Near-infrared spectroscopy of the human brain: effects of apnea and hypercapnia on the intensity and phase of backscattered light

1998 ◽  
Author(s):  
Nicola Rosato ◽  
Fabrizio Vernieri ◽  
Francesco Tibuzzi ◽  
Francesco Passarelli ◽  
Alessandro F. Agro ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Human Brain ◽  
Near Infrared Spectroscopy ◽  
Near Infrared

scholarly journals Noninvasive and Wearable Optical Monitoring of Brain Death with Aid of a Protocol at Differentiated Fractions of Oxygen Inspired

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 5808-5808
Author(s):  
Ting Li ◽  
Pan Boan ◽  
Yuan Gao ◽  
Huang Xiaobo ◽  
Jiangbo Pu ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Brain Death ◽  
Human Brain ◽  
Real Time ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
High Oxygen ◽  
Phase Iii ◽  
Brain Dead ◽  
Oxygen Concentrations

Brain death is a permanent loss of all brain function [1]. Current clinical organ transplantations mostly depend on the organs from brain-dead patients [2]. And of note, a lot of blood deases are easy to cause cerebral haemorrhage, which is quite of danger and usually induce brain death if not detected and treated in time. Thus prompt evaluation of brain death is of great significance for saving medical resources and reducing economic burden of the patients' families. Current guide for diagnosing brain death required to perform a list of >30 hours neurological examninations, some of which are even invasive, not in time and easily hampered by many confounding factors. An ideal ancillary test to assess brain death is highlighted to be noninvasive, sensitive, universally available, timely, and easy to perform at the bedside. Near infrared spectroscopy ( NIRS ) is capable of monitoring hemodynamics in response to brain activity noninvasively, conveniently, continually, and relatively inexpensively, evidented by a series of clinical cerebral studies recently. Weigl et al newly reported to use a time resolved NIRS to detect the fluorescence photons excited in the indocyanine green ( ICG ) for cerebral perfusion detection. It provided a novel optical ancillary tool to assess brain death, while its accuracy was only 69.2%, which did not reach the level of brain death confirmation. Plus, it was invasive, requiring injection of optical contrast agent. We attempted to assess brain death completely in nonivasive way with just a custom wearable NIRS device developed in our lab [3] ( fig.1 a ). We novelly incororate a protocol at markedly but safely varied fractions of oxygen respiration. Firstly, Monte Carlo modeling were carried out to test the difference in photon transport within human brain at different oxygen concentrations induced by varied fractions of oxygen respiration ( FIO2 ) [4]. 18 healthy subjects ( 41 ± 11 years old ) and 17 brain dead patients were recruited from the intensive care unit (ICU) in Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital. No significant difference in age was found between patients and healthy groups ( p >0.413 ). These patients were finally clinically diagnosed by the international standards of brain death. Two protocols were used ( fig.1 b). One is consisted of 1 hour resting, 3-minute baseline measure, half-hour measurement at 60% FIO2 ( phase I, high oxygen ),a half hour measure at 40% FIO2 ( phase II, low oxygen ), and a half hour measure at 60% FIO2 ( phase III, high oxygen ). The other is low, high, and low. The Δ[Hb] and Δ[HbO2] time courses were recorded by NIRS in real time with related signal processing ( fig.1 c ). Statistical analysis were focus on the sensitivity and specificiy of our proposed methodology at combination of NIRS and above protocol, as well as which protocol act better. Fig.1 ( c right ) showed that the detected light signal profile dramatically differed among varied oxygen concentrations in human brain. Plus the hemodynamic responses varied clearly between two subject groups among varied FIO2 in both protocols ( fig1. d ). The ' II-III ' phase act more distinct in differing two groups than ' I-II ' phase. And the low-high-low protocol acted almost perfect in accessing brain death with highest sensitivity and specificity. Over all, the novel incorporation of NIRS and a low-high-low varied FIO2 protocol was shown to a be most sensitive, highly specific, noninvasive and real time way to assess brain death and promptly offer quality assured donor organs. [1] E. F. M. Wijdicks, P. N. Varelas, G. S. Gronseth, D. M. Greer, Evidence-based guideline update: Determining brain death in adults report of the quality standards subcommittee of the American Academy of Neurology, Neurology, vol. 74, no. 23, pp. 1911-1918, 2010 [2] K. Singbartl, R. Murugan, A. M. Kaynar, D. W. Crippen, S. A. Tisherman, K. Shutterly, S. A. Stuart, R. Simmons, Intensivist-led management of brain-dead donors is associated with an increase in organ recovery for transplantation, J. M. Darby, Am. J. Transplant., vol. 11, no. 7, pp. 1517-1521, 2011 [3] T. Li, M. Duan, Y. Zhao, G. Yu, Z. Ruan. Bedside monitoring of patients with shock using a portable spatially-resolved near-infrared spectroscopy. Biomed. Opt. Express, vol. 6, no. 9, pp. 3431-3436, 2015 [4] B. Pan, C. Huang, X. Fang, X. Huang, T. Li*, Noninvasive and Sensitive Optical Assessment of Brain Death, J. Biophotonics, vol. 12, no. 3, pp. e201800240, 2018 Disclosures No relevant conflicts of interest to declare.

Near-infrared spectroscopy of image clarity perception in the human brain

2014 ◽  
Author(s):  
J. E. Lugo ◽  
C. Habak ◽  
Rafael Doti ◽  
Jocelyn Faubert
Keyword(s):  
Infrared Spectroscopy ◽  
Human Brain ◽  
Near Infrared Spectroscopy ◽  
Near Infrared

scholarly journals Imaging System Based on Silicon Photomultipliers and Light Emitting Diodes for Functional Near-Infrared Spectroscopy

2020 ◽  
Vol 10 (3) ◽  
pp. 1068 ◽  
Author(s):  
Giovanni Maira ◽  
Antonio M. Chiarelli ◽  
Stefano Brafa ◽  
Sebania Libertino ◽  
Giorgio Fallica ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Human Brain ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Light Emitting Diodes ◽  
Optical Tomography ◽  
System Optimization ◽  
Infrared Light ◽  
Functional Near Infrared Spectroscopy ◽  
Light Emitting

We built a fiber-less prototype of an optical system with 156 channels each one consisting of an optode made of a silicon photomultiplier (SiPM) and a pair of light emitting diodes (LEDs) operating at 700 nm and 830 nm. The system uses functional near-infrared spectroscopy (fNIRS) and diffuse optical tomography (DOT) imaging of the cortical activity of the human brain at frequencies above 1 Hz. In this paper, we discuss testing and system optimization performed through measurements on a multi-layered optical phantom with mechanically movable parts that simulate near-infrared light scattering inhomogeneities. The baseline optical characteristics of the phantom are carefully characterized and compared to those of human tissues. Here we discuss several technical aspects of the system development, such as LED light output drift and its possible compensation, SiPM linearity, corrections of channel signal differences, and signal-to-noise ratio (SNR). We implement an imaging algorithm that investigates large phantom regions. Thanks to the use of SiPMs, very large source-to-detector distances are acquired with a high SNR and 2 Hz time resolution. The overall results demonstrate the high potentialities of a system based on SiPMs for fNIRS/DOT human brain imaging applications.

Design and Development of Two Channel Portable Near Infrared Spectroscopy System for Studies of Cerebral Oxygenation in Prefrontal Cortex of Human Brain

2014 ◽  
Vol 573 ◽  
pp. 814-818
Author(s):  
S. Bagyaraj ◽  
G. Ravindran ◽  
S. Shenbaga Devi
Keyword(s):  
Prefrontal Cortex ◽  
Infrared Spectroscopy ◽  
Human Brain ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Continuous Wave ◽  
Cerebral Oxygenation ◽  
Wave Length ◽  
Spatial Task ◽  
Functional Near Infrared Spectroscopy

Functional near infrared spectroscopy is a noninvasive, non harmful, low cost and safe optical technique that can be used to study the functional activities in the human brain. This paper describes the development of two channel Near InfraRed Spectroscopy (NIRS) system and the results of the cerebral oxygenation changes during the different cognitive tasks. The objective of the study is to design, develop a portable non-invasive continuous wave NIRS system with dual wave length for determining the hemoglobin content of the blood chromophores during different activities of the prefrontal cortex of the brain. The two channel NIRS system designed and it was tested with 20 healthy, ie.,15 males and 5 females with an average age group of 21±2.25, they were given a 2 different mental tasks such as sequential subtraction (mathematical task) and spot the difference (Visuo-spatial task) and their Oxy & de-Oxy hemoglobin concentration was measured which showed more changes during the task period when compared to relaxation in both left and right part of pre-frontal cortex.

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