Improved accuracy of cerebral blood flow quantification in the presence of systemic physiology cross-talk using multi-layer Monte Carlo modeling DOI Creative Commons
Melissa M. Wu, Suk‐Tak Chan,

Dibbyan Mazumder

et al.

Neurophotonics, Journal Year: 2021, Volume and Issue: 8(01)

Published: Jan. 1, 2021

Significance: Contamination of diffuse correlation spectroscopy (DCS) measurements cerebral blood flow (CBF) due to systemic physiology remains a significant challenge in the clinical translation DCS for neuromonitoring. Tunable, multi-layer Monte Carlo-based (MC) light transport models have potential remove extracerebral cross-talk index ( CBFi ) estimates. Aim: We explore effectiveness MC recovering accurate changes presence strong variations during hypercapnia maneuver. Approach: Multi-layer slab and head-like realistic (curved) geometries were used run simulations photon propagation through head. The simulation data post-processed into with variable thicknesses fit multi-distance intensity autocorrelation estimate timecourses. results values from set human subject sessions compared estimated using semi-infinite analytical model, as commonly field. Results: Group averages indicate gradual increase following different temporal profile versus expected rapid CBF response. Optimized models, guided by several intrinsic criteria pressure modulation maneuver, able more effectively separate scalp influence than fitting, which assumed homogeneous medium. Three-layer performed better two-layer ones; curved achieved largely similar results, though closer physiological layer thicknesses. Conclusion: Three-layer, adjustable can be useful separating distinct brain flow. Pressure modulation, along reasonable estimates parameters, help direct choice appropriate models.

Language: Английский

Cerebral blood flow and autoregulation: current measurement techniques and prospects for noninvasive optical methods DOI Open Access
Sergio Fantini, Angelo Sassaroli,

Kristen Tgavalekos

et al.

Neurophotonics, Journal Year: 2016, Volume and Issue: 3(3), P. 031411 - 031411

Published: June 21, 2016

Cerebral blood flow (CBF) and cerebral autoregulation (CA) are critically important to maintain proper brain perfusion supply the with necessary oxygen energy substrates. Adequate is required support normal function, achieve successful aging, navigate acute chronic medical conditions. We review general principles of CBF measurements current techniques measure based on direct intravascular measurements, nuclear medicine, X-ray imaging, magnetic resonance ultrasound techniques, thermal diffusion, optical methods. also for arterial pressure as well theoretical experimental methods assessment CA, including recent approaches techniques. The in clinical practice presented. comprehensive description principles, methods, requirements CA highlights potentially role that noninvasive can play neurovascular health. In fact, have ability provide a noninvasive, quantitative, continuous monitor autoregulation.

Language: Английский

Citations

319
Modified Beer-Lambert law for blood flow DOI Creative Commons
Wesley B. Baker, Ashwin B. Parthasarathy, David R. Busch

et al.

Biomedical Optics Express, Journal Year: 2014, Volume and Issue: 5(11), P. 4053 - 4053

Published: Oct. 28, 2014

We develop and validate a Modified Beer-Lambert law for blood flow based on diffuse correlation spectroscopy (DCS) measurements.The new formulation enables monitoring from temporal intensity autocorrelation function data taken at single or multiple delay-times.Consequentially, the speed of optical measurement can be substantially increased.The scheme facilitates highly scattering tissues in geometries wherein light propagation is diffusive non-diffusive, it particularly well-suited utilization with pressure paradigms that employ differential signals to reduce contributions superficial tissues.

Language: Английский

Citations

234
Optical imaging and spectroscopy for the study of the human brain: status report DOI Creative Commons
Hasan Ayaz, Wesley B. Baker, Giles Blaney

et al.

Neurophotonics, Journal Year: 2022, Volume and Issue: 9(S2)

Published: Aug. 30, 2022

This report is the second part of a comprehensive two-part series aimed at reviewing an extensive and diverse toolkit novel methods to explore brain health function. While first focused on neurophotonic tools mostly applicable animal studies, here, we highlight optical spectroscopy imaging relevant noninvasive human studies. We outline current state-of-the-art technologies software advances, most recent impact these neuroscience clinical applications, identify areas where innovation needed, provide outlook for future directions.

Language: Английский

Citations

118
Fast blood flow monitoring in deep tissues with real-time software correlators DOI Creative Commons
Detian Wang, Ashwin B. Parthasarathy, Wesley B. Baker

et al.

Biomedical Optics Express, Journal Year: 2016, Volume and Issue: 7(3), P. 776 - 776

Published: Feb. 3, 2016

We introduce, validate and demonstrate a new software correlator for high-speed measurement of blood flow in deep tissues based on diffuse correlation spectroscopy (DCS).The scheme employs standard PC-based data acquisition boards to measure temporal intensity autocorrelation functions continuously at 50 -100 Hz, the fastest measurements reported with DCS date.The streams, obtained vivo typical source-detector separations 2.5 cm, easily resolve pulsatile heart-beat fluctuations which were previously considered be noise.We employ device separate tissue from absorption/scattering dynamics thereby show that origin signal is primarily flow, we monitor cerebral autoregulation healthy volunteers more accurately than traditional instrumentation as result increased rates.Finally, characterize signal-to-noise ratio identify count rate averaging parameters needed optimal performance.

Language: Английский

Citations

104
Simultaneous functional near-infrared spectroscopy and electroencephalography for monitoring of human brain activity and oxygenation: a review DOI Creative Commons
Antonio Maria Chiarelli, Filippo Zappasodi,

Francesco Pompeo

et al.

Neurophotonics, Journal Year: 2017, Volume and Issue: 4(04), P. 1 - 1

Published: Aug. 22, 2017

Multimodal monitoring has become particularly common in the study of human brain function. In this context, combined, synchronous measurements functional near-infrared spectroscopy (fNIRS) and electroencephalography (EEG) are getting increased interest. Because absence electro-optical interference, it is quite simple to integrate these two noninvasive recording procedures activity. fNIRS EEG both scalp-located procedures. estimates hemodynamic fluctuations relying on spectroscopic measurements, whereas captures macroscopic temporal dynamics electrical activity through passive voltages evaluations. The "orthogonal" neurophysiological information provided by technologies increasing interest neurovascular coupling phenomenon further encourage their integration. This review provides, together with an introduction regarding principles future directions technologies, evaluation major clinical nonclinical applications flexible, low-cost combination neuroimaging modalities. fNIRS–EEG systems exploit ability be conducted environment or experimental setting and/or subjects that generally not suited for other modalities, such as magnetic resonance imaging, positron emission tomography, magnetoencephalography. settles itself a useful multimodal tool investigation.

Language: Английский

Citations

100
Continuous non-invasive optical monitoring of cerebral blood flow and oxidative metabolism after acute brain injury DOI Open Access
Wesley B. Baker, Ramani Balu,

Lian He

et al.

Journal of Cerebral Blood Flow & Metabolism, Journal Year: 2019, Volume and Issue: 39(8), P. 1469 - 1485

Published: May 14, 2019

Rapid detection of ischemic conditions at the bedside can improve treatment acute brain injury. In this observational study 11 critically ill brain-injured adults, we employed a monitoring approach that interleaves time-resolved near-infrared spectroscopy (TR-NIRS) measurements cerebral oxygen saturation and extraction fraction (OEF) with diffuse correlation (DCS) measurement blood flow (CBF). Using approach, demonstrate clinical promise non-invasive, continuous optical changes in CBF metabolic rate (CMRO 2 ). addition, CMRO measures were compared to invasive tissue tension (PbtO ), thermal diffusion flowmetry CBF, microdialysis obtained concurrently. The information successfully distinguished between ischemic, hypermetabolic, hyperemic arose spontaneously during patient care. Moreover, pressor-induced mean arterial pressure enabled assessment autoregulation. total, findings suggest hybrid non-invasive neurometabolic monitor (NNOM) facilitate adverse physiological injured patients are otherwise difficult measure conventional techniques.

Language: Английский

Citations

79
Neonatal NIRS monitoring: recommendations for data capture and review of analytics DOI Open Access
Zachary A. Vesoulis,

Jonathan Mintzer,

Valerie Y. Chock

et al.

Journal of Perinatology, Journal Year: 2021, Volume and Issue: 41(4), P. 675 - 688

Published: Feb. 15, 2021

Language: Английский

Citations

61
Combined multi-distance frequency domain and diffuse correlation spectroscopy system with simultaneous data acquisition and real-time analysis DOI Creative Commons
Stefan A. Carp, Parisa Farzam,

Norin Redes

et al.

Biomedical Optics Express, Journal Year: 2017, Volume and Issue: 8(9), P. 3993 - 3993

Published: Aug. 7, 2017

Frequency domain near infrared spectroscopy (FD-NIRS) and diffuse correlation (DCS) have emerged as synergistic techniques for the non-invasive assessment of tissue health. Combining FD-NIRS oximetry with DCS measures blood flow, oxygen metabolic rate can be quantified, a parameter more closely linked to underlying physiology pathology than either NIRS or estimates alone. Here we describe first commercially available integrated instrument, called "MetaOx", designed enable simultaneous measurements at rates 10 + Hz, offering real-time data evaluation. We show simultaneously acquired characterization demonstrating performance equivalent individual devices sample in vivo pulsation resolved forearm occlusion hemodynamic changes muscle monitoring during stationary bike exercise.

Language: Английский

Citations

78
Pressure modulation algorithm to separate cerebral hemodynamic signals from extracerebral artifacts DOI Open Access
Wesley B. Baker, Ashwin B. Parthasarathy, Tiffany S. Ko

et al.

Neurophotonics, Journal Year: 2015, Volume and Issue: 2(3), P. 035004 - 035004

Published: Aug. 4, 2015

We introduce and validate a pressure measurement paradigm that reduces extracerebral contamination from superficial tissues in optical monitoring of cerebral blood flow with diffuse correlation spectroscopy (DCS). The scheme determines subject-specific contributions to the DCS signal by utilizing probe modulation induce variations flow. For analysis, head is modeled as two-layer medium probed long short source-detector separations. Then combination modified Beer-Lambert law for enables experimenters linearly relate differential signals variation without priori anatomical information. demonstrate algorithm's ability isolate during finger-tapping task graded scalp ischemia healthy adults. Finally, we adapt algorithm ameliorate oxygenation volume near-infrared spectroscopy.

Language: Английский

Citations

76
Highly parallel, interferometric diffusing wave spectroscopy for monitoring cerebral blood flow dynamics DOI Creative Commons
Wenjun Zhou, Oybek Kholiqov, Shau Poh Chong

et al.

Optica, Journal Year: 2018, Volume and Issue: 5(5), P. 518 - 518

Published: April 26, 2018

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

Language: Английский

Citations

67