Time-resolved near infrared light propagation using frequency domain superposition

Wojtkiewicz, Stanisław; Durdurán, Turgut; Dehghani, Hamid

doi:10.1364/boe.9.000041

Cited by 10 publications

(9 citation statements)

References 46 publications

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“…However, if only frequencies lower than 1.5 GHz are used the reconstructions suffers from instabilities. This agrees with the results of [45] that suggest that useful information can be found at GHz order.…”

Section: Comparing Windows and Frequency-based Reconstructionsupporting

confidence: 92%

Improving Localization of Deep Inclusions in Time-Resolved Diffuse Optical Tomography

et al. 2019

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Time-resolved diffuse optical tomography is a technique used to recover the optical properties of an unknown diffusive medium by solving an ill-posed inverse problem. In time-domain, reconstructions based on datatypes are used for their computational efficiency. In practice, most used datatypes are temporal windows and Fourier transform. Nevertheless, neither theoretical nor numerical studies assessing different datatypes have been clearly expressed. In this paper, we propose an overview and a new process to compute efficiently a long set of temporal windows in order to perform diffuse optical tomography. We did a theoretical comparison of these large set of temporal windows. We also did simulations in a reflectance geometry with a spherical inclusion at different depths. The results are presented in terms of inclusion localization and its absorption coefficient recovery. We show that (1) the new windows computed with the developed method improve inclusion localization for inclusions at deep layers, (2) inclusion absorption quantification is improved at all depths and, (3) in some cases these windows can be equivalent to frequency based reconstruction at GHz order.

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Section: Comparing Windows and Frequency-based Reconstructionsupporting

confidence: 92%

Improving Localization of Deep Inclusions in Time-Resolved Diffuse Optical Tomography

et al. 2019

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“…So the tissue properties affecting spectral light propagation including absorption coefficient and reduced scattering coefficient are the properties averaged over a bulk volume of tissue to manage analytical treatment. Analysis of the problem in tissue that is optically inhomogeneous can be done by using numerical techniques such as time-domain finite element approach [52]. Further, cellwise or molecular-size analysis of the light propagation delay caused by scattering may not be prohibitive, but the analytical and computational costs will be humongous and the outcomes will have to be assembled over a bulk organism as big as human size for health potential, whereby the volume averaging will make the use of bulk-tissue optical properties valid unless the sites of photogenesis need to be spatially resolved and that does not seem to be possible without more analytical and mechanistical discoveries to resolve the pathways that could be both complex and numerous.…”

Section: Temporal Propagation Of Light Of Spectral Relevancy To Inducmentioning

confidence: 99%

On the stress-induced photon emission from organism: I, will the scattering-limited delay affect the temporal course?

Piao

2020

SN Appl. Sci.

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Much remains to be identified for the temporal course of stress-induced photon emission (PE) from organism following stress of various types including but not limited to light. Induced PE concerns surface light emission in excess of the baseline level of spontaneous ultraweak photon emission, in response to a localized or systematic stress via oxidative bursting. It is proposed that the surface emission of induced PE involves two causally sequential phases: a stress-transfer phase that transforms the stress to perturb photogenesis balanced at homeostasis and a photon-propagation phase that transmits the photons from the domain of perturbed photogenesis to surface emission. The traversing of induced PE photons from wherever the domains of photogenesis perturbation are in the organism following the stress to the surface must involve photon propagation of which the scattering will affect the photon lifetime. Induced PE is usually substantially retarded in occurrence or longer in duration with respect to the stress. In order to identify whether the time course of induced PE can be attributed entirely to the stress-perturbed photogenesis, Part I estimates the upper limit of the scattering-caused photon lifetime following photogenesis. The estimation of that upper limit is based on setting the photogenesis at the center of a spherical human-size tissue having an unrealistically strong tissue scattering. Time-resolved photon migration analysis reveals that the scattering-limited lifetime will not be greater than 100 ns at a human scale. The time course of induced PE reported thus suggests a much retarded and slower perturbation to photogenesis with respect to the time course of stress for manifesting the surface-observed induced PE. The theoretical insight, which may complement the soliton mechanism, also supports the exploration of entopic phenomena including phosphenes and negative afterimages via delayed PE. The subsequent Part II hypothesizes a few stress-transfer kinetic patterns feeding the photogenesis.

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“…The use of the FD-NIRS facilitates measurement of the phase-shift according to the SD distance as well as the intensity levels. 83–87 Therefore, the ICG passage through the layers measured with a FD-NIRS can also be divided using the model described in section ‘Single-channel frequency-domain’ adapted to a multidistance approach system. 41…”

Section: Limitationsmentioning

confidence: 99%

Cerebral perfusion and blood–brain barrier assessment in brain trauma using contrast-enhanced near-infrared spectroscopy with indocyanine green: A review

Forcione

Chiarelli

Davies

et al. 2020

J Cereb Blood Flow Metab

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Contrast-enhanced near-infrared spectroscopy (NIRS) with indocyanine green (ICG) can be a valid non-invasive, continuous, bedside neuromonitoring tool. However, its usage in moderate and severe traumatic brain injury (TBI) patients can be unprecise due to their clinical status. This review is targeted at researchers and clinicians involved in the development and application of contrast-enhanced NIRS for the care of TBI patients and can be used to design future studies. This review describes the methods developed to monitor the brain perfusion and the blood–brain barrier integrity using the changes of diffuse reflectance during the ICG passage and the results on studies in animals and humans. The limitations in accuracy of these methods when applied on TBI patients and the proposed solutions to overcome them are discussed. Finally, the analysis of relative parameters is proposed as a valid alternative over absolute values to address some current clinical needs in brain trauma care. In conclusion, care should be taken in the translation of the optical signal into absolute physiological parameters of TBI patients, as their clinical status must be taken into consideration. Discussion on where and how future studies should be directed to effectively incorporate contrast-enhanced NIRS into brain trauma care is given.

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Time-resolved near infrared light propagation using frequency domain superposition

Cited by 10 publications

References 46 publications

Improving Localization of Deep Inclusions in Time-Resolved Diffuse Optical Tomography

Improving Localization of Deep Inclusions in Time-Resolved Diffuse Optical Tomography

On the stress-induced photon emission from organism: I, will the scattering-limited delay affect the temporal course?

Cerebral perfusion and blood–brain barrier assessment in brain trauma using contrast-enhanced near-infrared spectroscopy with indocyanine green: A review

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