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Markow ZE, Trobaugh JW, Richter EJ, Tripathy K, Rafferty SM, Svoboda AM, Schroeder ML, Burns-Yocum TM, Bergonzi KM, Chevillet MA, Mugler EM, Eggebrecht AT, Culver JP. Ultra-high density imaging arrays for diffuse optical tomography of human brain improve resolution, signal-to-noise, and information decoding. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.21.549920. [PMID: 37547013 PMCID: PMC10401969 DOI: 10.1101/2023.07.21.549920] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
Functional magnetic resonance imaging (fMRI) has dramatically advanced non-invasive human brain mapping and decoding. Functional near-infrared spectroscopy (fNIRS) and high-density diffuse optical tomography (HD-DOT) non-invasively measure blood oxygen fluctuations related to brain activity, like fMRI, at the brain surface, using more-lightweight equipment that circumvents ergonomic and logistical limitations of fMRI. HD-DOT grids have smaller inter-optode spacing (∼13 mm) than sparse fNIRS (∼30 mm) and therefore provide higher image quality, with spatial resolution ∼1/2 that of fMRI. Herein, simulations indicated reducing inter-optode spacing to 6.5 mm would further improve image quality and noise-resolution tradeoff, with diminishing returns below 6.5 mm. We then constructed an ultra-high-density DOT system (6.5-mm spacing) with 140 dB dynamic range that imaged stimulus-evoked activations with 30-50% higher spatial resolution and repeatable multi-focal activity with excellent agreement with participant-matched fMRI. Further, this system decoded visual stimulus position with 19-35% lower error than previous HD-DOT, throughout occipital cortex.
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2
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Shatzer HE, Russo FA. Brightening the Study of Listening Effort with Functional Near-Infrared Spectroscopy: A Scoping Review. Semin Hear 2023; 44:188-210. [PMID: 37122884 PMCID: PMC10147513 DOI: 10.1055/s-0043-1766105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/09/2023] Open
Abstract
Listening effort is a long-standing area of interest in auditory cognitive neuroscience. Prior research has used multiple techniques to shed light on the neurophysiological mechanisms underlying listening during challenging conditions. Functional near-infrared spectroscopy (fNIRS) is growing in popularity as a tool for cognitive neuroscience research, and its recent advances offer many potential advantages over other neuroimaging modalities for research related to listening effort. This review introduces the basic science of fNIRS and its uses for auditory cognitive neuroscience. We also discuss its application in recently published studies on listening effort and consider future opportunities for studying effortful listening with fNIRS. After reading this article, the learner will know how fNIRS works and summarize its uses for listening effort research. The learner will also be able to apply this knowledge toward generation of future research in this area.
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Affiliation(s)
- Hannah E. Shatzer
- Department of Psychology, Toronto Metropolitan University, Toronto, Canada
| | - Frank A. Russo
- Department of Psychology, Toronto Metropolitan University, Toronto, Canada
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3
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Jiang S, Carpenter LL, Jiang H. Optical neuroimaging: advancing transcranial magnetic stimulation treatments of psychiatric disorders. Vis Comput Ind Biomed Art 2022; 5:22. [PMID: 36071259 PMCID: PMC9452613 DOI: 10.1186/s42492-022-00119-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Accepted: 08/22/2022] [Indexed: 11/10/2022] Open
Abstract
Transcranial magnetic stimulation (TMS) has been established as an important and effective treatment for various psychiatric disorders. However, its effectiveness has likely been limited due to the dearth of neuronavigational tools for targeting purposes, unclear ideal stimulation parameters, and a lack of knowledge regarding the physiological response of the brain to TMS in each psychiatric condition. Modern optical imaging modalities, such as functional near-infrared spectroscopy and diffuse optical tomography, are promising tools for the study of TMS optimization and functional targeting in psychiatric disorders. They possess a unique combination of high spatial and temporal resolutions, portability, real-time capability, and relatively low costs. In this mini-review, we discuss the advent of optical imaging techniques and their innovative use in several psychiatric conditions including depression, panic disorder, phobias, and eating disorders. With further investment and research in the development of these optical imaging approaches, their potential will be paramount for the advancement of TMS treatment protocols in psychiatry.
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Fan W, Dehghani H, Eggebrecht AT. Investigation of effect of modulation frequency on high-density diffuse optical tomography image quality. NEUROPHOTONICS 2021; 8:045002. [PMID: 34849379 PMCID: PMC8612746 DOI: 10.1117/1.nph.8.4.045002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 11/04/2021] [Indexed: 05/16/2023]
Abstract
Significance: By incorporating multiple overlapping functional near-infrared spectroscopy (fNIRS) measurements, high-density diffuse optical tomography (HD-DOT) images human brain function with fidelity comparable to functional magnetic resonance imaging (fMRI). Previous work has shown that frequency domain high-density diffuse optical tomography (FD-HD-DOT) may further improve image quality over more traditional continuous wave (CW) HD-DOT. Aim: The effects of modulation frequency on image quality as obtainable with FD-HD-DOT is investigated through simulations with a realistic noise model of functional activations in human head models, arising from 11 source modulation frequencies between CW and 1000 MHz. Approach: Simulations were performed using five representative head models with an HD regular grid of 158 light sources and 166 detectors and an empirically derived noise model. Functional reconstructions were quantitatively assessed with multiple image quality metrics including the localization error (LE), success rate, full width at half maximum, and full volume at half maximum (FVHM). All metrics were evaluated against CW-based models. Results: Compared to CW, localization accuracy is improved by >40% throughout brain depths of 13 to 25 mm below the surface with 300 to 500 MHz modulation frequencies. Additionally, the reliable field of view in brain tissue is enlarged by 35% to 48% within an optimal frequency of 300 MHz after considering realistic noise, depending on the dynamic range of the system. Conclusions: These results point to the tremendous opportunities in further development of high bandwidth FD-HD-DOT system hardware for applications in human brain mapping.
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Affiliation(s)
- Weihao Fan
- Washington University, Department of Physics, St. Louis, Missouri, United States
| | - Hamid Dehghani
- University of Birmingham, School of Computer Science, Birmingham, United Kingdom
| | - Adam T. Eggebrecht
- Washington University School of Medicine, Mallinckrodt Institute of Radiology, St. Louis, Missouri, United States
- Washington University, Department of Biomedical Engineering, St. Louis, Missouri, United States
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5
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Jiang S, Huang J, Yang H, Wagoner R, Kozel FA, Currier G, Jiang H. Neuroimaging of depression with diffuse optical tomography during repetitive transcranial magnetic stimulation. Sci Rep 2021; 11:7328. [PMID: 33795763 PMCID: PMC8016845 DOI: 10.1038/s41598-021-86751-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 03/10/2021] [Indexed: 12/02/2022] Open
Abstract
Repetitive transcranial magnetic stimulation (rTMS) is an effective and safe treatment for depression; however, its potential has likely been hindered due to non-optimized targeting, unclear ideal stimulation parameters, and lack of information regarding how the brain is physiologically responding during and after stimulation. While neuroimaging is ideal for obtaining such critical information, existing modalities have been limited due to poor resolutions, along with significant noise interference from the electromagnetic spectrum. In this study, we used a novel diffuse optical tomography (DOT) device in order to advance our understanding of the neurophysiological effects of rTMS in depression. Healthy and depressed subjects aged 18–70 were recruited. Treatment parameters were standardized with targeting of the left dorsolateral prefrontal cortex with a magnetic field intensity of 100% of motor threshold, pulse frequency of 10 per second, a 4 s stimulation time and a 26 s rest time. DOT imaging was simultaneously acquired from the contralateral dorsolateral prefrontal cortex. Six healthy and seven depressed subjects were included for final analysis. Hemoglobin changes and volumetric three-dimensional activation patterns were successfully captured. Depressed subjects were observed to have a delayed and less robust response to rTMS with a decreased volume of activation compared to healthy subjects. In this first-in-human study, we demonstrated the ability of DOT to safely and reliably capture and compare cortical response patterns to rTMS in depressed and healthy subjects. We introduced this emerging optical functional imaging modality as a novel approach to investigating targeting, new treatment parameters, and physiological effects of rTMS in depression.
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Affiliation(s)
- Shixie Jiang
- Department of Psychiatry and Behavioral Neurosciences, University of South Florida, Tampa, FL, USA
| | - Jingyu Huang
- Department of Medical Engineering, University of South Florida, 4202 E. Fowler Avenue, ENG 030, Tampa, FL, USA
| | - Hao Yang
- Department of Medical Engineering, University of South Florida, 4202 E. Fowler Avenue, ENG 030, Tampa, FL, USA
| | - Ryan Wagoner
- Department of Psychiatry and Behavioral Neurosciences, University of South Florida, Tampa, FL, USA
| | - F Andrew Kozel
- Department of Psychiatry and Behavioral Neurosciences, University of South Florida, Tampa, FL, USA.,Department of Behavioral Sciences and Social Medicine, Florida State University, Tallahassee, FL, USA
| | - Glenn Currier
- Department of Psychiatry and Behavioral Neurosciences, University of South Florida, Tampa, FL, USA
| | - Huabei Jiang
- Department of Medical Engineering, University of South Florida, 4202 E. Fowler Avenue, ENG 030, Tampa, FL, USA.
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Vidal-Rosas EE, Zhao H, Nixon-Hill RW, Smith G, Dunne L, Powell S, Cooper RJ, Everdell NL. Evaluating a new generation of wearable high-density diffuse optical tomography technology via retinotopic mapping of the adult visual cortex. NEUROPHOTONICS 2021; 8:025002. [PMID: 33842667 PMCID: PMC8033536 DOI: 10.1117/1.nph.8.2.025002] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 03/17/2021] [Indexed: 05/06/2023]
Abstract
Significance: High-density diffuse optical tomography (HD-DOT) has been shown to approach the resolution and localization accuracy of blood oxygen level dependent-functional magnetic resonance imaging in the adult brain by exploiting densely spaced, overlapping samples of the probed tissue volume, but the technique has to date required large and cumbersome optical fiber arrays. Aim: To evaluate a wearable HD-DOT system that provides a comparable sampling density to large, fiber-based HD-DOT systems, but with vastly improved ergonomics. Approach: We investigated the performance of this system by replicating a series of classic visual stimulation paradigms, carried out in one highly sampled participant during 15 sessions to assess imaging performance and repeatability. Results: Hemodynamic response functions and cortical activation maps replicate the results obtained with larger fiber-based systems. Our results demonstrate focal activations in both oxyhemoglobin and deoxyhemoglobin with a high degree of repeatability observed across all sessions. A comparison with a simulated low-density array explicitly demonstrates the improvements in spatial localization, resolution, repeatability, and image contrast that can be obtained with this high-density technology. Conclusions: The system offers the possibility for minimally constrained, spatially resolved functional imaging of the human brain in almost any environment and holds particular promise in enabling neuroscience applications outside of the laboratory setting. It also opens up new opportunities to investigate populations unsuited to traditional imaging technologies.
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Affiliation(s)
- Ernesto E. Vidal-Rosas
- University College London, Diffuse Optical Tomography of the Human Brain Research Group, Biomedical Optics Research Laboratory, Department of Medical Physics and Biomedical Engineering, London, United Kingdom
- Address all correspondence to Ernesto E. Vidal-Rosas,
| | - Hubin Zhao
- University College London, Diffuse Optical Tomography of the Human Brain Research Group, Biomedical Optics Research Laboratory, Department of Medical Physics and Biomedical Engineering, London, United Kingdom
- University of Glasgow, James Watt School of Engineering, Glasgow, United Kingdom
| | - Reuben W. Nixon-Hill
- Imperial College London, Department of Mathematics, London, United Kingdom
- Gowerlabs Ltd., London, United Kingdom
| | | | | | - Samuel Powell
- Gowerlabs Ltd., London, United Kingdom
- Nottingham University, Department of Electrical and Electronic Engineering, Nottingham, United Kingdom
| | - Robert J. Cooper
- University College London, Diffuse Optical Tomography of the Human Brain Research Group, Biomedical Optics Research Laboratory, Department of Medical Physics and Biomedical Engineering, London, United Kingdom
| | - Nicholas L. Everdell
- University College London, Diffuse Optical Tomography of the Human Brain Research Group, Biomedical Optics Research Laboratory, Department of Medical Physics and Biomedical Engineering, London, United Kingdom
- Gowerlabs Ltd., London, United Kingdom
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7
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Deconvolution of hemodynamic responses along the cortical surface using personalized functional near infrared spectroscopy. Sci Rep 2021; 11:5964. [PMID: 33727581 PMCID: PMC7966407 DOI: 10.1038/s41598-021-85386-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 02/26/2021] [Indexed: 11/28/2022] Open
Abstract
In functional near infrared spectroscopy (fNIRS), deconvolution analysis of oxy and deoxy-hemoglobin concentration changes allows estimating specific hemodynamic response functions (HRF) elicited by neuronal activity, taking advantage of the fNIRS excellent temporal resolution. Diffuse optical tomography (DOT) is also becoming the new standard reconstruction procedure as it is more accurate than the modified Beer Lambert law approach at the sensor level. The objective of this study was to assess the relevance of HRF deconvolution after DOT constrained along the cortical surface. We used local personalized fNIRS montages which consists in optimizing the position of fNIRS optodes to ensure maximal sensitivity to subject specific target brain regions. We carefully evaluated the accuracy of deconvolution when applied after DOT, using realistic simulations involving several HRF models at different signal to noise ratio (SNR) levels and on real data related to motor and visual tasks in healthy subjects and from spontaneous pathological activity in one patient with epilepsy. We demonstrated that DOT followed by deconvolution was able to accurately recover a large variability of HRFs over a large range of SNRs. We found good performances of deconvolution analysis for SNR levels usually encountered in our applications and we were able to reconstruct accurately the temporal dynamics of HRFs in real conditions.
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8
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Hernandez-Martin E, Gonzalez-Mora JL. Diffuse optical tomography in the human brain: A briefly review from the neurophysiology to its applications. BRAIN SCIENCE ADVANCES 2021. [DOI: 10.26599/bsa.2020.9050014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The present work describes the use of noninvasive diffuse optical tomography (DOT) technology to measure hemodynamic changes, providing relevant information which helps to understand the basis of neurophysiology in the human brain. Advantages such as portability, direct measurements of hemoglobin state, temporal resolution, non‐restricted movements as occurs in magnetic resonance imaging (MRI) devices mean that DOT technology can be used in research and clinical fields. In this review we covered the neurophysiology, physical principles underlying optical imaging during tissue‐light interactions, and technology commonly used during the construction of a DOT device including the source‐detector requirements to improve the image quality. DOT provides 3D cerebral activation images due to complex mathematical models which describe the light propagation inside the tissue head. Moreover, we describe briefly the use of Bayesian methods for raw DOT data filtering as an alternative to linear filters widely used in signal processing, avoiding common problems such as the filter selection or a false interpretation of the results which is sometimes due to the interference of background physiological noise with neural activity.
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Affiliation(s)
- Estefania Hernandez-Martin
- Department of Basic Medical Science, Faculty of Health Science, Medicine Section, Universidad de La Laguna, 38071, Spain
| | - José Luis Gonzalez-Mora
- Department of Basic Medical Science, Faculty of Health Science, Medicine Section, Universidad de La Laguna, 38071, Spain
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9
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Fishell AK, Arbeláez AM, Valdés CP, Burns-Yocum TM, Sherafati A, Richter EJ, Torres M, Eggebrecht AT, Smyser CD, Culver JP. Portable, field-based neuroimaging using high-density diffuse optical tomography. Neuroimage 2020; 215:116541. [PMID: 31987995 DOI: 10.1016/j.neuroimage.2020.116541] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 12/10/2019] [Accepted: 01/10/2020] [Indexed: 12/17/2022] Open
Abstract
Behavioral and cognitive tests in individuals who were malnourished as children have revealed malnutrition-related deficits that persist throughout the lifespan. These findings have motivated recent neuroimaging investigations that use highly portable functional near-infrared spectroscopy (fNIRS) instruments to meet the demands of brain imaging experiments in low-resource environments and enable longitudinal investigations of brain function in the context of long-term malnutrition. However, recent studies in healthy subjects have demonstrated that high-density diffuse optical tomography (HD-DOT) can significantly improve image quality over that obtained with sparse fNIRS imaging arrays. In studies of both task activations and resting state functional connectivity, HD-DOT is beginning to approach the data quality of fMRI for superficial cortical regions. In this work, we developed a customized HD-DOT system for use in malnutrition studies in Cali, Colombia. Our results evaluate the performance of the HD-DOT instrument for assessing brain function in a cohort of malnourished children. In addition to demonstrating portability and wearability, we show the HD-DOT instrument's sensitivity to distributed brain responses using a sensory processing task and measurements of homotopic functional connectivity. Task-evoked responses to the passive word listening task produce activations localized to bilateral superior temporal gyrus, replicating previously published work using this paradigm. Evaluating this localization performance across sparse and dense reconstruction schemes indicates that greater localization consistency is associated with a dense array of overlapping optical measurements. These results provide a foundation for additional avenues of investigation, including identifying and characterizing a child's individual malnutrition burden and eventually contributing to intervention development.
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Affiliation(s)
- Andrew K Fishell
- Washington University School of Medicine, Division of Biology and Biomedical Sciences, St. Louis, MO, USA; Washington University School of Medicine, Mallinckrodt Institute of Radiology, St. Louis, MO, USA
| | - Ana María Arbeláez
- Washington University School of Medicine, Department of Pediatrics, St. Louis, MO, USA
| | | | - Tracy M Burns-Yocum
- Indiana University, Department of Psychological and Brain Sciences, Bloomington, IN, USA
| | - Arefeh Sherafati
- Washington University School of Medicine, Division of Biology and Biomedical Sciences, St. Louis, MO, USA; Washington University, Department of Physics, St. Louis, MO, USA
| | - Edward J Richter
- Washington University, Electrical and Systems Engineering, St. Louis, MO, USA
| | | | - Adam T Eggebrecht
- Washington University School of Medicine, Mallinckrodt Institute of Radiology, St. Louis, MO, USA; Washington University School of Medicine, Department of Pediatrics, St. Louis, MO, USA
| | - Christopher D Smyser
- Washington University School of Medicine, Mallinckrodt Institute of Radiology, St. Louis, MO, USA; Washington University School of Medicine, Department of Pediatrics, St. Louis, MO, USA; Washington University School of Medicine, Department of Neurology, St. Louis, MO, USA
| | - Joseph P Culver
- Washington University School of Medicine, Division of Biology and Biomedical Sciences, St. Louis, MO, USA; Washington University School of Medicine, Mallinckrodt Institute of Radiology, St. Louis, MO, USA; Washington University, Department of Physics, St. Louis, MO, USA; Washington University, Department of Biomedical Engineering, MO, St. Louis, USA.
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10
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Bejm K, Wojtkiewicz S, Sawosz P, Perdziak M, Pastuszak Z, Sudakou A, Guchek P, Liebert A. Influence of contrast-reversing frequency on the amplitude and spatial distribution of visual cortex hemodynamic responses. BIOMEDICAL OPTICS EXPRESS 2019; 10:6296-6312. [PMID: 31853401 PMCID: PMC6913388 DOI: 10.1364/boe.10.006296] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 10/26/2019] [Accepted: 10/26/2019] [Indexed: 06/10/2023]
Abstract
Visual stimulation is one of the most commonly used paradigms for cerebral cortex function investigation. Experiments typically involve presenting to a volunteer a black-and-white checkerboard with contrast-reversing at a frequency of 4 to 16 Hz. The aim of the present study was to investigate the influence of the flickering frequency on the amplitude of changes in the concentration of oxygenated and deoxygenated hemoglobin. The hemoglobin concentrations were assessed with the use of a high resolution diffuse optical tomography method. Spatial distributions of changes in hemoglobin concentrations overlaying the visual cortex are shown for various stimuli frequencies. Moreover, the hemoglobin concentration changes obtained for different source-detector separations (from 1.5 to 5.4 cm) are presented. Our results demonstrate that the flickering frequency had a statistically significant effect on the induced oxyhemoglobin changes (p < 0,001). The amplitude of oxy hemoglobin concentration changes at a frequency of 8 Hz was higher in comparison with that measured at 4 Hz :[median(25th-75thpercentiles) 1.24 (0.94-1.71) vs. 0.92(0.73-1.28)µM, p < 0.001]; 12 Hz:[1.24 (0.94-1.71) vs. 1.04 (0.78-1.32) µM, p < 0.001]; and 16 Hz:[1.24 (0.94-1.71) vs. 1.15(0.87-1.48) µM, p < 0.001]. No significant differences were observed between the size of an area of activation for various frequencies. The demonstrated superiority of 8 Hz over other frequencies can advance understanding of visual stimulations and help guide future fNIRS protocols.
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Affiliation(s)
- Karolina Bejm
- Nalecz Institute of Biocybernetics and
Biomedical Engineering Polish Academy of Sciences, Warsaw, Poland
| | - Stanisław Wojtkiewicz
- Nalecz Institute of Biocybernetics and
Biomedical Engineering Polish Academy of Sciences, Warsaw, Poland
| | - Piotr Sawosz
- Nalecz Institute of Biocybernetics and
Biomedical Engineering Polish Academy of Sciences, Warsaw, Poland
| | - Maciej Perdziak
- Department of Ophthalmology and Optometry
Poznan University of Medical Sciences, Poznan, Poland
- Laboratory of Vision Science and Optometry,
Faculty of Physics, Adam Mickiewicz University, Poznan, Poland
| | - Zanna Pastuszak
- Department of Neurosurgery, Mossakowski
Medical Research Center Polish Academy of Sciences, Warsaw, Poland
| | - Aleh Sudakou
- Nalecz Institute of Biocybernetics and
Biomedical Engineering Polish Academy of Sciences, Warsaw, Poland
| | - Petro Guchek
- Nalecz Institute of Biocybernetics and
Biomedical Engineering Polish Academy of Sciences, Warsaw, Poland
| | - Adam Liebert
- Nalecz Institute of Biocybernetics and
Biomedical Engineering Polish Academy of Sciences, Warsaw, Poland
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11
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Schumacher FK, Steinborn C, Weiller C, Schelter BO, Reinhard M, Kaller CP. The impact of physiological noise on hemodynamic-derived estimates of directed functional connectivity. Brain Struct Funct 2019; 224:3145-3157. [DOI: 10.1007/s00429-019-01954-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 08/31/2019] [Indexed: 11/29/2022]
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12
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Zhang F, Cheong D, Chen Y, Khan A, Ding L, Yuan H. Superficial Fluctuations in Functional Near-Infrared Spectroscopy. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2019; 2019:4779-4782. [PMID: 31946930 DOI: 10.1109/embc.2019.8856349] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Functional near-infrared spectroscopy (fNIRS) is a non-invasive optical functional neuroimaging that has seen rapid development and increasing use in studying human brain under normal and diseased conditions. Compared with blood-oxygenation-level dependent functional magnetic resonance imaging (BOLD fMRI), fNIRS offers advantages including its low cost, portability and compatibility with implanted medical devices. Thus, fNIRS can be used to monitor brain activity particularly in infants, elders and patients who are unable to undergo routine fMRI scans. However, fNIRS suffers from its susceptibility to scalp and to systemic physiological noises. Fluctuations originated from heartbeat, respiration and low-frequency oscillations lead to contamination of cerebral activity. In order to tap the full potential of fNIRS, it is essential to eliminate these confounding noises from fNIRS measurements. Therefore, the present study aims to understand the underlying relationship between superficial signals and the compound signals respectively measured by short channels and long channels of fNIRS optodes in a whole head configuration. Our results reveal that: 1) 49.56% of total variances in long-channel data are contributed by a global component shared across all long channels; 2) this global component is significantly correlated with the superficial fluctuations extracted from short-channel data. Finally, our findings indicate that compound signals measured by long channels of fNIRS are contaminated by superficial fluctuations and that careful removal of these fluctuations from long-channel data is critical in obtaining accurate images of cerebral activity with fNIRS.
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13
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Wheelock MD, Culver JP, Eggebrecht AT. High-density diffuse optical tomography for imaging human brain function. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2019; 90:051101. [PMID: 31153254 PMCID: PMC6533110 DOI: 10.1063/1.5086809] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2018] [Accepted: 04/14/2019] [Indexed: 05/08/2023]
Abstract
This review describes the unique opportunities and challenges for noninvasive optical mapping of human brain function. Diffuse optical methods offer safe, portable, and radiation free alternatives to traditional technologies like positron emission tomography or functional magnetic resonance imaging (fMRI). Recent developments in high-density diffuse optical tomography (HD-DOT) have demonstrated capabilities for mapping human cortical brain function over an extended field of view with image quality approaching that of fMRI. In this review, we cover fundamental principles of the diffusion of near infrared light in biological tissue. We discuss the challenges involved in the HD-DOT system design and implementation that must be overcome to acquire the signal-to-noise necessary to measure and locate brain function at the depth of the cortex. We discuss strategies for validation of the sensitivity, specificity, and reliability of HD-DOT acquired maps of cortical brain function. We then provide a brief overview of some clinical applications of HD-DOT. Though diffuse optical measurements of neurophysiology have existed for several decades, tremendous opportunity remains to advance optical imaging of brain function to address a crucial niche in basic and clinical neuroscience: that of bedside and minimally constrained high fidelity imaging of brain function.
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Affiliation(s)
- Muriah D. Wheelock
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
| | | | - Adam T. Eggebrecht
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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14
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Hernandez-Martin E, Marcano F, Modroño-Pascual C, Casanova-González O, Plata-Bello J, González-Mora JL. Is it possible to measure hemodynamic changes in the prefrontal cortex through the frontal sinus using continuous wave DOT systems? BIOMEDICAL OPTICS EXPRESS 2019; 10:817-837. [PMID: 30800517 PMCID: PMC6377888 DOI: 10.1364/boe.10.000817] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 12/11/2018] [Accepted: 12/23/2018] [Indexed: 05/20/2023]
Abstract
The present work shows the capability of near infrared (NIR) light to reach the cerebral cortex through the frontal sinus using continuous-wave techniques (CW-DOT) in a dual study. On the one hand, changes in time during the tracking of a blood dye in the prefrontal cortex were monitored. On the other hand, hemodynamic changes induced by low frequency of transcranial magnetic stimulation applied on the prefrontal cortex were recorded. The results show how NIR light projected through the frontal sinus reaches the cerebral cortex target, providing enough information to have a reliable measurement of cortical hemodynamic changes using CW-DOT.
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15
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Machado A, Cai Z, Pellegrino G, Marcotte O, Vincent T, Lina JM, Kobayashi E, Grova C. Optimal positioning of optodes on the scalp for personalized functional near-infrared spectroscopy investigations. J Neurosci Methods 2018; 309:91-108. [PMID: 30107210 DOI: 10.1016/j.jneumeth.2018.08.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Revised: 08/07/2018] [Accepted: 08/08/2018] [Indexed: 12/21/2022]
Abstract
BACKGROUND Application of functional Near InfraRed Spectroscopy (fNIRS) in neurology is still limited as a good optical coupling and optimized optode coverage of specific brain regions remains challenging, notably for prolonged monitoring. METHODS We propose to evaluate a new procedure allowing accurate investigation of specific brain regions. The procedure consists in: (i) A priori maximization of spatial sensitivity of fNIRS measurements targeting specific brain regions, while reducing the number of applied optodes in order to decrease installation time and improve subject comfort. (ii) Utilization of a 3D neuronavigation device and usage of collodion to glue optodes on the scalp, ensuring good optical contact for prolonged investigations. (iii) Local reconstruction of the hemodynamic activity along the cortical surface using inverse modelling. RESULTS Using realistic simulations, we demonstrated that maps derived from optimal montage acquisitions showed, after reconstruction, spatial resolution only slightly lower to that of ultra high density montages while significantly reducing the number of optodes. The optimal montages provided overall good quantitative accuracy especially at the peak of the spatially reconstructed map. We also evaluated real motor responses in two healthy subjects and obtained reproducible motor responses over different sessions. COMPARISON WITH EXISTING METHODS We are among the first to propose a mathematical optimization strategy, allowing high sensitivity measurements. CONCLUSIONS Our results support that using personalized optimal montages should allow to conduct accurate fNIRS studies in clinical settings and realistic lifestyle conditions.
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Affiliation(s)
- A Machado
- Multimodal Functional Imaging Laboratory, Biomedical Engineering Department, McGill University, Canada.
| | - Z Cai
- Physics Department and PERFORM center, Concordia University, Montreal, Canada
| | - G Pellegrino
- Multimodal Functional Imaging Laboratory, Biomedical Engineering Department, McGill University, Canada; IRCCS Fondazione Ospedale San Camillo Via Alberoni, Venice, Italy
| | - O Marcotte
- GERAD, École des HEC, Montréal, Canada; Département d'informatique, Université du Québec à Montréal, Canada; Centre de Recherches Mathématiques, Université de Montréal, Québec, Canada
| | - T Vincent
- Physics Department and PERFORM center, Concordia University, Montreal, Canada
| | - J-M Lina
- École de technologie supérieure de l'Université du Québec, Canada; Centre de Recherches Mathématiques, Université de Montréal, Québec, Canada
| | - E Kobayashi
- Montreal Neurological Institute, Department of Neurology and Neurosurgery, McGill University, Canada
| | - C Grova
- Multimodal Functional Imaging Laboratory, Biomedical Engineering Department, McGill University, Canada; Physics Department and PERFORM center, Concordia University, Montreal, Canada; Montreal Neurological Institute, Department of Neurology and Neurosurgery, McGill University, Canada; Centre de Recherches Mathématiques, Université de Montréal, Québec, Canada
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16
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Aqil M, Jeong MY. Critical bounds on noise and SNR for robust estimation of real-time brain activity from functional near infra-red spectroscopy. Neuroimage 2018; 176:321-353. [PMID: 29698730 DOI: 10.1016/j.neuroimage.2018.04.042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 03/27/2018] [Accepted: 04/18/2018] [Indexed: 10/17/2022] Open
Abstract
The robust characterization of real-time brain activity carries potential for many applications. However, the contamination of measured signals by various instrumental, environmental, and physiological sources of noise introduces a substantial amount of signal variance and, consequently, challenges real-time estimation of contributions from underlying neuronal sources. Functional near infra-red spectroscopy (fNIRS) is an emerging imaging modality whose real-time potential is yet to be fully explored. The objectives of the current study are to (i) validate a time-dependent linear model of hemodynamic responses in fNIRS, and (ii) test the robustness of this approach against measurement noise (instrumental and physiological) and mis-specification of the hemodynamic response basis functions (amplitude, latency, and duration). We propose a linear hemodynamic model with time-varying parameters, which are estimated (adapted and tracked) using a dynamic recursive least square algorithm. Owing to the linear nature of the activation model, the problem of achieving robust convergence to an accurate estimation of the model parameters is recast as a problem of parameter error stability around the origin. We show that robust convergence of the proposed method is guaranteed in the presence of an acceptable degree of model misspecification and we derive an upper bound on noise under which reliable parameters can still be inferred. We also derived a lower bound on signal-to-noise-ratio over which the reliable parameters can still be inferred from a channel/voxel. Whilst here applied to fNIRS, the proposed methodology is applicable to other hemodynamic-based imaging technologies such as functional magnetic resonance imaging.
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Affiliation(s)
- Muhammad Aqil
- Department of Electrical Engineering, Pakistan Institute of Engineering and Applied Sciences, P. O. 45650, Islamabad, Pakistan.
| | - Myung Yung Jeong
- Department of Cogno-Mechatronics Engineering, Pusan National University, 30 Jangjeon-dong, Geumjeong-gu, Busan 609-735, Republic of Korea.
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17
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Bergonzi KM, Burns-Yocum TM, Bumstead JR, Buckley EM, Mannion PC, Tracy CH, Mennerick E, Ferradal SL, Dehghani H, Eggebrecht AT, Culver JP. Lightweight sCMOS-based high-density diffuse optical tomography. NEUROPHOTONICS 2018; 5:035006. [PMID: 30137925 PMCID: PMC6096280 DOI: 10.1117/1.nph.5.3.035006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2018] [Accepted: 07/25/2018] [Indexed: 05/23/2023]
Abstract
Though optical imaging of human brain function is gaining momentum, widespread adoption is restricted in part by a tradeoff among cap wearability, field of view, and resolution. To increase coverage while maintaining functional magnetic resonance imaging (fMRI)-comparable image quality, optical systems require more fibers. However, these modifications drastically reduce the wearability of the imaging cap. The primary obstacle to optimizing wearability is cap weight, which is largely determined by fiber diameter. Smaller fibers collect less light and lead to challenges in obtaining adequate signal-to-noise ratio. Here, we report on a design that leverages the exquisite sensitivity of scientific CMOS cameras to use fibers with ∼30× smaller cross-sectional area than current high-density diffuse optical tomography (HD-DOT) systems. This superpixel sCMOS DOT (SP-DOT) system uses 200-μm -diameter fibers that facilitate a lightweight, wearable cap. We developed a superpixel algorithm with pixel binning and electronic noise subtraction to provide high dynamic range ( >105 ), high frame rate ( >6 Hz ), and a low effective detectivity threshold ( ∼200 fW/Hz1/2-mm2 ), each comparable with previous HD-DOT systems. To assess system performance, we present retinotopic mapping of the visual cortex ( n=5 subjects). SP-DOT offers a practical solution to providing a wearable, large field-of-view, and high-resolution optical neuroimaging system.
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Affiliation(s)
- Karla M. Bergonzi
- Washington University in St. Louis, Department of Biomedical Engineering, St. Louis, Missouri, United States
| | - Tracy M. Burns-Yocum
- Washington University School of Medicine, Department of Radiology, St. Louis, Missouri, United States
| | - Jonathan R. Bumstead
- Washington University School of Medicine, Department of Radiology, St. Louis, Missouri, United States
| | - Elise M. Buckley
- Washington University School of Medicine, Department of Radiology, St. Louis, Missouri, United States
| | - Patrick C. Mannion
- Washington University School of Medicine, Department of Radiology, St. Louis, Missouri, United States
| | - Christopher H. Tracy
- Washington University School of Medicine, Department of Radiology, St. Louis, Missouri, United States
| | - Eli Mennerick
- Washington University School of Medicine, Department of Radiology, St. Louis, Missouri, United States
| | - Silvina L. Ferradal
- Boston Children’s Hospital, Fetal-Neonatal Neuroimaging and Developmental Science Center, Boston, Massachusetts, United States
| | - Hamid Dehghani
- University of Birmingham, School of Computer Science, Birmingham, United Kingdom
| | - Adam T. Eggebrecht
- Washington University School of Medicine, Department of Radiology, St. Louis, Missouri, United States
| | - Joseph P. Culver
- Washington University in St. Louis, Department of Biomedical Engineering, St. Louis, Missouri, United States
- Washington University School of Medicine, Department of Radiology, St. Louis, Missouri, United States
- Washington University in St. Louis, Department of Physics, St. Louis, Missouri, United States
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18
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Dai X, Zhang T, Yang H, Tang J, Carney PR, Jiang H. Fast noninvasive functional diffuse optical tomography for brain imaging. JOURNAL OF BIOPHOTONICS 2018; 11:e201600267. [PMID: 28696034 DOI: 10.1002/jbio.201600267] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 04/23/2017] [Accepted: 06/29/2017] [Indexed: 05/23/2023]
Abstract
Advances in epilepsy studies have shown that specific changes in hemodynamics precede and accompany seizure onset and propagation. However, it has been challenging to noninvasively detect these changes in real time and in humans, due to the lack of fast functional neuroimaging tools. In this study, we present a functional diffuse optical tomography (DOT) method with the guidance of an anatomical human head atlas for 3-dimensionally mapping the brain in real time. Central to our DOT system is a human head interface coupled with a technique that can incorporate topological information of the brain surface into the DOT image reconstruction. The performance of the DOT system was tested by imaging motor tasks-involved brain activities on N = 6 subjects (3 epilepsy patients and 3 healthy controls). We observed diffuse areas of activations from the reconstructed [HbT] images of patients, relative to more focal activations for healthy subjects. Moreover, significant pretask hemodynamic activations were also seen in the motor cortex of patients, which indicated abnormal activities persistent in the brain of an epilepsy patient. This work demonstrates that fast functional DOT is a valuable tool for noninvasive 3-dimensional mapping of brain hemodynamics.
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Affiliation(s)
- Xianjin Dai
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida
| | - Tao Zhang
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida
| | - Hao Yang
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida
| | - Jianbo Tang
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida
| | - Paul R Carney
- Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Huabei Jiang
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida
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Zimeo Morais GA, Balardin JB, Sato JR. fNIRS Optodes' Location Decider (fOLD): a toolbox for probe arrangement guided by brain regions-of-interest. Sci Rep 2018; 8:3341. [PMID: 29463928 PMCID: PMC5820343 DOI: 10.1038/s41598-018-21716-z] [Citation(s) in RCA: 141] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 01/08/2018] [Indexed: 12/13/2022] Open
Abstract
The employment of functional near-infrared spectroscopy (fNIRS) as a method of brain imaging has increased over the last few years due to its portability, low-cost and robustness to subject movement. Experiments with fNIRS are designed in the face of a limited number of sources and detectors (optodes) to be positioned on selected portion(s) of the scalp. The optodes locations represent an expectation of assessing cortical regions relevant to the experiment’s hypothesis. However, this translation process remains a challenge for fNIRS experimental design. In the present study, we propose an approach that automatically decides the location of fNIRS optodes from a set of predefined positions with the aim of maximizing the anatomical specificity to brain regions-of-interest. The implemented method is based on photon transport simulations on two head atlases. The results are compiled into the publicly available “fNIRS Optodes’ Location Decider” (fOLD). This toolbox is a first-order approach to bring the achieved advancements of parcellation methods and meta-analyses from functional magnetic resonance imaging to more precisely guide the selection of optode positions for fNIRS experiments.
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Affiliation(s)
| | - Joana Bisol Balardin
- Instituto do Cérebro, Hospital Israelita Albert Einstein, 05652-900, São Paulo, Brazil
| | - João Ricardo Sato
- Center for Mathematics Computing and Cognition, Universidade Federal do ABC, 09210-180, São Bernardo do Campo, Brazil
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20
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Yücel MA, Selb JJ, Huppert TJ, Franceschini MA, Boas DA. Functional Near Infrared Spectroscopy: Enabling Routine Functional Brain Imaging. CURRENT OPINION IN BIOMEDICAL ENGINEERING 2017; 4:78-86. [PMID: 29457144 PMCID: PMC5810962 DOI: 10.1016/j.cobme.2017.09.011] [Citation(s) in RCA: 106] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Functional Near-Infrared Spectroscopy (fNIRS) maps human brain function by measuring and imaging local changes in hemoglobin concentrations in the brain that arise from the modulation of cerebral blood flow and oxygen metabolism by neural activity. Since its advent over 20 years ago, researchers have exploited and continuously advanced the ability of near infrared light to penetrate through the scalp and skull in order to non-invasively monitor changes in cerebral hemoglobin concentrations that reflect brain activity. We review recent advances in signal processing and hardware that significantly improve the capabilities of fNIRS by reducing the impact of confounding signals to improve statistical robustness of the brain signals and by enhancing the density, spatial coverage, and wearability of measuring devices respectively. We then summarize the application areas that are experiencing rapid growth as fNIRS begins to enable routine functional brain imaging.
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Affiliation(s)
- Meryem A. Yücel
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Juliette J. Selb
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
- Neurophotonics Center, Biomedical Engineering, Boston University, Boston, MA, USA
| | - Theodore J. Huppert
- Department of Radiology and Bioengineering, University of Pittsburg, Pittsburg, PA, USA
| | - Maria Angela Franceschini
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - David A. Boas
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
- Neurophotonics Center, Biomedical Engineering, Boston University, Boston, MA, USA
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21
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Ding H, He Q, Zhou Y, Dan G, Cui S. An Individual Finger Gesture Recognition System Based on Motion-Intent Analysis Using Mechanomyogram Signal. Front Neurol 2017; 8:573. [PMID: 29167655 PMCID: PMC5682314 DOI: 10.3389/fneur.2017.00573] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2017] [Accepted: 10/12/2017] [Indexed: 12/03/2022] Open
Abstract
Motion-intent-based finger gesture recognition systems are crucial for many applications such as prosthesis control, sign language recognition, wearable rehabilitation system, and human–computer interaction. In this article, a motion-intent-based finger gesture recognition system is designed to correctly identify the tapping of every finger for the first time. Two auto-event annotation algorithms are firstly applied and evaluated for detecting the finger tapping frame. Based on the truncated signals, the Wavelet packet transform (WPT) coefficients are calculated and compressed as the features, followed by a feature selection method that is able to improve the performance by optimizing the feature set. Finally, three popular classifiers including naive Bayes (NBC), K-nearest neighbor (KNN), and support vector machine (SVM) are applied and evaluated. The recognition accuracy can be achieved up to 94%. The design and the architecture of the system are presented with full system characterization results.
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Affiliation(s)
- Huijun Ding
- Guangdong Key Laboratory for Biomedical Measurements and Ultrasound Imaging, School of Biomedical Engineering, Health Science Center, Shenzhen University, Guangdong, China
| | - Qing He
- Guangdong Key Laboratory for Biomedical Measurements and Ultrasound Imaging, School of Biomedical Engineering, Health Science Center, Shenzhen University, Guangdong, China
| | - Yongjin Zhou
- Guangdong Key Laboratory for Biomedical Measurements and Ultrasound Imaging, School of Biomedical Engineering, Health Science Center, Shenzhen University, Guangdong, China
| | - Guo Dan
- Guangdong Key Laboratory for Biomedical Measurements and Ultrasound Imaging, School of Biomedical Engineering, Health Science Center, Shenzhen University, Guangdong, China.,Center for Neurorehabilitation, Shenzhen Institute of Neuroscience, Guangdong, China
| | - Song Cui
- Institute of High Performance Computing, Singapore, Singapore
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22
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Classification of somatosensory cortex activities using fNIRS. Behav Brain Res 2017; 333:225-234. [PMID: 28668280 DOI: 10.1016/j.bbr.2017.06.034] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 06/10/2017] [Accepted: 06/20/2017] [Indexed: 01/08/2023]
Abstract
The ability of the somatosensory cortex in differentiating various tactile sensations is very important for a person to perceive the surrounding environment. In this study, we utilize a lab-made multi-channel functional near-infrared spectroscopy (fNIRS) to discriminate the hemodynamic responses (HRs) of four different tactile stimulations (handshake, ball grasp, poking, and cold temperature) applied to the right hand of eight healthy male subjects. The activated brain areas per stimulation are identified with the t-values between the measured data and the desired hemodynamic response function. Linear discriminant analysis is utilized to classify the acquired data into four classes based on three features (mean, peak value, and skewness) of the associated oxy-hemoglobin (HbO) signals. The HRs evoked by the handshake and poking stimulations showed higher peak values in HbO than the ball grasp and cold temperature stimulations. For comparison purposes, additional two-class classifications of poking vs. temperature and handshake vs. ball grasp were performed. The attained classification accuracies were higher than the corresponding chance levels. Our results indicate that fNIRS can be used as an objective measure discriminating different tactile stimulations from the somatosensory cortex of human brain.
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23
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Hernández-Martin E, Marcano F, Casanova O, Modroño C, Plata-Bello J, González-Mora JL. Comparing diffuse optical tomography and functional magnetic resonance imaging signals during a cognitive task: pilot study. NEUROPHOTONICS 2017; 4:015003. [PMID: 28386575 PMCID: PMC5350545 DOI: 10.1117/1.nph.4.1.015003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Accepted: 02/28/2017] [Indexed: 05/07/2023]
Abstract
Diffuse optical tomography (DOT) measures concentration changes in both oxy- and deoxyhemoglobin providing three-dimensional images of local brain activations. A pilot study, which compares both DOT and functional magnetic resonance imaging (fMRI) volumes through t-maps given by canonical statistical parametric mapping (SPM) processing for both data modalities, is presented. The DOT series were processed using a method that is based on a Bayesian filter application on raw DOT data to remove physiological changes and minimum description length application index to select a number of singular values, which reduce the data dimensionality during image reconstruction and adaptation of DOT volume series to normalized standard space. Therefore, statistical analysis is performed with canonical SPM software in the same way as fMRI analysis is done, accepting DOT volumes as if they were fMRI volumes. The results show the reproducibility and ruggedness of the method to process DOT series on group analysis using cognitive paradigms on the prefrontal cortex. Difficulties such as the fact that scalp-brain distances vary between subjects or cerebral activations are difficult to reproduce due to strategies used by the subjects to solve arithmetic problems are considered. T-images given by fMRI and DOT volume series analyzed in SPM show that at the functional level, both DOT and fMRI measures detect the same areas, although DOT provides complementary information to fMRI signals about cerebral activity.
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Affiliation(s)
- Estefania Hernández-Martin
- Universidad de La Laguna, Faculty of Health Sciences (Medicine Section), Department of Basic Medical Science (Physiology Section), Spain
- Address all correspondence to: Estefania Hernández-Martin, E-mail:
| | - Francisco Marcano
- Universidad de La Laguna, Faculty of Health Sciences (Medicine Section), Department of Basic Medical Science (Physiology Section), Spain
| | - Oscar Casanova
- Universidad de La Laguna, Faculty of Health Sciences (Medicine Section), Department of Basic Medical Science (Physiology Section), Spain
| | - Cristian Modroño
- Universidad de La Laguna, Faculty of Health Sciences (Medicine Section), Department of Basic Medical Science (Physiology Section), Spain
| | - Julio Plata-Bello
- Universidad de La Laguna, Faculty of Health Sciences (Medicine Section), Department of Basic Medical Science (Physiology Section), Spain
| | - Jose Luis González-Mora
- Universidad de La Laguna, Faculty of Health Sciences (Medicine Section), Department of Basic Medical Science (Physiology Section), Spain
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Pollonini L, Bortfeld H, Oghalai JS. PHOEBE: a method for real time mapping of optodes-scalp coupling in functional near-infrared spectroscopy. BIOMEDICAL OPTICS EXPRESS 2016; 7:5104-5119. [PMID: 28018728 PMCID: PMC5175555 DOI: 10.1364/boe.7.005104] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 10/22/2016] [Accepted: 10/31/2016] [Indexed: 05/06/2023]
Abstract
Recent functional near-infrared spectroscopy (fNIRS) instrumentation encompasses several dozen of optodes to enable reconstructing a hemodynamic image of the entire cerebral cortex. Despite its potential clinical applicability, widespread use of fNIRS with human subjects is currently limited by unresolved issues, namely the collection from the entirety of optical channels of signals with a signal-to-noise ratio (SNR) sufficient to carry out a reliable estimation of cortical hemodynamics, and the considerable amount of time that placing numerous optodes take with individuals for whom achieving good optical coupling to the scalp is difficult due to thick or dark hair. To address these issues, we developed a numerical method that: 1) at the channel level, computes an objective measure of the signal-to-noise ratio (SNR) related to its optical coupling to the scalp, akin to electrode conductivity used in electroencephalography (EEG), and 2) at the optode level, determines and displays the coupling status of all individual optodes in real time on a model of a human head. This approach aims to shorten the pre-acquisition preparation time by visually displaying which optodes require further adjustment for optimum scalp coupling, and to maximize the signal-to-noise ratio (SNR) of all optical channels contributing to the functional hemodynamic mapping. The methodology described in this paper has been implemented in a software tool named PHOEBE (placing headgear optodes efficiently before experimentation) that is freely available for use by the fNIRS community.
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Affiliation(s)
- Luca Pollonini
- Department of Engineering Technology, University of Houston, 4734 Calhoun Road, Houston, TX 77204, USA
| | - Heather Bortfeld
- Department of Psychological Sciences, University of California, Merced, 5200 N. Lake Road, Merced, CA 95343, USA
| | - John S. Oghalai
- Department of Otolaryngology - Head and Neck Surgery, Stanford University, 801 Welch Road, Stanford, CA 94305, USA
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25
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Nguyen HD, Hong KS, Shin YI. Bundled-Optode Method in Functional Near-Infrared Spectroscopy. PLoS One 2016; 11:e0165146. [PMID: 27788178 PMCID: PMC5082888 DOI: 10.1371/journal.pone.0165146] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 10/09/2016] [Indexed: 11/18/2022] Open
Abstract
In this paper, a theory for detection of the absolute concentrations of oxy-hemoglobin (HbO) and deoxy-hemoglobin (HbR) from hemodynamic responses using a bundled-optode configuration in functional near-infrared spectroscopy (fNIRS) is proposed. The proposed method is then applied to the identification of two fingers (i.e., little and thumb) during their flexion and extension. This experiment involves a continuous-wave-type dual-wavelength (760 and 830 nm) fNIRS and five healthy male subjects. The active brain locations of two finger movements are identified based on the analysis of the t- and p-values of the averaged HbOs, which are quite distinctive. Our experimental results, furthermore, revealed that the hemodynamic responses of two-finger movements are different: The mean, peak, and time-to-peak of little finger movements are higher than those of thumb movements. It is noteworthy that the developed method can be extended to 3-dimensional fNIRS imaging.
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Affiliation(s)
- Hoang-Dung Nguyen
- Department of Cogno-Mechatronics Engineering, Pusan National University, 2 Busandaehak-ro, Geumjeong-gu, Busan, 46241, Republic of Korea
| | - Keum-Shik Hong
- Department of Cogno-Mechatronics Engineering, Pusan National University, 2 Busandaehak-ro, Geumjeong-gu, Busan, 46241, Republic of Korea
- School of Mechanical Engineering, Pusan National University, 2 Busandaehak-ro, Geumjeong-gu, Busan, 46241, Republic of Korea
- * E-mail:
| | - Yong-Il Shin
- Department of Rehabilitation Medicine, School of Medicine, Pusan National University & Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, 20, Geumo-ro, Mulgeum-eup, Yangsan-si, Gyeongsangnam-do, 50612, Republic of Korea
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26
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Chitnis D, Cooper RJ, Dempsey L, Powell S, Quaggia S, Highton D, Elwell C, Hebden JC, Everdell NL. Functional imaging of the human brain using a modular, fibre-less, high-density diffuse optical tomography system. BIOMEDICAL OPTICS EXPRESS 2016; 7:4275-4288. [PMID: 27867731 PMCID: PMC5102535 DOI: 10.1364/boe.7.004275] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 08/25/2016] [Accepted: 09/06/2016] [Indexed: 05/21/2023]
Abstract
We present the first three-dimensional, functional images of the human brain to be obtained using a fibre-less, high-density diffuse optical tomography system. Our technology consists of independent, miniaturized, silicone-encapsulated DOT modules that can be placed directly on the scalp. Four of these modules were arranged to provide up to 128, dual-wavelength measurement channels over a scalp area of approximately 60 × 65 mm2. Using a series of motor-cortex stimulation experiments, we demonstrate that this system can obtain high-quality, continuous-wave measurements at source-detector separations ranging from 14 to 55 mm in adults, in the presence of hair. We identify robust haemodynamic response functions in 5 out of 5 subjects, and present diffuse optical tomography images that depict functional haemodynamic responses that are well-localized in all three dimensions at both the individual and group levels. This prototype modular system paves the way for a new generation of wearable, wireless, high-density optical neuroimaging technologies.
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27
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Nguyen HD, Hong KS. Bundled-optode implementation for 3D imaging in functional near-infrared spectroscopy. BIOMEDICAL OPTICS EXPRESS 2016; 7:3491-3507. [PMID: 27699115 PMCID: PMC5030027 DOI: 10.1364/boe.7.003491] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 08/04/2016] [Accepted: 08/10/2016] [Indexed: 05/03/2023]
Abstract
The paper presents a functional near-infrared spectroscopy (fNIRS)-based bundled-optode method for detection of the changes of oxy-hemoglobin (HbO) and deoxy-hemoglobin (HbR) concentrations. fNIRS with 32 optodes is utilized to measure five healthy male subjects' brain-hemodynamic responses to arithmetic tasks. Specifically, the coordinates of 256 voxels in the three-dimensional (3D) volume are computed according to the known probe geometry. The mean path length factor in the Beer-Lambert equation is estimated as a function of the emitter-detector distance, which is utilized for computation of the absorption coefficient. The mean values of HbO and HbR obtained from the absorption coefficient are then applied for construction of a 3D fNIRS image. Our results show that the proposed method, as compared with the conventional approach, can detect brain activity with higher spatial resolution. This method can be extended for 3D fNIRS imaging in real-time applications.
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Affiliation(s)
- Hoang-Dung Nguyen
- Department of Cogno-Mechatronics Engineering, Pusan National University, 2 Busandaehak-ro, Geumjeong-gu, Busan 46241, South Korea
| | - Keum-Shik Hong
- Department of Cogno-Mechatronics Engineering, Pusan National University, 2 Busandaehak-ro, Geumjeong-gu, Busan 46241, South Korea
- School of Mechanical Engineering, Pusan National University, 2 Busandaehak-ro, Geumjeong-gu, Busan 46241, South Korea
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Hoshi Y, Yamada Y. Overview of diffuse optical tomography and its clinical applications. JOURNAL OF BIOMEDICAL OPTICS 2016; 21:091312. [PMID: 27420810 DOI: 10.1117/1.jbo.21.9.091312] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 06/13/2016] [Indexed: 05/23/2023]
Abstract
Near-infrared diffuse optical tomography (DOT), one of the most sophisticated optical imaging techniques for observations through biological tissue, allows 3-D quantitative imaging of optical properties, which include functional and anatomical information. With DOT, it is expected to be possible to overcome the limitations of conventional near-infrared spectroscopy (NIRS) as well as offering the potential for diagnostic optical imaging. However, DOT has been under development for more than 30 years, and the difficulties in development are attributed to the fact that light is strongly scattered and that diffusive photons are used for the image reconstruction. The DOT algorithm is based on the techniques of inverse problems. The radiative transfer equation accurately describes photon propagation in biological tissue, while, because of its high computation load, the diffusion equation (DE) is often used as the forward model. However, the DE is invalid in low-scattering and/or highly absorbing regions and in the vicinity of light sources. The inverse problem is inherently ill-posed and highly undetermined. Here, we first summarize NIRS and then describe various approaches in the efforts to develop accurate and efficient DOT algorithms and present some examples of clinical applications. Finally, we discuss the future prospects of DOT.
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Affiliation(s)
- Yoko Hoshi
- Hamamatsu University School of Medicine, Department of Biomedical Optics, Institute for Medical Photonics Research, Preeminent Medical Photonics Education and Research Center, 1-20-1 Handayama, Higashi-ku, Hamamatsu 431-3192, Japan
| | - Yukio Yamada
- University of Electro-Communications, Brain Science Inspired Life Support Research Center, 1-5-1 Chofugaoka, Chofu, Tokyo 182-8585, Japan
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Shimokawa T, Ishii T, Takahashi Y, Sugawara S, Sato MA, Yamashita O. Diffuse optical tomography using multi-directional sources and detectors. BIOMEDICAL OPTICS EXPRESS 2016; 7:2623-40. [PMID: 27446694 PMCID: PMC4948618 DOI: 10.1364/boe.7.002623] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 06/01/2016] [Accepted: 06/13/2016] [Indexed: 05/24/2023]
Abstract
Diffuse optical tomography (DOT) is an advanced imaging method used to visualize the internal state of biological tissues as 3D images. However, current continuous-wave DOT requires high-density probe arrays for measurement (less than 15-mm interval) to gather enough information for 3D image reconstruction, which makes the experiment time-consuming. In this paper, we propose a novel DOT measurement system using multi-directional light sources and multi-directional photodetectors instead of high-density probe arrays. We evaluated this system's multi-directional DOT through computer simulation and a phantom experiment. From the results, we achieved DOT with less than 5-mm localization error up to a 15-mm depth with low-density probe arrays (30-mm interval), indicating that the multi-directional measurement approach allows DOT without requiring high-density measurement.
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Affiliation(s)
- Takeaki Shimokawa
- ATR Neural Information Analysis Laboratories, Kyoto 619-0288, Japan
- These authors contributed equally to this work
| | - Toshihiro Ishii
- Ricoh Institute of Future Technology, RICOH Company Ltd., Miyagi 981-1241, Japan
- These authors contributed equally to this work
| | - Yoichiro Takahashi
- Ricoh Institute of Future Technology, RICOH Company Ltd., Miyagi 981-1241, Japan
| | - Satoru Sugawara
- Ricoh Institute of Future Technology, RICOH Company Ltd., Miyagi 981-1241, Japan
| | - Masa-aki Sato
- ATR Neural Information Analysis Laboratories, Kyoto 619-0288, Japan
| | - Okito Yamashita
- ATR Neural Information Analysis Laboratories, Kyoto 619-0288, Japan
- Brain Functional Imaging Technologies Group, CiNet, Osaka 565-0871, Japan
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30
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Vidal-Rosas EE, Billings SA, Chico T, Coca D. Reproducibility of parameters of postocclusive reactive hyperemia measured by diffuse optical tomography. JOURNAL OF BIOMEDICAL OPTICS 2016; 21:66012. [PMID: 27304420 DOI: 10.1117/1.jbo.21.6.066012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Accepted: 05/09/2016] [Indexed: 06/06/2023]
Abstract
The application of near-infrared spectroscopy (NIRS) to assess microvascular function has shown promising results. An important limitation when using a single source-detector pair, however, is the lack of depth sensitivity. Diffuse optical tomography (DOT) overcomes this limitation using an array of sources and detectors that allow the reconstruction of volumetric hemodynamic changes. This study compares the key parameters of postocclusive reactive hyperemia measured in the forearm using standard NIRS and DOT. We show that while the mean parameter values are similar for the two techniques, DOT achieves much better reproducibility, as measured by the intraclass correlation coefficient (ICC). We show that DOT achieves high reproducibility for muscle oxygen consumption (ICC: 0.99), time to maximal HbO2 (ICC: 0.94), maximal HbO2 (ICC: 0.99), and time to maximal HbT (ICC: 0.99). Absolute reproducibility as measured by the standard error of measurement is consistently smaller and close to zero (ideal value) across all parameters measured by DOT compared to NIRS. We conclude that DOT provides a more robust characterization of the reactive hyperemic response and show how the availability of volumetric hemodynamic changes allows the identification of areas of temporal consistency, which could help characterize more precisely the microvasculature.
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Affiliation(s)
- Ernesto E Vidal-Rosas
- University of Sheffield, Department of Automatic Control and Systems Engineering, Mappin Street, Sheffield S1 3JD, United Kingdom
| | - Stephen A Billings
- University of Sheffield, Department of Automatic Control and Systems Engineering, Mappin Street, Sheffield S1 3JD, United Kingdom
| | - Timothy Chico
- University of Sheffield, Department of Cardiovascular Science, Western Bank, Sheffield S10 2TF, United Kingdom
| | - Daniel Coca
- University of Sheffield, Department of Automatic Control and Systems Engineering, Mappin Street, Sheffield S1 3JD, United Kingdom
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Brigadoi S, Powell S, Cooper RJ, Dempsey LA, Arridge S, Everdell N, Hebden J, Gibson AP. Evaluating real-time image reconstruction in diffuse optical tomography using physiologically realistic test data. BIOMEDICAL OPTICS EXPRESS 2015; 6:4719-4737. [PMID: 26713189 PMCID: PMC4679249 DOI: 10.1364/boe.6.004719] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Revised: 11/01/2015] [Accepted: 11/03/2015] [Indexed: 05/30/2023]
Abstract
In diffuse optical tomography (DOT), real-time image reconstruction of oxy- and deoxy-haemoglobin changes occurring in the brain could give valuable information in clinical care settings. Although non-linear reconstruction techniques could provide more accurate results, their computational burden makes them unsuitable for real-time applications. Linear techniques can be employed under the assumption that the expected change in absorption is small. Several approaches exist, differing primarily in their handling of regularization and the noise statistics. In real experiments, it is impossible to compute the true noise statistics, because of the presence of physiological oscillations in the measured data. This is even more critical in real-time applications, where no off-line filtering and averaging can be performed to reduce the noise level. Therefore, many studies substitute the noise covariance matrix with the identity matrix. In this paper, we examined two questions: does using the noise model with realistic, imperfect data yield an improvement in image quality compared to using the identity matrix; and what is the difference in quality between online and offline reconstructions. Bespoke test data were created using a novel process through which simulated changes in absorption were added to real resting-state DOT data. A realistic multi-layer head model was used as the geometry for the reconstruction. Results validated our assumptions, highlighting the validity of computing the noise statistics from the measured data for online image reconstruction, which was performed at 2 Hz. Our results can be directly extended to a real application where real-time imaging is required.
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Affiliation(s)
- Sabrina Brigadoi
- Department of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT,
UK
| | - Samuel Powell
- Department of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT,
UK
- Department of Computer Science, University College London, London WC1E 6BT,
UK
| | - Robert J. Cooper
- Department of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT,
UK
| | - Laura A. Dempsey
- Department of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT,
UK
| | - Simon Arridge
- Department of Computer Science, University College London, London WC1E 6BT,
UK
| | - Nick Everdell
- Department of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT,
UK
| | - Jeremy Hebden
- Department of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT,
UK
| | - Adam P. Gibson
- Department of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT,
UK
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Konecky SD, Wilson RH, Hagen N, Mazhar A, Tkaczyk TS, Frostig RD, Tromberg BJ. Hyperspectral optical tomography of intrinsic signals in the rat cortex. NEUROPHOTONICS 2015; 2:045003. [PMID: 26835483 PMCID: PMC4718192 DOI: 10.1117/1.nph.2.4.045003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Accepted: 10/19/2015] [Indexed: 05/20/2023]
Abstract
We introduce a tomographic approach for three-dimensional imaging of evoked hemodynamic activity, using broadband illumination and diffuse optical tomography (DOT) image reconstruction. Changes in diffuse reflectance in the rat somatosensory cortex due to stimulation of a single whisker were imaged at a frame rate of 5 Hz using a hyperspectral image mapping spectrometer. In each frame, images in 38 wavelength bands from 484 to 652 nm were acquired simultaneously. For data analysis, we developed a hyperspectral DOT algorithm that used the Rytov approximation to quantify changes in tissue concentration of oxyhemoglobin ([Formula: see text]) and deoxyhemoglobin (ctHb) in three dimensions. Using this algorithm, the maximum changes in [Formula: see text] and ctHb were found to occur at [Formula: see text] and [Formula: see text] beneath the surface of the cortex, respectively. Rytov tomographic reconstructions revealed maximal spatially localized increases and decreases in [Formula: see text] and ctHb of [Formula: see text] and [Formula: see text], respectively, with these maximum changes occurring at [Formula: see text] poststimulus. The localized optical signals from the Rytov approximation were greater than those from modified Beer-Lambert, likely due in part to the inability of planar reflectance to account for partial volume effects.
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Affiliation(s)
- Soren D. Konecky
- University of California, Irvine, Beckman Laser Institute and Medical Clinic, Laser Microbeam and Medical Program, 1002 Health Sciences Road, Irvine, California 92612, United States
| | - Robert H. Wilson
- University of California, Irvine, Beckman Laser Institute and Medical Clinic, Laser Microbeam and Medical Program, 1002 Health Sciences Road, Irvine, California 92612, United States
| | - Nathan Hagen
- Rice University, Department of Biomedical Engineering, 6500 Main Street, Houston, Texas 77030, United States
| | - Amaan Mazhar
- University of California, Irvine, Beckman Laser Institute and Medical Clinic, Laser Microbeam and Medical Program, 1002 Health Sciences Road, Irvine, California 92612, United States
- University of California, Irvine, Department of Biomedical Engineering, 5200 Engineering Hall, Irvine, California 92697, United States
| | - Tomasz S. Tkaczyk
- Rice University, Department of Biomedical Engineering, 6500 Main Street, Houston, Texas 77030, United States
| | - Ron D. Frostig
- University of California, Irvine, Department of Neurobiology and Behavior, 2205 McGaugh Hall, Irvine, California 92697, United States
- University of California, Irvine, Department of Biomedical Engineering, 5200 Engineering Hall, Irvine, California 92697, United States
| | - Bruce J. Tromberg
- University of California, Irvine, Beckman Laser Institute and Medical Clinic, Laser Microbeam and Medical Program, 1002 Health Sciences Road, Irvine, California 92612, United States
- University of California, Irvine, Department of Biomedical Engineering, 5200 Engineering Hall, Irvine, California 92697, United States
- Address all correspondence to: Bruce J. Tromberg, E-mail:
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Drenckhahn C, Koch SP, Dümmler J, Kohl-Bareis M, Steinbrink J, Dreier JP. A validation study of the use of near-infrared spectroscopy imaging in primary and secondary motor areas of the human brain. Epilepsy Behav 2015; 49:118-25. [PMID: 25976181 DOI: 10.1016/j.yebeh.2015.04.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 04/03/2015] [Indexed: 10/23/2022]
Abstract
The electroencephalographically measured Bereitschafts (readiness)-potential in the supplementary motor area (SMA) serves as a signature of the preparation of motor activity. Using a multichannel, noninvasive near-infrared spectroscopy (NIRS) imager, we studied the vascular correlate of the readiness potential. Sixteen healthy subjects performed a self-paced or externally triggered motor task in a single or repetitive pattern, while NIRS simultaneously recorded the task-related responses of deoxygenated hemoglobin (HbR) in the primary motor area (M1) and the SMA. Right-hand movements in the repetitive sequence trial elicited a significantly greater HbR response in both the SMA and the left M1 compared to left-hand movements. During the single sequence condition, the HbR response in the SMA, but not in the M1, was significantly greater for self-paced than for externally cued movements. Nonetheless, an unequivocal temporal delay was not found between the SMA and M1. Near-infrared spectroscopy is a promising, noninvasive bedside tool for the neuromonitoring of epileptic seizures or cortical spreading depolarizations (CSDs) in patients with epilepsy, stroke, or brain trauma because these pathological events are associated with typical spatial and temporal changes in HbR. Propagation is a characteristic feature of these events which importantly supports their identification and characterization in invasive recordings. Unfortunately, the present noninvasive study failed to show a temporal delay during self-paced movements between the SMA and M1 as a vascular correlate of the readiness potential. Although this result does not exclude, in principle, the possibility that scalp-NIRS can detect a temporal delay between different regions during epileptic seizures or CSDs, it strongly suggests that further technological development of NIRS should focus on both improved spatial and temporal resolution. This article is part of a Special Issue entitled Status Epilepticus.
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Affiliation(s)
- Christoph Drenckhahn
- Center for Stroke Research Berlin, Charité University Medicine Berlin, Berlin, Germany; Department of Neurology, Charité University Medicine Berlin, Berlin, Germany; Berlin Neuroimaging Center, Charité University Medicine Berlin, Berlin, Germany
| | - Stefan P Koch
- Berlin Neuroimaging Center, Charité University Medicine Berlin, Berlin, Germany
| | - Johannes Dümmler
- Department of Anaesthesiology and Intensive Care Medicine, Christian-Albrechts University, Kiel, Germany
| | | | - Jens Steinbrink
- Center for Stroke Research Berlin, Charité University Medicine Berlin, Berlin, Germany; Berlin Neuroimaging Center, Charité University Medicine Berlin, Berlin, Germany
| | - Jens P Dreier
- Center for Stroke Research Berlin, Charité University Medicine Berlin, Berlin, Germany; Department of Neurology, Charité University Medicine Berlin, Berlin, Germany; Department of Experimental Neurology, Charité University Medicine Berlin, Berlin, Germany; Berlin Neuroimaging Center, Charité University Medicine Berlin, Berlin, Germany.
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Wu X, Eggebrecht AT, Ferradal SL, Culver JP, Dehghani H. Evaluation of rigid registration methods for whole head imaging in diffuse optical tomography. NEUROPHOTONICS 2015; 2:035002. [PMID: 26217675 PMCID: PMC4509792 DOI: 10.1117/1.nph.2.3.035002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 06/18/2015] [Indexed: 05/22/2023]
Abstract
Functional brain imaging has become an important neuroimaging technique for the study of brain organization and development. Compared to other imaging techniques, diffuse optical tomography (DOT) is a portable and low-cost technique that can be applied to infants and hospitalized patients using an atlas-based light model. For DOT imaging, the accuracy of the forward model has a direct effect on the resulting recovered brain function within a field of view and so the accuracy of the spatially normalized atlas-based forward models must be evaluated. Herein, the accuracy of atlas-based DOT is evaluated on models that are spatially normalized via a number of different rigid registration methods on 24 subjects. A multileveled approach is developed to evaluate the correlation of the geometrical and sensitivity accuracies across the full field of view as well as within specific functional subregions. Results demonstrate that different registration methods are optimal for recovery of different sets of functional brain regions. However, the "nearest point to point" registration method, based on the EEG 19 landmark system, is shown to be the most appropriate registration method for image quality throughout the field of view of the high-density cap that covers the whole of the optically accessible cortex.
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Affiliation(s)
- Xue Wu
- University of Birmingham, School of Computer Science, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Adam T. Eggebrecht
- Washington University School of Medicine, Department of Radiology, 4525 Scott Avenue, St. Louis, Missouri 63110, United States
| | - Silvina L. Ferradal
- Fetal-Neonatal Neuroimaging and Developmental Science Center, Boston Children’s Hospital, 300 Longwood Avenue, Boston, Massachusetts 02115, United States
| | - Joseph P. Culver
- Washington University School of Medicine, Department of Radiology, 4525 Scott Avenue, St. Louis, Missouri 63110, United States
- Washington University, Department of Biomedical Engineering, One Brookings Drive, St. Louis, Missouri 63130, United States
| | - Hamid Dehghani
- University of Birmingham, School of Computer Science, Edgbaston, Birmingham B15 2TT, United Kingdom
- Address all correspondence to: Hamid Dehghani, E-mail:
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Molteni E, Arrigoni F, Bardoni A, Galbiati S, Villa F, Colombo K, Strazzer S. Bedside assessment of residual functional activation in minimally conscious state using NIRS and general linear models. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2015; 2013:3551-4. [PMID: 24110496 DOI: 10.1109/embc.2013.6610309] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Near Infrared Spectroscopy (NIRS) was employed for the detection of possible residual functional activations in two patients in minimally conscious state. An "ad hoc" protocol for somatosensory and motor stimulations was created and administered to the patients, synchronously to NIRS recordings. One healthy subject was also assessed with the same task for comparison. Results from the healthy subject globally agree with the literature. Moreover, we could obtain significant results from the patients data. Indeed, in one patient, the NIRS channels showing activation completely correspond to regions of residual cortex underneath. In the second patient, though, together with possible residual intact cortex insulae, some channels match large cystic formations, with fluid gathering.
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36
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Dewey RS, Hartley DEH. Cortical cross-modal plasticity following deafness measured using functional near-infrared spectroscopy. Hear Res 2015; 325:55-63. [PMID: 25819496 DOI: 10.1016/j.heares.2015.03.007] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Revised: 03/17/2015] [Accepted: 03/17/2015] [Indexed: 10/23/2022]
Abstract
Evidence from functional neuroimaging studies suggests that the auditory cortex can become more responsive to visual and somatosensory stimulation following deafness, and that this occurs predominately in the right hemisphere. Extensive cross-modal plasticity in prospective cochlear implant recipients is correlated with poor speech outcomes following implantation, highlighting the potential impact of central auditory plasticity on subsequent aural rehabilitation. Conversely, the effects of hearing restoration with a cochlear implant on cortical plasticity are less well understood, since the use of most neuroimaging techniques in CI recipients is either unsafe or problematic due to the electromagnetic artefacts generated by CI stimulation. Additionally, techniques such as functional magnetic resonance imaging (fMRI) are confounded by acoustic noise produced by the scanner that will be perceived more by hearing than by deaf individuals. Subsequently it is conceivable that auditory responses to acoustic noise produced by the MR scanner may mask auditory cortical responses to non-auditory stimulation, and render inter-group comparisons less significant. Uniquely, functional near-infrared spectroscopy (fNIRS) is a silent neuroimaging technique that is non-invasive and completely unaffected by the presence of a CI. Here, we used fNIRS to study temporal-lobe responses to auditory, visual and somatosensory stimuli in thirty profoundly-deaf participants and thirty normally-hearing controls. Compared with silence, acoustic noise stimuli elicited a significant group fNIRS response in the temporal region of normally-hearing individuals, which was not seen in profoundly-deaf participants. Visual motion elicited a larger group response within the right temporal lobe of profoundly-deaf participants, compared with normally-hearing controls. However, bilateral temporal lobe fNIRS activation to somatosensory stimulation was comparable in both groups. Using fNIRS these results confirm that auditory deprivation is associated with cross-modal plasticity of visual inputs to auditory cortex. Although we found no evidence for plasticity of somatosensory inputs, it is possible that our recordings may have included activation of somatosensory cortex that masked any group differences in auditory cortical responses due to the limited spatial resolution associated with fNIRS.
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Affiliation(s)
- Rebecca S Dewey
- Otology and Hearing Group, Division of Clinical Neuroscience, School of Medicine, University of Nottingham, Nottingham, NG7 2UH, UK; National Institute for Health Research (NIHR) Nottingham Hearing Biomedical Research Unit, 113 The Ropewalk, Nottingham, NG1 5DU, UK.
| | - Douglas E H Hartley
- Otology and Hearing Group, Division of Clinical Neuroscience, School of Medicine, University of Nottingham, Nottingham, NG7 2UH, UK; National Institute for Health Research (NIHR) Nottingham Hearing Biomedical Research Unit, 113 The Ropewalk, Nottingham, NG1 5DU, UK; MRC Institute of Hearing Research, University Park, Nottingham, NG7 2RD, UK.
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37
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Aqil M, Jeong MY, Hong KS, Ge SS. Upper bounds on noise and model misspecification for robust estimation of real-time brain activity from functional near infrared spectroscopy. Neuroimage 2015:S1053-8119(15)00188-3. [PMID: 25783206 DOI: 10.1016/j.neuroimage.2015.03.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Revised: 02/25/2015] [Accepted: 03/03/2015] [Indexed: 10/23/2022] Open
Abstract
The robust characterization of real-time brain activity carries potential for many applications. However, the contamination of measured signals by various instrumental, environmental, and physiological sources of noise introduces a substantial amount of signal variance and, consequently, challenges real-time estimation of contributions from underlying neuronal sources. Functional near infrared spectroscopy (fNIRS) is an emerging imaging modality whose real-time potential is yet to be fully explored. The objectives of the current study are to (i) validate a time-dependent linear model of hemodynamic responses in fNIRS, and (ii) test the robustness of this approach against measurement noise (instrumental and physiological) and mis-specification of the hemodynamic response basis functions (amplitude, latency, and duration). We propose a linear hemodynamic model with time-varying parameters, which are estimated (adapted and tracked) using a dynamic recursive least square algorithm. Owing to the linear nature of the activation model, the problem of achieving robust convergence to an accurate estimation of the model parameters is recast as a problem of parameter error stability around the origin. We show that robust convergence of the proposed method is guaranteed in the presence of an acceptable degree of model misspecification and we derive an upper bound on noise under which reliable parameters can still be inferred. While here applied to fNIRS, the proposed methodology is applicable to other hemodynamic-based imaging technologies such as functional magnetic resonance imaging.
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Affiliation(s)
- Muhammad Aqil
- Department of Electrical Engineering, Pakistan Institute of Engineering and Applied Sciences, P. O. 45650, Islamabad, Pakistan; Department of Cogno-Mechatronics Engineering, Pusan National University, 30 Jangjeon-dong, Geumjeong-gu, Busan 609-735, Republic of Korea.
| | - Myung-Yung Jeong
- Department of Cogno-Mechatronics Engineering, Pusan National University, 30 Jangjeon-dong, Geumjeong-gu, Busan 609-735, Republic of Korea.
| | - Keum-Shik Hong
- Department of Cogno-Mechatronics Engineering, Pusan National University, 30 Jangjeon-dong, Geumjeong-gu, Busan 609-735, Republic of Korea.
| | - Shuzhi Sam Ge
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117576, Singapore.
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Ferradal SL, Liao SM, Eggebrecht AT, Shimony JS, Inder TE, Culver JP, Smyser CD. Functional Imaging of the Developing Brain at the Bedside Using Diffuse Optical Tomography. Cereb Cortex 2015; 26:1558-68. [PMID: 25595183 DOI: 10.1093/cercor/bhu320] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
While histological studies and conventional magnetic resonance imaging (MRI) investigations have elucidated the trajectory of structural changes in the developing brain, less is known regarding early functional cerebral development. Recent investigations have demonstrated that resting-state functional connectivity MRI (fcMRI) can identify networks of functional cerebral connections in infants. However, technical and logistical challenges frequently limit the ability to perform MRI scans early or repeatedly in neonates, particularly in those at greatest risk for adverse neurodevelopmental outcomes. High-density diffuse optical tomography (HD-DOT), a portable imaging modality, potentially enables early continuous and quantitative monitoring of brain function in infants. We introduce an HD-DOT imaging system that combines advancements in cap design, ergonomics, and data analysis methods to allow bedside mapping of functional brain development in infants. In a cohort of healthy, full-term neonates scanned within the first days of life, HD-DOT results demonstrate strong congruence with those obtained using co-registered, subject-matched fcMRI and reflect patterns of typical brain development. These findings represent a transformative advance in functional neuroimaging in infants, and introduce HD-DOT as a powerful and practical method for quantitative mapping of early functional brain development in normal and high-risk neonates.
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Affiliation(s)
- Silvina L Ferradal
- Department of Biomedical Engineering, Washington University, St Louis, MO, USA Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, MO, USA
| | - Steve M Liao
- Department of Pediatrics, Washington University School of Medicine, St Louis, MO, USA
| | - Adam T Eggebrecht
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, MO, USA
| | - Joshua S Shimony
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, MO, USA
| | - Terrie E Inder
- Department of Pediatric Newborn Medicine, Brigham and Women's Hospital, Boston, MA, USA
| | - Joseph P Culver
- Department of Biomedical Engineering, Washington University, St Louis, MO, USA Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, MO, USA
| | - Christopher D Smyser
- Department of Pediatrics, Washington University School of Medicine, St Louis, MO, USA Department of Neurology, Washington University School of Medicine, St Louis, MO, USA
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Zhang T, Zhou J, Carney PR, Jiang H. Towards real-time detection of seizures in awake rats with GPU-accelerated diffuse optical tomography. J Neurosci Methods 2014; 240:28-36. [PMID: 25445250 DOI: 10.1016/j.jneumeth.2014.10.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Revised: 09/06/2014] [Accepted: 10/21/2014] [Indexed: 01/17/2023]
Abstract
BACKGROUND Advancement in clinically relevant studies like seizure interruption using functional neuro imaging tools has shown that specific changes in hemodynamics precede and accompany seizure onset and propagation. However, preclinical seizure experiments need to be conducted in awake animals with images reconstructed and displayed in real-time. METHODS This article describes an approach that can be utilized to tackle these challenges. A subject specific head interface and restraining method was designed to allow for DOT to imaging of hemodynamic changes in unanesthetized rats during evoked acute seizures. Using CUDA programming model, the finite-element based nonlinear iterative algorithm for image reconstruction was parallelized. RESULTS Early hemodynamic changes were monitored in real time and observed tens of seconds prior to seizure onset. Utilizing the massive parallelization offered by graphic processing units (GPU), DOT was extended to online image reconstruction within 1s. COMPARISON WITH EXISTING METHODS Pre-seizure state related hemodynamic changes were detected in awake rats. 3D monitoring of hemodynamic changes was performed in real time with our parallelized image reconstruction procedure. CONCLUSION Diffuse optical tomography (DOT) is a promising neuroimaging tool for the investigation of seizures in awake animals.
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Affiliation(s)
- Tao Zhang
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL 32611, USA
| | - Junli Zhou
- Department of Pediatrics, University of Florida, Gainesville, FL 32611, USA
| | - Paul R Carney
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL 32611, USA; Department of Pediatrics, University of Florida, Gainesville, FL 32611, USA; Department of Neurology, University of Florida, Gainesville, FL 32611, USA; Department of Neuroscience, University of Florida, Gainesville, FL 32611, USA
| | - Huabei Jiang
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL 32611, USA.
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Wu X, Eggebrecht AT, Ferradal SL, Culver JP, Dehghani H. Quantitative evaluation of atlas-based high-density diffuse optical tomography for imaging of the human visual cortex. BIOMEDICAL OPTICS EXPRESS 2014; 5:3882-900. [PMID: 25426318 PMCID: PMC4242025 DOI: 10.1364/boe.5.003882] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Revised: 08/21/2014] [Accepted: 09/25/2014] [Indexed: 05/24/2023]
Abstract
Image recovery in diffuse optical tomography (DOT) of the human brain often relies on accurate models of light propagation within the head. In the absence of subject specific models for image reconstruction, the use of atlas based models are showing strong promise. Although there exists some understanding in the use of some limited rigid model registrations in DOT, there has been a lack of a detailed analysis between errors in geometrical accuracy, light propagation in tissue and subsequent errors in dynamic imaging of recovered focal activations in the brain. In this work 11 different rigid registration algorithms, across 24 simulated subjects, are evaluated for DOT studies in the visual cortex. Although there exists a strong correlation (R(2) = 0.97) between geometrical surface error and internal light propagation errors, the overall variation is minimal when analysing recovered focal activations in the visual cortex. While a subject specific mesh gives the best results with a 1.2 mm average location error, no single algorithm provides errors greater than 4.5 mm. This work demonstrates that the use of rigid algorithms for atlas based imaging is a promising route when subject specific models are not available.
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Affiliation(s)
- Xue Wu
- School of Computer Science, University of Birmingham, Birmingham, B15 2TT,
UK
| | - Adam T. Eggebrecht
- Department of Radiology, Washington University School of Medicine, 4525 Scott Avenue, St Louis, MO, 63110,
USA
| | - Silvina L Ferradal
- Department of Radiology, Washington University School of Medicine, 4525 Scott Avenue, St Louis, MO, 63110,
USA
- Department of Biomedical Engineering, Washington University, One Brookings Drive, St. Louis, MO, 63130,
USA
| | - Joseph P. Culver
- Department of Radiology, Washington University School of Medicine, 4525 Scott Avenue, St Louis, MO, 63110,
USA
- Department of Biomedical Engineering, Washington University, One Brookings Drive, St. Louis, MO, 63130,
USA
| | - Hamid Dehghani
- School of Computer Science, University of Birmingham, Birmingham, B15 2TT,
UK
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41
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Aqil M, Jeong MY, Hong KS, Ge SS. WITHDRAWN: Robustness bound on noises with mis-modeling errors for signified brain imaging in real-time. Neuroimage 2014:S1053-8119(14)00767-8. [PMID: 25241906 DOI: 10.1016/j.neuroimage.2014.09.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Revised: 06/07/2014] [Accepted: 09/10/2014] [Indexed: 11/29/2022] Open
Abstract
This article has been withdrawn at the request of the author(s) and/or editor. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at http://www.elsevier.com/locate/withdrawalpolicy.
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Affiliation(s)
- Muhammad Aqil
- Department of Electrical Engineering, Pakistan Institute of Engineering and Applied Sciences, P. O. 45650, Islamabad, Pakistan; Department of Cogno-Mechatronics Engineering, Pusan National University, 30 Jangjeon-dong, Geumjeong-gu, Busan 609-735, Republic of Korea.
| | - Myung-Yung Jeong
- Department of Cogno-Mechatronics Engineering, Pusan National University, 30 Jangjeon-dong, Geumjeong-gu, Busan 609-735, Republic of Korea.
| | - Keum-Shik Hong
- Department of Cogno-Mechatronics Engineering, Pusan National University, 30 Jangjeon-dong, Geumjeong-gu, Busan 609-735, Republic of Korea.
| | - Shuzhi Sam Ge
- Department of Cogno-Mechatronics Engineering, Pusan National University, 30 Jangjeon-dong, Geumjeong-gu, Busan 609-735, Republic of Korea; Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117576.
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Habermehl C, Steinbrink J, Müller KR, Haufe S. Optimizing the regularization for image reconstruction of cerebral diffuse optical tomography. JOURNAL OF BIOMEDICAL OPTICS 2014; 19:96006. [PMID: 25208243 DOI: 10.1117/1.jbo.19.9.096006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Accepted: 07/24/2014] [Indexed: 05/20/2023]
Abstract
Functional near-infrared spectroscopy (fNIRS) is an optical method for noninvasively determining brain activation by estimating changes in the absorption of near-infrared light. Diffuse optical tomography (DOT) extends fNIRS by applying overlapping “high density” measurements, and thus providing a three-dimensional imaging with an improved spatial resolution. Reconstructing brain activation images with DOT requires solving an underdetermined inverse problem with far more unknowns in the volume than in the surface measurements. All methods of solving this type of inverse problem rely on regularization and the choice of corresponding regularization or convergence criteria. While several regularization methods are available, it is unclear how well suited they are for cerebral functional DOT in a semi-infinite geometry. Furthermore, the regularization parameter is often chosen without an independent evaluation, and it may be tempting to choose the solution that matches a hypothesis and rejects the other. In this simulation study, we start out by demonstrating how the quality of cerebral DOT reconstructions is altered with the choice of the regularization parameter for different methods. To independently select the regularization parameter, we propose a cross-validation procedure which achieves a reconstruction quality close to the optimum. Additionally, we compare the outcome of seven different image reconstruction methods for cerebral functional DOT. The methods selected include reconstruction procedures that are already widely used for cerebral DOT [minimum l2-norm estimate (l2MNE) and truncated singular value decomposition], recently proposed sparse reconstruction algorithms [minimum l1- and a smooth minimum l0-norm estimate (l1MNE, l0MNE, respectively)] and a depth- and noise-weighted minimum norm (wMNE). Furthermore, we expand the range of algorithms for DOT by adapting two EEG-source localization algorithms [sparse basis field expansions and linearly constrained minimum variance (LCMV) beamforming]. Independent of the applied noise level, we find that the LCMV beamformer is best for single spot activations with perfect location and focality of the results, whereas the minimum l1-norm estimate succeeds with multiple targets.
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Affiliation(s)
- Christina Habermehl
- Berlin Institute of Technology, Department of Computer Science, Machine Learning Group, Marchstraße 23, Berlin 10587, GermanybBernstein Focus Neurotechnology, Department of Computer Science, Marchstraße 23, Berlin 10587, GermanycCharité University Medicin
| | - Jens Steinbrink
- Bernstein Focus Neurotechnology, Department of Computer Science, Marchstraße 23, Berlin 10587, GermanydCharité University Medicine, Center for Stroke Research, Charitéplatz 1, Berlin 10117, Germany
| | - Klaus-Robert Müller
- Berlin Institute of Technology, Department of Computer Science, Machine Learning Group, Marchstraße 23, Berlin 10587, GermanybBernstein Focus Neurotechnology, Department of Computer Science, Marchstraße 23, Berlin 10587, GermanyeBernstein Center for Compu
| | - Stefan Haufe
- Berlin Institute of Technology, Department of Computer Science, Machine Learning Group, Marchstraße 23, Berlin 10587, GermanybBernstein Focus Neurotechnology, Department of Computer Science, Marchstraße 23, Berlin 10587, Germany
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Bogler C, Mehnert J, Steinbrink J, Haynes JD. Decoding vigilance with NIRS. PLoS One 2014; 9:e101729. [PMID: 25032963 PMCID: PMC4102486 DOI: 10.1371/journal.pone.0101729] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Accepted: 06/11/2014] [Indexed: 11/19/2022] Open
Abstract
Sustained, long-term cognitive workload is associated with variations and decrements in performance. Such fluctuations in vigilance can be a risk factor especially during dangerous attention demanding activities. Functional MRI studies have shown that attentional performance is correlated with BOLD-signals, especially in parietal and prefrontal cortical regions. An interesting question is whether these BOLD-signals could be measured in real-world scenarios, say to warn in a dangerous workplace whenever a subjects' vigilance is low. Because fMRI lacks the mobility needed for such applications, we tested whether the monitoring of vigilance might be possible using Near-Infrared Spectroscopy (NIRS). NIRS is a highly mobile technique that measures hemodynamics in the surface of the brain. We demonstrate that non-invasive NIRS signals correlate with vigilance. These signals carry enough information to decode subjects' reaction times at a single trial level.
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Affiliation(s)
- Carsten Bogler
- Bernstein Center for Computational Neuroscience Berlin and Charité – Universitätsmedizin Berlin, Berlin, Germany
- Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
- Department of Neurology, Otto-von-Guericke University Magdeburg, Magdeburg, Germany
- * E-mail: (CB); (J-DH)
| | - Jan Mehnert
- Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
- Berlin NeuroImaging Center, Charité - Universitätsmedizin Berlin, Berlin, Germany
- Department of Machine Learning, Institute of Technology, Berlin, Germany
| | - Jens Steinbrink
- Berlin NeuroImaging Center, Charité - Universitätsmedizin Berlin, Berlin, Germany
- Center for Stroke Research Berlin, Charité - Universitätsmedizin Berlin, Berlin, Germany
- Bernstein Focus Neurotechnology Berlin, Berlin Institute of Technology, Berlin, Germany
| | - John-Dylan Haynes
- Bernstein Center for Computational Neuroscience Berlin and Charité – Universitätsmedizin Berlin, Berlin, Germany
- Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
- Department of Neurology, Otto-von-Guericke University Magdeburg, Magdeburg, Germany
- * E-mail: (CB); (J-DH)
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Brigadoi S, Aljabar P, Kuklisova-Murgasova M, Arridge SR, Cooper RJ. A 4D neonatal head model for diffuse optical imaging of pre-term to term infants. Neuroimage 2014; 100:385-94. [PMID: 24954280 DOI: 10.1016/j.neuroimage.2014.06.028] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Revised: 05/23/2014] [Accepted: 06/09/2014] [Indexed: 10/25/2022] Open
Abstract
Diffuse optical tomography is most accurate when an individual's MRI data can be used as a spatial prior for image reconstruction and for visualization of the resulting images of changes in oxy- and deoxy-hemoglobin concentration. As this necessitates an MRI scan to be performed for each study, which undermines many of the advantages of diffuse optical methods, the use of registered atlases to model the individual's anatomy is becoming commonplace. Infant studies require carefully age-matched atlases because of the rapid growth and maturation of the infant brain. In this paper, we present a 4D neonatal head model which, for each week from 29 to 44 weeks post-menstrual age, includes: 1) a multi-layered tissue mask which identifies extra-cerebral layers, cerebrospinal fluid, gray matter, white matter, cerebellum and brainstem, 2) a high-density tetrahedral head mesh, 3) surface meshes for the scalp, gray-matter and white matter layers and 4) cranial landmarks and 10-5 locations on the scalp surface. This package, freely available online at www.ucl.ac.uk/medphys/research/4dneonatalmodel can be applied by users of near-infrared spectroscopy and diffuse optical tomography to optimize probe locations, optimize image reconstruction, register data to cortical locations and ultimately improve the accuracy and interpretation of diffuse optical techniques in newborn populations.
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Affiliation(s)
- Sabrina Brigadoi
- Department of Developmental Psychology, University of Padova, Italy.
| | - Paul Aljabar
- Centre for the Developing Brain and Department of Biomedical Engineering, Division of Imaging Sciences, King's College London, UK
| | - Maria Kuklisova-Murgasova
- Centre for the Developing Brain and Department of Biomedical Engineering, Division of Imaging Sciences, King's College London, UK
| | - Simon R Arridge
- Department of Computer Science, University College London, UK
| | - Robert J Cooper
- Biomedical Optics Research Laboratory, Department of Medical Physics and Bioengineering, University College London, UK
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45
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Lin ZJ, Li L, Cazzell M, Liu H. Atlas-guided volumetric diffuse optical tomography enhanced by generalized linear model analysis to image risk decision-making responses in young adults. Hum Brain Mapp 2014; 35:4249-66. [PMID: 24619964 PMCID: PMC4282392 DOI: 10.1002/hbm.22459] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2013] [Revised: 11/25/2013] [Accepted: 12/18/2013] [Indexed: 11/06/2022] Open
Abstract
Diffuse optical tomography (DOT) is a variant of functional near infrared spectroscopy and has the capability of mapping or reconstructing three dimensional (3D) hemodynamic changes due to brain activity. Common methods used in DOT image analysis to define brain activation have limitations because the selection of activation period is relatively subjective. General linear model (GLM)-based analysis can overcome this limitation. In this study, we combine the atlas-guided 3D DOT image reconstruction with GLM-based analysis (i.e., voxel-wise GLM analysis) to investigate the brain activity that is associated with risk decision-making processes. Risk decision-making is an important cognitive process and thus is an essential topic in the field of neuroscience. The Balloon Analog Risk Task (BART) is a valid experimental model and has been commonly used to assess human risk-taking actions and tendencies while facing risks. We have used the BART paradigm with a blocked design to investigate brain activations in the prefrontal and frontal cortical areas during decision-making from 37 human participants (22 males and 15 females). Voxel-wise GLM analysis was performed after a human brain atlas template and a depth compensation algorithm were combined to form atlas-guided DOT images. In this work, we wish to demonstrate the excellence of using voxel-wise GLM analysis with DOT to image and study cognitive functions in response to risk decision-making. Results have shown significant hemodynamic changes in the dorsal lateral prefrontal cortex (DLPFC) during the active-choice mode and a different activation pattern between genders; these findings correlate well with published literature in functional magnetic resonance imaging (fMRI) and fNIRS studies.
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Affiliation(s)
- Zi-Jing Lin
- Department of Bioengineering, Joint Program of Biomedical Engineering between University of Texas at Arlington and University of Texas Southwestern Medical Center at Dallas, University of Texas at Arlington, Arlington, Texas; National Synchrotron Radiation Research Center, Hsinchu, Taiwan
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Scholkmann F, Kleiser S, Metz AJ, Zimmermann R, Mata Pavia J, Wolf U, Wolf M. A review on continuous wave functional near-infrared spectroscopy and imaging instrumentation and methodology. Neuroimage 2014; 85 Pt 1:6-27. [PMID: 23684868 DOI: 10.1016/j.neuroimage.2013.05.004] [Citation(s) in RCA: 1000] [Impact Index Per Article: 100.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Revised: 04/12/2013] [Accepted: 05/03/2013] [Indexed: 01/09/2023] Open
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Perdue KL, Diamond SG. Effects of spatial pattern scale of brain activity on the sensitivity of DOT, fMRI, EEG and MEG. PLoS One 2013; 8:e83299. [PMID: 24376684 PMCID: PMC3871678 DOI: 10.1371/journal.pone.0083299] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2013] [Accepted: 11/06/2013] [Indexed: 11/18/2022] Open
Abstract
The objective of this work is to quantify how patterns of cortical activity at different spatial scales are measured by noninvasive functional neuroimaging sensors. We simulated cortical activation patterns at nine different spatial scales in a realistic head model and propagated this activity to magnetoencephalography (MEG), electroencephalography (EEG), diffuse optical tomography (DOT), and functional magnetic resonance imaging (fMRI) sensors in arrangements that are typically used in functional neuroimaging studies. We estimated contrast transfer functions (CTF), correlation distances in sensor space, and the minimum resolvable spatial scale of cortical activity for each modality. We found that CTF decreases as the spatial extent of cortical activity decreases, and that correlations between nearby sensors depend on the spatial extent of cortical activity. For cortical activity on the intermediate spatial scale of 6.7 cm(2), the correlation distances (r>0.5) were 1.0 cm for fMRI, 2.0 cm for DOT, 12.8 for EEG, 9.5 cm for MEG magnetometers and 9.7 cm for MEG gradiometers. The resolvable spatial pattern scale was found to be 1.43 cm(2) for MEG magnetometers, 0.88 cm(2) for MEG gradiometers, 376 cm(2) for EEG, 0.75 cm(2) for DOT, and 0.072 cm(2) for fMRI. These findings show that sensitivity to cortical activity varies substantially as a function of spatial scale within and between the different imaging modalities. This information should be taken into account when interpreting neuroimaging data and when choosing the number of nodes for network analyses in sensor space.
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Affiliation(s)
- Katherine L. Perdue
- Thayer School of Engineering at Dartmouth, Hanover, New Hampshire, United States of America
- * E-mail:
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48
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Tian F, Liu H. Depth-compensated diffuse optical tomography enhanced by general linear model analysis and an anatomical atlas of human head. Neuroimage 2013; 85 Pt 1:166-80. [PMID: 23859922 DOI: 10.1016/j.neuroimage.2013.07.016] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Revised: 05/24/2013] [Accepted: 07/04/2013] [Indexed: 11/17/2022] Open
Abstract
One of the main challenges in functional diffuse optical tomography (DOT) is to accurately recover the depth of brain activation, which is even more essential when differentiating true brain signals from task-evoked artifacts in the scalp. Recently, we developed a depth-compensated algorithm (DCA) to minimize the depth localization error in DOT. However, the semi-infinite model that was used in DCA deviated significantly from the realistic human head anatomy. In the present work, we incorporated depth-compensated DOT (DC-DOT) with a standard anatomical atlas of human head. Computer simulations and human measurements of sensorimotor activation were conducted to examine and prove the depth specificity and quantification accuracy of brain atlas-based DC-DOT. In addition, node-wise statistical analysis based on the general linear model (GLM) was also implemented and performed in this study, showing the robustness of DC-DOT that can accurately identify brain activation at the correct depth for functional brain imaging, even when co-existing with superficial artifacts.
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Affiliation(s)
- Fenghua Tian
- Department of Bioengineering, Joint Program in Biomedical Engineering between UT Arlington and UT Southwestern Medical Center at Dallas, University of Texas at Arlington, Arlington, TX, USA
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A wearable multi-channel fNIRS system for brain imaging in freely moving subjects. Neuroimage 2013; 85 Pt 1:64-71. [PMID: 23810973 DOI: 10.1016/j.neuroimage.2013.06.062] [Citation(s) in RCA: 228] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Revised: 06/19/2013] [Accepted: 06/20/2013] [Indexed: 11/21/2022] Open
Abstract
Functional near infrared spectroscopy (fNIRS) is a versatile neuroimaging tool with an increasing acceptance in the neuroimaging community. While often lauded for its portability, most of the fNIRS setups employed in neuroscientific research still impose usage in a laboratory environment. We present a wearable, multi-channel fNIRS imaging system for functional brain imaging in unrestrained settings. The system operates without optical fiber bundles, using eight dual wavelength light emitting diodes and eight electro-optical sensors, which can be placed freely on the subject's head for direct illumination and detection. Its performance is tested on N=8 subjects in a motor execution paradigm performed under three different exercising conditions: (i) during outdoor bicycle riding, (ii) while pedaling on a stationary training bicycle, and (iii) sitting still on the training bicycle. Following left hand gripping, we observe a significant decrease in the deoxyhemoglobin concentration over the contralateral motor cortex in all three conditions. A significant task-related ΔHbO2 increase was seen for the non-pedaling condition. Although the gross movements involved in pedaling and steering a bike induced more motion artifacts than carrying out the same task while sitting still, we found no significant differences in the shape or amplitude of the HbR time courses for outdoor or indoor cycling and sitting still. We demonstrate the general feasibility of using wearable multi-channel NIRS during strenuous exercise in natural, unrestrained settings and discuss the origins and effects of data artifacts. We provide quantitative guidelines for taking condition-dependent signal quality into account to allow the comparison of data across various levels of physical exercise. To the best of our knowledge, this is the first demonstration of functional NIRS brain imaging during an outdoor activity in a real life situation in humans.
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Hassanpour MS, White BR, Eggebrecht AT, Ferradal SL, Snyder AZ, Culver JP. Statistical analysis of high density diffuse optical tomography. Neuroimage 2013; 85 Pt 1:104-16. [PMID: 23732886 DOI: 10.1016/j.neuroimage.2013.05.105] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2013] [Revised: 05/03/2013] [Accepted: 05/21/2013] [Indexed: 11/30/2022] Open
Abstract
High density diffuse optical tomography (HD-DOT) is a noninvasive neuroimaging modality with moderate spatial resolution and localization accuracy. Due to portability and wear-ability advantages, HD-DOT has the potential to be used in populations that are not amenable to functional magnetic resonance imaging (fMRI), such as hospitalized patients and young children. However, whereas the use of event-related stimuli designs, general linear model (GLM) analysis, and imaging statistics are standardized and routine with fMRI, such tools are not yet common practice in HD-DOT. In this paper we adapt and optimize fundamental elements of fMRI analysis for application to HD-DOT. We show the use of event-related protocols and GLM de-convolution analysis in un-mixing multi-stimuli event-related HD-DOT data. Statistical parametric mapping (SPM) in the framework of a general linear model is developed considering the temporal and spatial characteristics of HD-DOT data. The statistical analysis utilizes a random field noise model that incorporates estimates of the local temporal and spatial correlations of the GLM residuals. The multiple-comparison problem is addressed using a cluster analysis based on non-stationary Gaussian random field theory. These analysis tools provide access to a wide range of experimental designs necessary for the study of the complex brain functions. In addition, they provide a foundation for understanding and interpreting HD-DOT results with quantitative estimates for the statistical significance of detected activation foci.
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Affiliation(s)
- Mahlega S Hassanpour
- Department of Physics, CB 1105, Washington University in St. Louis, One Brookings Drive, St. Louis, MO 63130-4899, USA; Department of Radiology, CB 8225, Washington University School of Medicine, 4525 Scott Ave., St. Louis, MO 63110, USA
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