Improved accuracy of cerebral blood flow quantification in the presence of systemic physiology cross-talk using multi-layer Monte Carlo modeling

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

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Near-Infrared Spectroscopy Assessments of Regional Cerebral Oxygen Saturation for the Prediction of Clinical Outcomes in Patients With Cardiac Arrest: A Review of Clinical Impact, Evolution, and Future Directions

Frontiers in Medicine, Journal Year: 2020, Volume and Issue: 7

Published: Oct. 29, 2020

Despite three decades of advancements in cardiopulmonary resuscitation (CPR) methods and post-resuscitation care, neurological prognosis remains poor among survivors out-of-hospital cardiac arrest, there are no reliable for predicting outcomes patients with arrest (CA). Adopting more effective monitoring may aid improving optimizing therapeutic interventions each patient. In the present review, we summarize development, evolution, potential application near-infrared spectroscopy (NIRS) adults CA, highlighting clinical relevance NIRS brain as a predictive tool both pre-hospital in-hospital settings. Several studies have reported an association between various oximetry measurements CA outcomes, suggesting that can be integrated into standardized CPR protocols, which improve CA. However, established acceptable regional cerebral oxygen saturation cut-off values differentiating patient groups based on return spontaneous circulation status outcomes. Furthermore, point at efforts considered futile to determined. Further large-scale randomized controlled trials required evaluate impact survival recovery following

Language: Английский

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Near-Infrared Spectroscopy Technique and Its Application in Biomedical Fields

IntechOpen eBooks, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 10, 2025

Near-infrared spectroscopy (NIRS) is a non-invasive monitoring technique that utilizes light transmission and absorption to continuously evaluate regional tissue oxygen saturation, delivery, metabolism. Widely adopted in modern clinical practice, NIRS particularly effective assessing cerebral oxygenation, enabling the early detection of impaired perfusion. Grounded Beer–Lambert law, relies on characteristics oxyhemoglobin deoxyhemoglobin as primary chromophores biological tissues. This chapter provides comprehensive overview technology its applications biomedical fields. It begins by discussing fundamental assumptions, advantages, limitations NIRS, along with typical structure system. Following this, principles properties are explored depth. The then delves into brain monitoring, focusing oxygenation hemodynamics. Additionally, it examines use cardiac applications, highlighting both potential challenges involved. role machine learning signal processing also demonstrated. Finally, integration other imaging modalities, including optical coherence tomography, electroencephalography, ultrasound, introduced illustrate capabilities multi-modality systems.

Language: Английский

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Diffuse correlation spectroscopy and frequency-domain near-infrared spectroscopy for measuring microvascular blood flow in dynamically exercising human muscles

Journal of Applied Physiology, Journal Year: 2019, Volume and Issue: 127(5), P. 1328 - 1337

Published: Sept. 12, 2019

In the last 20 yr, near-infrared diffuse correlation spectroscopy (DCS) has been developed for providing a noninvasive estimate of microvascular blood flow (BF) as BF index (BF i ) in human skin, muscle, breast, brain, and other tissue types. this study, we proposed new motion correction algorithm DCS-derived able to remove artifacts during cycling exercise. We tested on DCS data collected exercise demonstrated that can be used quantify muscle dynamic high-intensity addition, measured regional oxygen metabolic rate (MRO 2i by combining frequency-domain multidistance (FDNIRS) oximetry with measures. Recreationally active subjects ( n = 12; 31 ± 8 183 4 cm, 79 10 kg) pedaled at 80–100 revolutions/min until volitional fatigue work increase 30 W every min. Exercise intensity was normalized each subject power peak (W ). Both rectus femoris MRO increased from 15% up 75% then plateaued end During recovery power, remained almost constant, whereas started decrease. The /MRO plateau associated rising lactate concentration, indicating progressive involvement anaerobic metabolism. These findings further highlight utility FDNIRS effective, reproducible, techniques assess real time such cycling. NEW & NOTEWORTHY To best our knowledge, study is first demonstrate combination monitor quadriceps metabolism high temporal resolution optically parameters confirm expected relationship between flow, oxidative metabolism, production

Language: Английский

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Simultaneous measurements of tissue blood flow and oxygenation using a wearable fiber-free optical sensor

Journal of Biomedical Optics, Journal Year: 2021, Volume and Issue: 26(01)

Published: Jan. 29, 2021

Significance: There is an essential need to develop wearable multimodality technologies that can continuously measure both blood flow and oxygenation in deep tissues investigate manage various vascular/cellular diseases. Aim: To a dual-wavelength diffuse speckle contrast oximetry (DSCFO) for simultaneous measurements of variations tissues. Approach: A fiber-free DSCFO probe was fabricated using 3D printing confine two small near-infrared laser diodes tiny CMOS camera positions measurements. The spatial light intensity at the different wavelengths enable quantification tissue oxygenation, respectively. first calibrated phantoms then tested adult forearms during artery cuff occlusion. Results: Phantom tests determined largest effective source–detector distance (15 mm) optimal exposure time (10 ms) verified accuracy measuring absorption coefficient variations. detected substantial changes forearm resulting from occlusion, which meet physiological expectations are consistent with previous study results. Conclusions: may be used continuous monitoring freely behaving subjects.

Language: Английский

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近红外组织血氧检测的波长优化及实验验证

Laser & Optoelectronics Progress, Journal Year: 2024, Volume and Issue: 61(13), P. 1317001 - 1317001

Published: Jan. 1, 2024

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Systematic Review of Innovative Diagnostic Tests for Chronic Exertional Compartment Syndrome

International Journal of Sports Medicine, Journal Year: 2022, Volume and Issue: 44(01), P. 20 - 28

Published: June 1, 2022

Abstract The diagnosis chronic exertional compartment syndrome is traditionally linked to elevated intracompartmental pressures, although uncertainty regarding this diagnostic instrument increasing. aim of current review was evaluate literature for alternative tests. A search in line with PRISMA criteria conducted. Studies evaluating tests other than pressure measurements were included. Bias and quality studies evaluated using the Oxford Levels Evidence QUADAS-2 instrument. total 28 met study (MRI n=8, SPECT n=6, NIRS n=4, MRI together n=1, miscellaneous modalities n=9). Promising results reported (n=4), (n=4) (n=3). These imaging techniques rely on detecting changes signal intensity manually selected regions interest muscle compartments leg. Yet, tools protocols diverse. Moreover, five explored serving as an adjunct, rather replacing measurements. Future research warranted clinical methodological heterogeneity present high validation absent. Further optimization specific key based a patient’s history, physical examination symptom provocation may potentially render measurement redundant.

Language: Английский

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Persons with type 1 diabetes have low blood oxygen levels in the supine and standing body positions

BMJ Open Diabetes Research & Care, Journal Year: 2021, Volume and Issue: 9(1), P. e001944 - e001944

Published: May 1, 2021

Introduction Blood oxygen saturation is low compared with healthy controls (CONs) in the supine body position individuals type 1 diabetes (T1D) and has been associated complications. Since most of daily life occurs upright position, it interest if this also applies standing position. In addition, tissue oxygenation other anatomical sites could show different patterns T1D. Therefore, we investigated blood, arm forehead levels positions T1D (n=129) CONs (n=55). Research design methods was measured pulse oximetry. Arm mixed were near-infrared spectroscopy sensors applied on skin. Results Data are presented as least squares means±SEM differences (95% CIs). Overall blood lower (CON: 97.6%±0.2%; T1D: 97.0%±0.1%; difference: −0.5% CI −0.9% to −0.0%); p=0.034). all participants, increased after up (supine: 97.1%±0.1%; standing: +0.6% 0.4% 0.8%); p<0.001). However, increase smaller CON (CON supine: 97.3%±0.2%; 98.0%±0.2%; 96.9%±0.2%; 97.2%±0.1%; difference between groups change: −0.4% −0.6% −0.2%); decreased both more those Forehead there no changes when comparing groups. Conclusion Compared CON, exhibit possible detrimental adaptation standing, preserved oxygenation. Further studies needed explore consequences these differences.

Language: Английский

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Anthropomorphic Polydimethylsiloxane silicone-based phantom for Diffuse Optical Imaging

Heliyon, Journal Year: 2022, Volume and Issue: 8(8), P. e10308 - e10308

Published: Aug. 1, 2022

This work presents a method for constructing phantoms suitable diffuse optical mammography. They are based on Polydimethylsiloxane silicones, with the characteristic of being anthropomorphic, and having similar mechanical properties as real breast. These useful testing performance imaging devices in near infrared, both transmittance reflectance geometries, since they can be constructed containing inclusions, to simulate breast tumors. An alternative component used scattering agent, that is easier handle than traditional agents, also studied.The were tested varying concentration absorbing while their modified by adding silicone fluid basic mixture.Finally, Diffuse Optical Imaging experiments, these images compared ones obtained conventional ultrasound techniques.Results show anthropomorphic properly reproduce characteristics human breasts, Imaging.

Language: Английский

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Modified lambert beer for bilirubin concentration and blood oxygen saturation prediction

International Journal of Advances in Intelligent Informatics, Journal Year: 2019, Volume and Issue: 5(2), P. 113 - 113

Published: July 26, 2019

Noninvasive measurement of health parameters such as blood oxygen saturation and bilirubin concentration predicted via an appropriate light reflectance model based on the measured optical signals is eminent interest in biomedical research. This to replace use conventional invasive sampling approach. study aims investigate feasibility using Modified Lambert Beer (MLB) prediction one’s value, SO2. quantification technique a priori knowledge extinction coefficients hemoglobin derivatives wavelength range 440 – 500 nm. The validity was evaluated data from TracePro raytracing software for single-layered skin with varying concentration. results revealed some promising trends estimated mean ± standard deviation (SD) error 0.255 0.025 g/l. Meanwhile, remarkable low SD 9.11 2.48 % found SO2 value. It concluded that these errors are likely due insufficiency MLB at describing changes attenuation underlying absorption processes. In addition, this also suggested linear regression deduced work improved required parameter values.

Language: Английский

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