Journal ArticleDOI
Near-infrared light propagation in an adult head model. II. Effect of superficial tissue thickness on the sensitivity of the near-infrared spectroscopy signal
Eiji Okada,David T. Delpy +1 more
Reads0
Chats0
TLDR
Light propagation in adult head models is predicted by Monte Carlo simulation to investigate the effect of the superficial tissue thickness on the partial optical path length in the brain and on the spatial sensitivity profile and results indicate that it is not appropriate to use the mean optical length as an alternative to the partial Optical path length to compensate the NIRS signal for the difference in sensitivity caused by variation of the shallow tissue thickness.Abstract:
It is important for near-infrared spectroscopy (NIRS) and imaging to estimate the sensitivity of the detected signal to the change in hemoglobin that results from brain activation and the volume of tissue interrogated for a specific source-detector fiber spacing. In this study light propagation in adult head models is predicted by Monte Carlo simulation to investigate the effect of the superficial tissue thickness on the partial optical path length in the brain and on the spatial sensitivity profile. In the case of source-detector spacing of 30 mm, the partial optical path length depends mainly on the depth of the inner skull surface whereas the spatial sensitivity profile is significantly affected by the thickness of the cerebrospinal fluid layer. The mean optical path length that can be measured by time-resolved experiments increases when the skull thickness increases whereas the partial mean optical path length in the brain decreases when the skull thickness increases. These results indicate that it is not appropriate to use the mean optical path length as an alternative to the partial optical path length to compensate the NIRS signal for the difference in sensitivity caused by variation of the superficial tissue thickness.read more
Citations
More filters
Journal Article
From Jobsis to the present day: a review of clinical near-infrared spectroscopy measurements of cerebral cytochrome-c-oxidase (vol 21, 091307, 2016)
TL;DR: Near-infrared spectroscopy measurements of cytochrome-c-oxidase have the potential to yield crucial information about cerebral metabolism at the patient bedside and this signal continues to hold significant interest in the understanding of the human brain in health and disease.
Journal ArticleDOI
Investigation of cerebral haemodynamics by near-infrared spectroscopy in young healthy volunteers reveals posture-dependent spontaneous oscillations
TL;DR: Systemic and cerebral changes appeared to preserve adequate blood flow and cerebral perfusion during standing in healthy volunteers, and oscillatory changes in [O2Hb] and TOI, which may be related to the degree of cerebral sympathetic stimulation, are posture dependent in healthy subjects.
Journal ArticleDOI
Optical imaging of infants' neurocognitive development: recent advances and perspectives.
TL;DR: Although NIRS studies of the infant brain have yet to fulfill their potential, a review of the work done so far indicates that NirS is likely to provide many unique insights in the field of developmental neuroscience.
Journal ArticleDOI
The NIRS Analysis Package: Noise Reduction and Statistical Inference
TL;DR: This work presents a comprehensive framework for noise reduction and statistical inference, which is custom-tailored to the noise characteristics of NIRS, and validate NAP using both simulated and actual data, showing marked improvement in the detection power and reliability of NirS.
Journal ArticleDOI
Intersubject variability of near-infrared spectroscopy signals during sensorimotor cortex activation
Hiroki Sato,Yutaka Fuchino,Masashi Kiguchi,Takusige Katura,Atsushi Maki,Takeshi Yoro,Hideaki Koizumi +6 more
TL;DR: The results suggest that NIR topography is useful for observing brain activity in most cases, although intersubject signal variability still needs to be resolved.
References
More filters
Journal ArticleDOI
Estimation of optical pathlength through tissue from direct time of flight measurement
TL;DR: Monte Carlo modelling of light pulses in tissue has shown that the mean value of the time dispersed light pulse correlates with the pathlength used in quantitative spectroscopic calculations, and this result has been verified in a phantom material.
Journal ArticleDOI
Spatial and temporal analysis of human motor activity using noninvasive NIR topography
Atsushi Maki,Yuichi Yamashita,Yoshitoshi Ito,Eiju Watanabe,Yoshiaki Mayanagi,Hideaki Koizumi +5 more
TL;DR: It was found that the regional change in cerebral blood volume in the primary motor area overlaps the global change around the motor cortex.
Journal ArticleDOI
Near-infrared optical properties of ex vivo human skin and subcutaneous tissues measured using the Monte Carlo inversion technique
TL;DR: The absorption and transport scattering coefficients of c Caucasian and negroid dermis, subdermal fat and muscle have been measured for all wavelengths between 620 and 1000 nm and the optical properties of caucasian dermis were found to be approximately twice those of the underlying fat layer.
Journal ArticleDOI
A Monte Carlo model for the absorption and flux distributions of light in tissue
Brian C. Wilson,Gerhard Adam +1 more
TL;DR: A Monte Carlo computer model has been used to predict the distribution of absorbed dose in homogeneous tissues of different absorption/scattering ratios, for illumination both by external light beams and via implanted optical fibers.
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).