Journal ArticleDOI
Photon migration in the presence of a single defect: a perturbation analysis.
TLDR
An analytical perturbation analysis is presented for studying the sensitivity of diffusive photon flux to the addition of a small spherical defect object in multiple-scattering media such as human tissues.Abstract:
We present an analytical perturbation analysis for studying the sensitivity of diffusive photon flux to the addition of a small spherical defect object in multiple-scattering media such as human tissues. As a first simple application of our perturbation method, we derive analytically the photon migration path distributions and the shapes of the so-called banana regions in which the photon migration paths are concentrated. We then derive analytically the sensitivity of detected photon flux densities to the inclusion of small spherical defects in the multiple-scattering medium for both single-source and two-source configurations, at both steady-state (dc) and frequency-modulation conditions, and compare the results with Monte Carlo simulations.read more
Citations
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Optical tomography in medical imaging
TL;DR: A review of methods for the forward and inverse problems in optical tomography can be found in this paper, where the authors focus on the highly scattering case found in applications in medical imaging, and to the problem of absorption and scattering reconstruction.
Journal ArticleDOI
Optical imaging in medicine: II. Modelling and reconstruction
TL;DR: This paper considers models based on radiative transfer theory and its derivatives, which are either stochastic in nature (random walk, Monte Carlo, and Markov processes) or deterministic (partial differential equation models and their solutions).
Journal ArticleDOI
Mobile monitoring with wearable photoplethysmographic biosensors
TL;DR: The ring sensor is an ambulatory, telemetric, continuous health-monitoring device that combines miniaturized data acquisition features with advanced photoplethysmographic techniques to acquire data related to the patient's cardiovascular state using a method far superior to existing fingertip PPG sensors.
Journal ArticleDOI
Time domain functional NIRS imaging for human brain mapping
Alessandro Torricelli,Davide Contini,Antonio Pifferi,Matteo Caffini,Rebecca Re,Lucia Zucchelli,Lorenzo Spinelli +6 more
TL;DR: This review is aimed at presenting the state-of-the-art of time domain (TD) functional near-infrared spectroscopy (fNIRS) by introducing the physical principles, the basics of modeling and data analysis, and the technological developments that would pave the way for a broader use of TD fNirS in the neuroimaging community.
Journal ArticleDOI
A NIRS–fMRI investigation of prefrontal cortex activity during a working memory task
Hiroki Sato,Noriaki Yahata,Tsukasa Funane,Ryu Takizawa,Ryu Takizawa,Takusige Katura,Hirokazu Atsumori,Yukika Nishimura,Akihide Kinoshita,Masashi Kiguchi,Hideaki Koizumi,Masato Fukuda,Kiyoto Kasai +12 more
TL;DR: Supportive evidence is provided that NIRS can be used to measure hemodynamic signals originating from prefrontal cortex activation, and the results suggest that the NirS-Hb signal mainly reflects hemodynamic changes in the gray matter.
References
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Time resolved reflectance and transmittance for the non-invasive measurement of tissue optical properties.
TL;DR: A simple model is developed, based on the diffusion approximation to radiative transfer theory, which yields analytic expressions for the pulse shape in terms of the interaction coefficients of a homogeneous slab.
Journal ArticleDOI
Comparison of time-resolved and -unresolved measurements of deoxyhemoglobin in brain.
Britton Chance,John S. Leigh,H. Miyake,David S. Smith,Shoko Nioka,R Greenfeld,M Finander,K.J. Kaufmann,Warren J. Levy,M Young +9 more
TL;DR: Time-resolved spectroscopy afforded a display of the times and distances of arrival of photons emitted by the cat brain in response to a 10-ps input pulse, and deoxyhemoglobin can be quantified in brain tissues.
Journal ArticleDOI
Cotside measurement of cerebral blood flow in ill newborn infants by near infrared spectroscopy
TL;DR: A new method of quantifying cerebral blood flow which allows repeated cotside measurements is described, which ranged from 7 ml.100 g-1.min-1 after the administration of indomethacin to a very preterm infant to 33 ml.
Journal Article
Noninvasive monitoring of cerebral oxygenation in preterm infants: preliminary observations.
TL;DR: The antecedent state of cerebral oxygenation, the severity and duration of deoxygenation, and the presence or absence of circulatory abnormalities all influenced the aa3 response to hypoxia.
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Near infrared monitoring of human skeletal muscle oxygenation during forearm ischemia
TL;DR: The ability of the NIR technique to detect dynamic trends in tissue oxygenation reveals that muscle O2 is rapidly consumed during tourniquet ischemia and rapidly restored by hyperemic responses after brief ischemIA.