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Ioussoufovitch S, Diop M. Time-domain diffuse optical imaging technique for monitoring rheumatoid arthritis disease activity: theoretical development and in silico validation. Phys Med Biol 2024; 69:125022. [PMID: 38830363 DOI: 10.1088/1361-6560/ad539f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Accepted: 06/03/2024] [Indexed: 06/05/2024]
Abstract
Objective.Effective early treatment-within 3-5 months of disease onset-significantly improves rheumatoid arthritis (RA) prognosis. Nevertheless, 1 in 3 patients experiences treatment failure which takes 3-6 months to detect with current monitoring techniques. The aim of this work is to develop a method for extracting quantitative features from data obtained with time-domain diffuse optical imaging (TD-DOI), and demonstrate their sensitivity to RA disease activity.Approach.80 virtual phantoms of the proximal interphalangeal joint-obtained from a realistic tissue distribution derived from magnetic resonance imaging-were created to simulate RA-induced alterations in 5 physiological parameters. TD-DOI images were generated using Monte Carlo simulations, and Poisson noise was added to each image. Subsequently, each image was convolved with an instrument response function (IRF) to mimic experimental measurements. Various spatiotemporal features were extracted from the images (i.e. statistical moments, temporal Fourier components), corrected for IRF effects, and correlated with the disease index (DI) of each phantom.Main results.Spatiotemporal Fourier components of TD-DOI images were highly correlated with DI despite the confounding effects of noise and the IRF. Moreover, lower temporal frequency components (⩽0.4 GHz) demonstrated greater sensitivity to small changes in disease activity than previously published spatial features extracted from the same images.Significance.Spatiotemporal components of TD-DOI images may be more sensitive to small changes in RA disease activity than previously reported DOI features. TD-DOI may enable earlier detection of RA treatment failure, which would reduce the time needed to identify treatment failure and improve patient prognosis.
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Affiliation(s)
- S Ioussoufovitch
- School of Biomedical Engineering, Western University and Collaborative Training Program in Musculoskeletal Health Research, Bone & Joint Institute, Western University, 1151 Richmond St., London, Canada
| | - M Diop
- School of Biomedical Engineering, Western University and Collaborative Training Program in Musculoskeletal Health Research, Bone & Joint Institute, Western University, 1151 Richmond St., London, Canada
- Imaging Program, Lawson Health Research Institute, 268 Grosvenor St., London, Canada
- Department of Medical Biophysics, Western University, 1151 Richmond St., London, Canada
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2
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Li NC, Ioussoufovitch S, Diop M. HyperTRCSS: A hyperspectral time-resolved compressive sensing spectrometer for depth-sensitive monitoring of cytochrome-c-oxidase and blood oxygenation. JOURNAL OF BIOMEDICAL OPTICS 2024; 29:015002. [PMID: 38269084 PMCID: PMC10807872 DOI: 10.1117/1.jbo.29.1.015002] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/23/2023] [Revised: 12/21/2023] [Accepted: 01/04/2024] [Indexed: 01/26/2024]
Abstract
Significance Hyperspectral time-resolved (TR) near-infrared spectroscopy offers the potential to monitor cytochrome-c-oxidase (oxCCO) and blood oxygenation in the adult brain with minimal scalp/skull contamination. We introduce a hyperspectral TR spectrometer that uses compressive sensing to minimize acquisition time without compromising spectral range or resolution and demonstrate oxCCO and blood oxygenation monitoring in deep tissue. Aim Develop a hyperspectral TR compressive sensing spectrometer and use it to monitor oxCCO and blood oxygenation in deep tissue. Approach Homogeneous tissue-mimicking phantom experiments were conducted to confirm the spectrometer's sensitivity to oxCCO and blood oxygenation. Two-layer phantoms were used to evaluate the spectrometer's sensitivity to oxCCO and blood oxygenation in the bottom layer through a 10 mm thick static top layer. Results The spectrometer was sensitive to oxCCO and blood oxygenation changes in the bottom layer of the two-layer phantoms, as confirmed by concomitant measurements acquired directly from the bottom layer. Measures of oxCCO and blood oxygenation by the spectrometer were highly correlated with "gold standard" measures in the homogeneous and two-layer phantom experiments. Conclusions The results show that the hyperspectral TR compressive sensing spectrometer is sensitive to changes in oxCCO and blood oxygenation in deep tissue through a thick static top layer.
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Affiliation(s)
- Natalie C. Li
- Western University, School of Biomedical Engineering, Faculty of Engineering, London, Ontario, Canada
| | - Seva Ioussoufovitch
- Western University, School of Biomedical Engineering, Faculty of Engineering, London, Ontario, Canada
| | - Mamadou Diop
- Western University, School of Biomedical Engineering, Faculty of Engineering, London, Ontario, Canada
- Western University, Schulich School of Medicine and Dentistry, Department of Medical Biophysics, London, Ontario, Canada
- Lawson Health Research Institute, Imaging Program, London, Ontario, Canada
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3
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Ioussoufovitch S, Cohen DJF, Milej D, Diop M. Compressed sensing time-resolved spectrometer for quantification of light absorbers in turbid media. BIOMEDICAL OPTICS EXPRESS 2021; 12:6442-6460. [PMID: 34745748 PMCID: PMC8547999 DOI: 10.1364/boe.433427] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 08/20/2021] [Accepted: 09/10/2021] [Indexed: 06/13/2023]
Abstract
Time-resolved (TR) spectroscopy is well-suited to address the challenges of quantifying light absorbers in highly scattering media such as living tissue; however, current TR spectrometers are either based on expensive array detectors or rely on wavelength scanning. Here, we introduce a TR spectrometer architecture based on compressed sensing (CS) and time-correlated single-photon counting. Using both CS and basis scanning, we demonstrate that-in homogeneous and two-layer tissue-mimicking phantoms made of Intralipid and Indocyanine Green-the CS method agrees with or outperforms uncompressed approaches. Further, we illustrate the superior depth sensitivity of TR spectroscopy and highlight the potential of the device to quantify absorption changes in deeper (>1 cm) tissue layers.
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Affiliation(s)
- Seva Ioussoufovitch
- Western University, Faculty of Engineering, School of Biomedical Engineering, Collaborative Training Program in Musculoskeletal Health Research, Bone & Joint Institute, 1151 Richmond St., London, N6A 5C1, Canada
| | - David Jonathan Fulop Cohen
- Western University, Schulich School of Medicine & Dentistry, Department of Medical Biophysics, 1151 Richmond St., London, N6A 5C1, Canada
| | - Daniel Milej
- Western University, Schulich School of Medicine & Dentistry, Department of Medical Biophysics, 1151 Richmond St., London, N6A 5C1, Canada
- Lawson Health Research Institute, Imaging Program, 268 Grosvenor St., London, N6A 4V2, Canada
| | - Mamadou Diop
- Western University, Faculty of Engineering, School of Biomedical Engineering, Collaborative Training Program in Musculoskeletal Health Research, Bone & Joint Institute, 1151 Richmond St., London, N6A 5C1, Canada
- Western University, Schulich School of Medicine & Dentistry, Department of Medical Biophysics, 1151 Richmond St., London, N6A 5C1, Canada
- Lawson Health Research Institute, Imaging Program, 268 Grosvenor St., London, N6A 4V2, Canada
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4
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The Use of Supercontinuum Laser Sources in Biomedical Diffuse Optics: Unlocking the Power of Multispectral Imaging. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11104616] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Optical techniques based on diffuse optics have been around for decades now and are making their way into the day-to-day medical applications. Even though the physics foundations of these techniques have been known for many years, practical implementation of these technique were hindered by technological limitations, mainly from the light sources and/or detection electronics. In the past 20 years, the developments of supercontinuum laser (SCL) enabled to unlock some of these limitations, enabling the development of system and methodologies relevant for medical use, notably in terms of spectral monitoring. In this review, we focus on the use of SCL in biomedical diffuse optics, from instrumentation and methods developments to their use for medical applications. A total of 95 publications were identified, from 1993 to 2021. We discuss the advantages of the SCL to cover a large spectral bandwidth with a high spectral power and fast switching against the disadvantages of cost, bulkiness, and long warm up times. Finally, we summarize the utility of using such light sources in the development and application of diffuse optics in biomedical sciences and clinical applications.
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5
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Raiko J, Koskensalo K, Sainio T. Imaging-based internal body temperature measurements: The journal Temperature toolbox. Temperature (Austin) 2020; 7:363-388. [PMID: 33251282 PMCID: PMC7678923 DOI: 10.1080/23328940.2020.1769006] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 05/08/2020] [Accepted: 05/11/2020] [Indexed: 12/27/2022] Open
Abstract
Noninvasive imaging methods of internal body temperature are in high demand in both clinical medicine and physiological research. Thermography and thermometry can be used to assess tissue temperature during thermal therapies: ablative and hyperthermia treatments to ensure adequate temperature rise in target tissues but also to avoid collateral damage by heating healthy tissues. In research use, measurement of internal body temperature enables us the production of thermal maps on muscles, internal organs, and other tissues of interest. The most used methods for noninvasive imaging of internal body temperature are based on different parameters acquired with magnetic resonance imaging, ultrasound, computed tomography, microwave radiometry, photoacoustic imaging, and near-infrared spectroscopy. In the current review, we examine the aforementioned imaging methods, their use in estimating internal body temperature in vivo with their advantages and disadvantages, and the physical phenomena the thermography or thermometry modalities are based on.
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Affiliation(s)
- Juho Raiko
- Turku PET Centre, University of Turku, Turku, Finland
- Department of Nutrition and Movement Sciences, Maastricht University, Maastricht, The Netherlands
| | - Kalle Koskensalo
- Department of Medical Physics, Turku University Hospital, Turku, Finland
| | - Teija Sainio
- Department of Medical Physics, Turku University Hospital, Turku, Finland
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6
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Abdalmalak A, Milej D, Yip LCM, Khan AR, Diop M, Owen AM, St Lawrence K. Assessing Time-Resolved fNIRS for Brain-Computer Interface Applications of Mental Communication. Front Neurosci 2020; 14:105. [PMID: 32132894 PMCID: PMC7040089 DOI: 10.3389/fnins.2020.00105] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 01/27/2020] [Indexed: 12/13/2022] Open
Abstract
Brain-computer interfaces (BCIs) are becoming increasingly popular as a tool to improve the quality of life of patients with disabilities. Recently, time-resolved functional near-infrared spectroscopy (TR-fNIRS) based BCIs are gaining traction because of their enhanced depth sensitivity leading to lower signal contamination from the extracerebral layers. This study presents the first account of TR-fNIRS based BCI for “mental communication” on healthy participants. Twenty-one (21) participants were recruited and were repeatedly asked a series of questions where they were instructed to imagine playing tennis for “yes” and to stay relaxed for “no.” The change in the mean time-of-flight of photons was used to calculate the change in concentrations of oxy- and deoxyhemoglobin since it provides a good compromise between depth sensitivity and signal-to-noise ratio. Features were extracted from the average oxyhemoglobin signals to classify them as “yes” or “no” responses. Linear-discriminant analysis (LDA) and support vector machine (SVM) classifiers were used to classify the responses using the leave-one-out cross-validation method. The overall accuracies achieved for all participants were 75% and 76%, using LDA and SVM, respectively. The results also reveal that there is no significant difference in accuracy between questions. In addition, physiological parameters [heart rate (HR) and mean arterial pressure (MAP)] were recorded on seven of the 21 participants during motor imagery (MI) and rest to investigate changes in these parameters between conditions. No significant difference in these parameters was found between conditions. These findings suggest that TR-fNIRS could be suitable as a BCI for patients with brain injuries.
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Affiliation(s)
- Androu Abdalmalak
- Department of Medical Biophysics, Western University, London, ON, Canada.,Imaging Program, Lawson Health Research Institute, London, ON, Canada
| | - Daniel Milej
- Department of Medical Biophysics, Western University, London, ON, Canada.,Imaging Program, Lawson Health Research Institute, London, ON, Canada
| | - Lawrence C M Yip
- Department of Medical Biophysics, Western University, London, ON, Canada.,Imaging Program, Lawson Health Research Institute, London, ON, Canada
| | - Ali R Khan
- Department of Medical Biophysics, Western University, London, ON, Canada.,Imaging Research Laboratories, Robarts Research Institute, London, ON, Canada
| | - Mamadou Diop
- Department of Medical Biophysics, Western University, London, ON, Canada.,Imaging Program, Lawson Health Research Institute, London, ON, Canada
| | - Adrian M Owen
- Brain and Mind Institute, Western University, London, ON, Canada
| | - Keith St Lawrence
- Department of Medical Biophysics, Western University, London, ON, Canada.,Imaging Program, Lawson Health Research Institute, London, ON, Canada
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7
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Doulgerakis M, Eggebrecht AT, Dehghani H. High-density functional diffuse optical tomography based on frequency-domain measurements improves image quality and spatial resolution. NEUROPHOTONICS 2019; 6:035007. [PMID: 31482102 PMCID: PMC6702521 DOI: 10.1117/1.nph.6.3.035007] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 07/30/2019] [Indexed: 05/18/2023]
Abstract
Measurements of dynamic near-infrared (NIR) light attenuation across the human head together with model-based image reconstruction algorithms allow the recovery of three-dimensional spatial brain activation maps. Previous studies using high-density diffuse optical tomography (HD-DOT) systems have reported improved image quality over sparse arrays. These HD-DOT systems incorporated multidistance overlapping continuous wave measurements that only recover differential intensity attenuation. We investigate the potential improvement in reconstructed image quality due to the additional incorporation of phase shift measurements, which reflect the time-of-flight of the measured NIR light, within the tomographic reconstruction from high-density measurements. To evaluate image reconstruction with and without the additional phase information, we simulated point spread functions across a whole-scalp field of view in 24 subject-specific anatomical models using an experimentally derived noise model. The addition of phase information improves the image quality by reducing localization error by up to 59% and effective resolution by up to 21% as compared to using the intensity attenuation measurements alone. Furthermore, we demonstrate that the phase data enable images to be resolved at deeper brain regions where intensity data fail, which is further supported by utilizing experimental data from a single subject measurement during a retinotopic experiment.
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Affiliation(s)
- Matthaios Doulgerakis
- University of Birmingham, School of Computer Science, Birmingham, England, United Kingdom
| | - Adam T. Eggebrecht
- Washington University School of Medicine, Mallinckrodt Institute of Radiology, St. Louis, Missouri, United States
| | - Hamid Dehghani
- University of Birmingham, School of Computer Science, Birmingham, England, United Kingdom
- Address all correspondence to Hamid Dehghani, E-mail:
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8
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Rupawala M, Dehghani H, Lucas SJE, Tino P, Cruse D. Shining a Light on Awareness: A Review of Functional Near-Infrared Spectroscopy for Prolonged Disorders of Consciousness. Front Neurol 2018; 9:350. [PMID: 29872420 PMCID: PMC5972220 DOI: 10.3389/fneur.2018.00350] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 04/30/2018] [Indexed: 12/19/2022] Open
Abstract
Qualitative clinical assessments of the recovery of awareness after severe brain injury require an assessor to differentiate purposeful behavior from spontaneous behavior. As many such behaviors are minimal and inconsistent, behavioral assessments are susceptible to diagnostic errors. Advanced neuroimaging tools can bypass behavioral responsiveness and reveal evidence of covert awareness and cognition within the brains of some patients, thus providing a means for more accurate diagnoses, more accurate prognoses, and, in some instances, facilitated communication. The majority of reports to date have employed the neuroimaging methods of functional magnetic resonance imaging, positron emission tomography, and electroencephalography (EEG). However, each neuroimaging method has its own advantages and disadvantages (e.g., signal resolution, accessibility, etc.). Here, we describe a burgeoning technique of non-invasive optical neuroimaging—functional near-infrared spectroscopy (fNIRS)—and review its potential to address the clinical challenges of prolonged disorders of consciousness. We also outline the potential for simultaneous EEG to complement the fNIRS signal and suggest the future directions of research that are required in order to realize its clinical potential.
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Affiliation(s)
- Mohammed Rupawala
- Centre for Doctoral Training in Physical Sciences for Health, University of Birmingham, Birmingham, United Kingdom
| | - Hamid Dehghani
- Centre for Doctoral Training in Physical Sciences for Health, University of Birmingham, Birmingham, United Kingdom.,School of Computer Science, University of Birmingham, Birmingham, United Kingdom
| | - Samuel J E Lucas
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Peter Tino
- School of Computer Science, University of Birmingham, Birmingham, United Kingdom
| | - Damian Cruse
- School of Psychology, University of Birmingham, Birmingham, United Kingdom
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9
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Wojtkiewicz S, Durduran T, Dehghani H. Time-resolved near infrared light propagation using frequency domain superposition. BIOMEDICAL OPTICS EXPRESS 2018; 9:41-54. [PMID: 29359086 PMCID: PMC5772588 DOI: 10.1364/boe.9.000041] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 11/15/2017] [Accepted: 11/24/2017] [Indexed: 05/02/2023]
Abstract
Time-resolved temporal point spread function (TPSF) measurement of near infrared spectroscopic (NIRS) data allows the estimation of absorption and reduced scattering properties of biological tissues. Such analysis requires an iterative calculation of the theoretical TPSF curve using mathematical and computational models of the domain being imaged which are computationally complex and expensive. In this work, an efficient methodology for representing the TPSF data using a superposition of cosines calculated in frequency domain is presented. The proposed method is outlined and tested on finite element realistic models of the human neck and head. Using an adult head model containing ~140k nodes, the TPSF calculation at each node for one source is accelerated from 3.11 s to 1.29 s within an error limit of ± 5% related to the time domain calculation method.
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Affiliation(s)
- Stanislaw Wojtkiewicz
- School of Computer Science, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Turgut Durduran
- ICFO - Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, Castelldefels (Barcelona), Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain
| | - Hamid Dehghani
- School of Computer Science, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
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10
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Abdalmalak A, Milej D, Diop M, Shokouhi M, Naci L, Owen AM, St. Lawrence K. Can time-resolved NIRS provide the sensitivity to detect brain activity during motor imagery consistently? BIOMEDICAL OPTICS EXPRESS 2017; 8:2162-2172. [PMID: 28736662 PMCID: PMC5516814 DOI: 10.1364/boe.8.002162] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 02/15/2017] [Accepted: 02/27/2017] [Indexed: 05/20/2023]
Abstract
Previous functional magnetic resonance imaging (fMRI) studies have shown that a subgroup of patients diagnosed as being in a vegetative state are aware and able to communicate by performing a motor imagery task in response to commands. Due to the fMRI's cost and accessibility, there is a need for exploring different imaging modalities that can be used at the bedside. A promising technique is functional near infrared spectroscopy (fNIRS) that has been successfully applied to measure brain oxygenation in humans. Due to the limited depth sensitivity of continuous-wave NIRS, time-resolved (TR) detection has been proposed as a way of enhancing the sensitivity to the brain, since late arriving photons have a higher probability of reaching the brain. The goal of this study was to assess the feasibility and sensitivity of TR fNIRS in detecting brain activity during motor imagery. Fifteen healthy subjects were recruited in this study, and the fNIRS results were validated using fMRI. The change in the statistical moments of the distribution of times of flight (number of photons, mean time of flight and variance) were calculated for each channel to determine the presence of brain activity. The results indicate up to an 86% agreement between fMRI and TR-fNIRS and the sensitivity ranging from 64 to 93% with the highest value determined for the mean time of flight. These promising results highlight the potential of TR-fNIRS as a portable brain computer interface for patients with disorder of consciousness.
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Affiliation(s)
- Androu Abdalmalak
- Department of Medical Biophysics, Western University, London, ON, Canada
- Imaging Division, Lawson Health Research Institute, London, ON, Canada
| | - Daniel Milej
- Department of Medical Biophysics, Western University, London, ON, Canada
- Imaging Division, Lawson Health Research Institute, London, ON, Canada
| | - Mamadou Diop
- Department of Medical Biophysics, Western University, London, ON, Canada
- Imaging Division, Lawson Health Research Institute, London, ON, Canada
| | - Mahsa Shokouhi
- Department of Medical Biophysics, Western University, London, ON, Canada
- Imaging Division, Lawson Health Research Institute, London, ON, Canada
| | - Lorina Naci
- Brain and Mind Institute, Western University, London, ON, Canada
| | - Adrian M. Owen
- Brain and Mind Institute, Western University, London, ON, Canada
| | - Keith St. Lawrence
- Department of Medical Biophysics, Western University, London, ON, Canada
- Imaging Division, Lawson Health Research Institute, London, ON, Canada
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11
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Milej D, Abdalmalak A, McLachlan P, Diop M, Liebert A, St. Lawrence K. Subtraction-based approach for enhancing the depth sensitivity of time-resolved NIRS. BIOMEDICAL OPTICS EXPRESS 2016; 7:4514-4526. [PMID: 27895992 PMCID: PMC5119592 DOI: 10.1364/boe.7.004514] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Revised: 09/13/2016] [Accepted: 09/14/2016] [Indexed: 05/18/2023]
Abstract
The aim of this study was to evaluate enhancing of the depth sensitivity of time-resolved near-infrared spectroscopy with a subtraction-based approach. Due to the complexity of light propagation in a heterogeneous media, and to prove the validity of the proposed method in a heterogeneous turbid media we conducted a broad analysis taking into account a number of parameters related to the method as well as various parameters of this media. The results of these experiments confirm that the depth sensitivity of the subtraction-based approach is better than classical approaches using continuous-wave or time-resolved methods. Furthermore, the results showed that the subtraction-based approach has a unique, selective sensitivity to a layer at a specific depth. In vivo application of the proposed method resulted in a greater magnitude of the hemodynamic changes during functional activation than with the standard approach.
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Affiliation(s)
- Daniel Milej
- Department of Medical Biophysics, Western University, London, ON, Canada
- Imaging Division, Lawson Health Research Institute, London, ON, Canada
| | - Androu Abdalmalak
- Department of Medical Biophysics, Western University, London, ON, Canada
- Imaging Division, Lawson Health Research Institute, London, ON, Canada
| | - Peter McLachlan
- Department of Medical Biophysics, Western University, London, ON, Canada
- Imaging Division, Lawson Health Research Institute, London, ON, Canada
| | - Mamadou Diop
- Department of Medical Biophysics, Western University, London, ON, Canada
- Imaging Division, Lawson Health Research Institute, London, ON, Canada
| | - Adam Liebert
- Nalecz Institute of Biocybernetics and Biomedical Engineering, Warsaw, Poland
| | - Keith. St. Lawrence
- Department of Medical Biophysics, Western University, London, ON, Canada
- Imaging Division, Lawson Health Research Institute, London, ON, Canada
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12
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Auger H, Bherer L, Boucher É, Hoge R, Lesage F, Dehaes M. Quantification of extra-cerebral and cerebral hemoglobin concentrations during physical exercise using time-domain near infrared spectroscopy. BIOMEDICAL OPTICS EXPRESS 2016; 7:3826-3842. [PMID: 27867696 PMCID: PMC5102543 DOI: 10.1364/boe.7.003826] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Revised: 08/23/2016] [Accepted: 08/28/2016] [Indexed: 05/10/2023]
Abstract
Fitness is known to have beneficial effects on brain anatomy and function. However, the understanding of mechanisms underlying immediate and long-term neurophysiological changes due to exercise is currently incomplete due to the lack of tools to investigate brain function during physical activity. In this study, we used time-domain near infrared spectroscopy (TD-NIRS) to quantify and discriminate extra-cerebral and cerebral hemoglobin concentrations and oxygen saturation (SO2) in young adults at rest and during incremental intensity exercise. In extra-cerebral tissue, an increase in deoxy-hemoglobin (HbR) and a decrease in SO2 were observed while only cerebral HbR increased at high intensity exercise. Results in extra-cerebral tissue are consistent with thermoregulatory mechanisms to dissipate excess heat through skin blood flow, while cerebral changes are in agreement with cerebral blood flow (CBF) redistribution mechanisms to meet oxygen demand in activated regions during exercise. No significant difference was observed in oxy- (HbO2) and total hemoglobin (HbT). In addition HbO2, HbR and HbT increased with subject's peak power output (equivalent to the maximum oxygen volume consumption; VO2 peak) supporting previous observations of increased total mass of red blood cells in trained individuals. Our results also revealed known gender differences with higher hemoglobin in men. Our approach in quantifying both extra-cerebral and cerebral absolute hemoglobin during exercise may help to better interpret past and future continuous-wave NIRS studies that are prone to extra-cerebral contamination and allow a better understanding of acute cerebral changes due to physical exercise.
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Affiliation(s)
- Héloïse Auger
- Institute of Biomedical Engineering, Université de Montréal, Montréal, QC,
Canada
- Centre Hospitalier Universitaire Sainte-Justine, Montréal, QC,
Canada
| | - Louis Bherer
- Institut Universitaire de Gériatrie de Montréal, Montréal, QC,
Canada
- PERFORM Centre, Concordia University, Montréal, QC,
Canada
| | - Étienne Boucher
- Centre Hospitalier Universitaire Sainte-Justine, Montréal, QC,
Canada
| | - Richard Hoge
- Institut Universitaire de Gériatrie de Montréal, Montréal, QC,
Canada
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC,
Canada
| | - Frédéric Lesage
- Institute of Biomedical Engineering, Université de Montréal, Montréal, QC,
Canada
- Department of Electrical Engineering, École Polytechnique de Montréal, Montréal, QC,
Canada
| | - Mathieu Dehaes
- Institute of Biomedical Engineering, Université de Montréal, Montréal, QC,
Canada
- Centre Hospitalier Universitaire Sainte-Justine, Montréal, QC,
Canada
- Department of Radiology, Radio-Oncology and Nuclear Medicine, Université de Montréal, Montréal, QC,
Canada
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13
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Verdecchia K, Diop M, Lee A, Morrison LB, Lee TY, St. Lawrence K. Assessment of a multi-layered diffuse correlation spectroscopy method for monitoring cerebral blood flow in adults. BIOMEDICAL OPTICS EXPRESS 2016; 7:3659-3674. [PMID: 27699127 PMCID: PMC5030039 DOI: 10.1364/boe.7.003659] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 07/22/2016] [Accepted: 07/26/2016] [Indexed: 05/21/2023]
Abstract
Diffuse correlation spectroscopy (DCS) is a promising technique for brain monitoring as it can provide a continuous signal that is directly related to cerebral blood flow (CBF); however, signal contamination from extracerebral tissue can cause flow underestimations. The goal of this study was to investigate whether a multi-layered (ML) model that accounts for light propagation through the different tissue layers could successfully separate scalp and brain flow when applied to DCS data acquired at multiple source-detector distances. The method was first validated with phantom experiments. Next, experiments were conducted in a pig model of the adult head with a mean extracerebral tissue thickness of 9.8 ± 0.4 mm. Reductions in CBF were measured by ML DCS and computed tomography perfusion for validation; excellent agreement was observed by a mean difference of 1.2 ± 4.6% (CI95%: -31.1 and 28.6) between the two modalities, which was not significantly different.
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Affiliation(s)
- Kyle Verdecchia
- Imaging Program, Lawson Health Research Institute, London, Ontario N6A 4V2, Canada
- Department of Medical Biophysics, University of Western Ontario, London, Ontario N6A 3K7, Canada
| | - Mamadou Diop
- Imaging Program, Lawson Health Research Institute, London, Ontario N6A 4V2, Canada
- Department of Medical Biophysics, University of Western Ontario, London, Ontario N6A 3K7, Canada
| | - Albert Lee
- Department of Medical Biophysics, University of Western Ontario, London, Ontario N6A 3K7, Canada
| | - Laura B. Morrison
- Imaging Program, Lawson Health Research Institute, London, Ontario N6A 4V2, Canada
- Department of Medical Biophysics, University of Western Ontario, London, Ontario N6A 3K7, Canada
| | - Ting-Yim Lee
- Imaging Program, Lawson Health Research Institute, London, Ontario N6A 4V2, Canada
- Department of Medical Biophysics, University of Western Ontario, London, Ontario N6A 3K7, Canada
- Imaging Research Laboratories, Robarts Research Institute, London, Ontario N6G 2V4, Canada
| | - Keith St. Lawrence
- Imaging Program, Lawson Health Research Institute, London, Ontario N6A 4V2, Canada
- Department of Medical Biophysics, University of Western Ontario, London, Ontario N6A 3K7, Canada
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14
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Re R, Contini D, Zucchelli L, Torricelli A, Spinelli L. Effect of a thin superficial layer on the estimate of hemodynamic changes in a two-layer medium by time domain NIRS. BIOMEDICAL OPTICS EXPRESS 2016; 7:264-78. [PMID: 26977338 PMCID: PMC4771447 DOI: 10.1364/boe.7.000264] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Revised: 12/16/2015] [Accepted: 12/16/2015] [Indexed: 05/09/2023]
Abstract
In order to study hemodynamic changes involved in muscular metabolism by means of time domain fNIRS, we need to discriminate in the measured signal contributions coming from different depths. Muscles are, in fact, typically located under other tissues, e.g. skin and fat. In this paper, we study the possibility to exploit a previously proposed method for analyzing time-resolved fNIRS measurements in a two-layer structure with a thin superficial layer. This method is based on the calculation of the time-dependent mean partial pathlengths. We validated it by simulating venous and arterial arm cuff occlusions and then applied it on in vivo measurements.
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Affiliation(s)
- Rebecca Re
- Politecnico di Milano, Dipartimento di Fisica, Piazza Leonardo da Vinci 32, 20133 Milan, Italy
| | - Davide Contini
- Politecnico di Milano, Dipartimento di Fisica, Piazza Leonardo da Vinci 32, 20133 Milan, Italy
| | - Lucia Zucchelli
- Politecnico di Milano, Dipartimento di Fisica, Piazza Leonardo da Vinci 32, 20133 Milan, Italy
| | - Alessandro Torricelli
- Politecnico di Milano, Dipartimento di Fisica, Piazza Leonardo da Vinci 32, 20133 Milan, Italy
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15
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Bakhsheshi MF, Diop M, Morrison LB, St. Lawrence K, Lee TY. Coupling of cerebral blood flow and oxygen consumption during hypothermia in newborn piglets as measured by time-resolved near-infrared spectroscopy: a pilot study. NEUROPHOTONICS 2015; 2:035006. [PMID: 26835481 PMCID: PMC4718069 DOI: 10.1117/1.nph.2.3.035006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Accepted: 08/18/2015] [Indexed: 06/05/2023]
Abstract
Hypothermia (HT) is a potent neuroprotective therapy that is now widely used in following neurological emergencies, such as neonatal asphyxia. An important mechanism of HT-induced neuroprotection is attributed to the associated reduction in the cerebral metabolic rate of oxygen ([Formula: see text]). Since cerebral circulation and metabolism are tightly regulated, reduction in [Formula: see text] typically results in decreased cerebral blood flow (CBF); it is only under oxidative stress, e.g., hypoxia-ischemia, that oxygen extraction fraction (OEF) deviates from its basal value, which can lead to cerebral dysfunction. As such, it is critical to measure these key physiological parameters during therapeutic HT. This report investigates a noninvasive method of measuring the coupling of [Formula: see text] and CBF under HT and different anesthetic combinations of propofol/nitrous-oxide ([Formula: see text]) that may be used in clinical practice. Both CBF and [Formula: see text] decreased with decreasing temperature, but the OEF remained unchanged, which indicates a tight coupling of flow and metabolism under different anesthetics and over the mild HT temperature range (38°C to 33°C).
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Affiliation(s)
- Mohammad Fazel Bakhsheshi
- Lawson Health Research Institute, Imaging Program, 268 Grosvenor Street, London, Ontario N6A 4V2, Canada
- Robarts Research Institute, Imaging Research Laboratories, 1151 Richmond Street North, London, Ontario N6A 5B7, Canada
| | - Mamadou Diop
- Lawson Health Research Institute, Imaging Program, 268 Grosvenor Street, London, Ontario N6A 4V2, Canada
- Western University, Department of Medical Biophysics, London, Ontario N6A 5C1, Canada
| | - Laura B. Morrison
- Lawson Health Research Institute, Imaging Program, 268 Grosvenor Street, London, Ontario N6A 4V2, Canada
| | - Keith St. Lawrence
- Lawson Health Research Institute, Imaging Program, 268 Grosvenor Street, London, Ontario N6A 4V2, Canada
- Robarts Research Institute, Imaging Research Laboratories, 1151 Richmond Street North, London, Ontario N6A 5B7, Canada
- Western University, Department of Medical Biophysics, London, Ontario N6A 5C1, Canada
| | - Ting-Yim Lee
- Lawson Health Research Institute, Imaging Program, 268 Grosvenor Street, London, Ontario N6A 4V2, Canada
- Robarts Research Institute, Imaging Research Laboratories, 1151 Richmond Street North, London, Ontario N6A 5B7, Canada
- Western University, Department of Medical Biophysics, London, Ontario N6A 5C1, Canada
- Western University, Department of Medical Imaging, London, Ontario N6A 5W9, Canada
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16
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Bakhsheshi MF, Lee TY. Non-invasive monitoring of brain temperature by near-infrared spectroscopy. Temperature (Austin) 2014; 2:31-2. [PMID: 27226988 PMCID: PMC4843945 DOI: 10.4161/23328940.2014.967156] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Revised: 09/12/2014] [Accepted: 09/14/2014] [Indexed: 12/02/2022] Open
Abstract
Optical techniques are promising methods for measuring tissue temperature noninvasively due to the transparency of tissue to near infrared-light and the temperature dependent light-absorbing properties of endogenous absorbers, particularly water. Besides being noninvasive, the instruments are compact and portable, permitting bedside monitoring.
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Affiliation(s)
- Mohammad Fazel Bakhsheshi
- Imaging Program; Lawson Health Research Institute; London, Ontario, Canada; Imaging Research Laboratories; Robarts Research Institute; London, Ontario, Canada
| | - Ting-Yim Lee
- Imaging Program; Lawson Health Research Institute; London, Ontario, Canada; Imaging Research Laboratories; Robarts Research Institute; London, Ontario, Canada; Department of Medical Biophysics; Western University; London, Ontario, Canada
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