issue: 25(3), P. 908 - 908

Published: Feb. 3, 2025

Cerebral blood volume (CBV) is an essential metric that indicates and evaluates various healthy pathologic conditions. Most methods of CBV measurement are cumbersome have a poor temporal resolution. Recently, it has been proposed signals derived metrics from cerebral near-infrared spectroscopy (NIRS), non-invasive sensor, can be used to estimate CBV. However, this association remains vastly unexplored. As such, scoping review aimed examine the literature on relationship between NIRS A search six databases was conducted conforming Preferred Reporting Items for Systematic Reviews Meta-Analyses guidelines assess following question: What associations CBV? The database yielded 3350 unique results. Seven these articles were included in based inclusion exclusion criteria. An additional study identified while examining articles’ reference sections. Overall, systematic shows extreme variation CBV, with few sources objectively documenting true statistical two. This highlights current critical knowledge gap emphasizes need further research area.

Language: Английский

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Direct 3-D printing of complex optical phantoms using dynamic filament mixing

Scientific Reports, Journal Year: 2025, Volume and Issue: 15(1)

Published: March 21, 2025

We report a method to directly 3-D print complex heterogeneous optical phantoms with programmable tissue-mimicking absorption and scattering properties. The proposed approach utilizes commercially available multi-color mixing extruders off-the-shelf polylactic acid filaments, making this technique low-cost broadly accessible. systematically characterized properties, including both reduced coefficients, at wide range of ratios gray, white, translucent filaments validated our hypothesis linear-mixing model between the filament resulting Various techniques were used design fabricate sophisticated solid phantoms, color-purging towers, optimization several printing parameters improve quality. To demonstrate feasibility for generating anatomically tunable properties within tissue-relevant ranges, we designed fabricated three phantoms. One presented was specifically support quality assurance efforts in evaluating diffuse optics instruments methodologies across various institutions. have printed observed an average error 12%–15% compared model-predicted values. Future studies will target usage additional materials expand potential imaging applications.

Language: Английский

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Using depth-enhanced diffuse correlation spectroscopy and near-infrared spectroscopy to isolate cerebral hemodynamics during transient hypotension

Neurophotonics, Journal Year: 2023, Volume and Issue: 10(02)

Published: June 5, 2023

Combining diffuse correlation spectroscopy (DCS) and near-infrared (NIRS) permits simultaneous monitoring of multiple cerebral hemodynamic parameters related to autoregulation; however, interpreting these optical measurements can be confounded by signal contamination from extracerebral tissue.We aimed evaluate in NIRS/DCS data acquired during transient hypotension assess suitable means separating scalp brain signals.A hybrid time-resolved NIRS/multidistance DCS system was used simultaneously acquire oxygenation blood flow orthostatic induced rapid-onset lower body negative pressure (LBNP) nine young, healthy adults. Changes microvascular were verified against changes middle artery velocity (MCAv) measured transcranial Doppler ultrasound.LBNP significantly decreased arterial (-18%±14%), (>30%), tissue (all p≤0.04 versus baseline). However, implementing depth-sensitive techniques for both NIRS indicated that LBNP did not alter relative their baseline values p≥0.14). In agreement, there no significant reduction MCAv (8%±16%; p=0.09).Transient caused larger the compared brain. We demonstrate importance accounting within measures hemodynamics physiological paradigms designed test autoregulation.

Language: Английский

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Enhancing Transcranial Blood Flow Visualization with Dynamic Light Scattering Technologies: Advances in Quantitative Analysis

Laser & Photonics Review, Journal Year: 2024, Volume and Issue: unknown

Published: Sept. 20, 2024

Abstract A comparative application of major dynamic light scattering (DLS)‐based image methodologies applied to transcranial cerebral blood flow imaging is presented. In particular, the study delves into assessing capability Laser Doppler Flowmetry (LDF), Speckle Contrast Imaging (LSCI), and Diffuse Correlation Spectroscopy (DCS) in enhancing spatial temporal resolution imaging. An integral part focused on modulation through administration vasodilator drug, Sodium Nitroprusside (SNP). This pharmacological intervention facilitated a direct observation vasculature's responsiveness external stimuli, illuminating physiological adaptations within brain's microvascular architecture. Advanced LSCI processing techniques are incorporated, notably entropy principal component analysis (PCA). Entropy providing quantifiable measure randomness complexity speckle patterns images, revealing remarkably similar outcomes with DSC approach terms dynamics its quantitative evaluation. The PCA provided more nuanced understanding dynamics, facilitating identification subtle changes induced by drug administration. method proved instrumental visualization detection thereby allowing for detailed examination circulation alterations SNP seeks offer wider‐ranging insight comprehending translating further concept DLS transcrainial vizualization explore practical applications, considering hardware, advanced processing, data acquisition.

Language: Английский

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Special Section Guest Editorial: Thirty Years of Functional Near-Infrared Spectroscopy

Neurophotonics, Journal Year: 2023, Volume and Issue: 10(02)

Published: July 6, 2023

Functional Near-Infrared Spectroscopy (fNIRS) is a non-invasive optical technique that measures cerebral hemodynamics across multiple regions of interest, and thereby characterises brain functional activation. Since its first description in 1993, fNIRS has undergone substantial developments hardware, analysis techniques, applications. Thirty years later, this significantly enchancing our understanding diverse areas neuroscience research such as neurodevelopment, cognitive neuroscience, psychiatric disorders, neurodegenerative conditions, injury management intensive care settings. This special issue outlines the latest progress instrumentation techniques showcases some applications within expanding field over past decade.

Language: Английский

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ATLAS: a large array, on-chip compute SPAD camera for multispeckle diffuse correlation spectroscopy

Biomedical Optics Express, Journal Year: 2024, Volume and Issue: 15(11), P. 6499 - 6499

Published: Sept. 2, 2024

We present ATLAS, a 512 × single-photon avalanche diode (SPAD) array with embedded autocorrelation computation, implemented in 3D-stacked CMOS technology, suitable for correlation spectroscopy applications, including diffuse (DCS). The shared per-macropixel SRAM architecture provides 128 macropixel resolution, parallel minimum lag-time of 1 µs. demonstrate the direct, on-chip computation function sensor, and its capability to resolve changes decorrelation times typical body tissue real time, at long source-detector separations similar those achieved by current leading optical modalities cerebral blood flow monitoring. Finally, we suitability in-vivo measurements through cuff-occlusion forehead cardiac signal measurements.

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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Pathlength-selective, interferometric diffuse correlation spectroscopy (PaLS-iDCS)

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2024, Volume and Issue: unknown

Published: June 27, 2024

Diffuse correlation spectroscopy (DCS) is an optical method that offers non-invasive assessment of blood flow in tissue through the analysis intensity fluctuations diffusely backscattered coherent light. The nature technique has enabled several clinical applications for deep measurements, including cerebral monitoring as well tumor mapping. While a promising technique, measurement configurations targeting hemodynamics, standard DCS implementations suffer from insufficient signal-to-noise ratio (SNR), depth sensitivity, and sampling rate, limiting their utility. In this work, we present enhanced called pathlength-selective, interferometric (PaLS-iDCS), which improves upon both sensitivity to hemodynamics SNR using pathlength-specific gain. Through detection, PaLS-iDCS can provide time-of-flight (ToF) specific information without use expensive time-tagging electronics low-jitter detectors. new compared time-domain (TD-DCS), another able resolve photon ToF tissue, Monte Carlo simulation, phantom experiments, human subject measurements. consistently demonstrates improvements (>2x) similar conditions (same ToF), allow measurements at extended ToFs, have increased (~50% increase). Further, like TD-DCS, allows direct estimation properties sampled distribution need separate spectroscopic measurement. This relatively straightforward way systems make robust with greatly enabling further technology.

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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A 512×512 SPAD Laser Speckle Autocorrelation Imager in Stacked 65/40nm CMOS

2022 IEEE Symposium on VLSI Technology and Circuits (VLSI Technology and Circuits), Journal Year: 2024, Volume and Issue: unknown, P. 1 - 2

Published: June 16, 2024

Language: Английский

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