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Rodrigues A, Shingai K, Gómez CA, Rassam P, Rozenberg D, Goligher E, Brochard L, Roblyer D, Reid WD. Continuous measurements of respiratory muscle blood flow and oxygen consumption using noninvasive frequency-domain near-infrared spectroscopy and diffuse correlation spectroscopy. J Appl Physiol (1985) 2024; 137:382-393. [PMID: 38867669 DOI: 10.1152/japplphysiol.00871.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 06/10/2024] [Accepted: 06/11/2024] [Indexed: 06/14/2024] Open
Abstract
Prior studies of muscle blood flow and muscle-specific oxygen consumption have required invasive injection of dye and magnetic resonance imaging, respectively. Such measures have limited utility for continuous monitoring of the respiratory muscles. Frequency-domain near-infrared spectroscopy and diffuse correlation spectroscopy (FD-NIRS & DCS) can provide continuous surrogate measures of blood flow index (BFi) and metabolic rate of oxygen consumption (MRO2). This study aimed to validate sternocleidomastoid FD-NIRS & DCS outcomes against electromyography (EMG) and mouth pressure (Pm) during incremental inspiratory threshold loading (ITL). Six female and six male healthy adults (means ± SD; 30 ± 7 yr, maximum inspiratory pressure 118 ± 61 cmH2O) performed incremental ITL starting at low loads (8 ± 2 cmH2O) followed by 50-g increments every 2 min until task failure. FD-NIRS & DCS continuously measured sternocleidomastoid oxygenated and deoxygenated hemoglobin + myoglobin (oxy/deoxy[Hb + Mb]), tissue saturation of oxygen (StO2), BFi, and MRO2. Ventilatory parameters including inspiratory Pm were also evaluated. Pm increased during incremental ITL (P < 0.05), reaching -47[-74 to -34] cmH2O (median [IQR: 25%-75%]) at task failure. Ventilatory parameters were constant throughout ITL (all P > 0.05). Sternocleidomastoid BFi and MRO2 increased from the start of the ITL (both P < 0.05). Deoxy[Hb + Mb] increased close to task failure, concomitantly with a constant increase in MRO2, and decreased StO2. Sternocleidomastoid deoxy[Hb + Mb], BFi, StO2, and MRO2 obtained during ITL via FD-NIRS & DCS correlated with sternocleidomastoid EMG (all P < 0.05). In healthy adults, FD-NIRS & DCS can provide continuous surrogate measures of respiratory BFi and MRO2. Increasing sternocleidomastoid oxygen consumption near task failure was associated with increased oxygen extraction and reduced tissue saturation.NEW & NOTEWORTHY This study introduces a novel approach, frequency-domain near-infrared spectroscopy and diffuse correlation spectroscopy (FD-NIRS & DCS), for noninvasive continuous monitoring of respiratory muscle blood flow and metabolic rate of oxygen consumption. Unlike prior methods involving invasive dye injection and magnetic resonance imaging, FD-NIRS & DCS offers the advantage of continuous measurement without the need for invasive procedures. It holds promise for advancing muscle physiology understanding and opens avenues for real-time monitoring of respiratory muscles.
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Affiliation(s)
- Antenor Rodrigues
- Department of Critical Care, Keenan Research Centre, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Unity Health Toronto, Toronto, Ontario, Canada
- Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Kazuya Shingai
- Department of Physical Therapy, University of Toronto, Toronto, Ontario, Canada
- Department of Physical Therapy Science, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Carlos A Gómez
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts, United States
| | - Peter Rassam
- Department of Physical Therapy, University of Toronto, Toronto, Ontario, Canada
| | - Dmitry Rozenberg
- Ajmera Transplant Program, Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada
- Division of Respirology, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Ewan Goligher
- Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Laurent Brochard
- Department of Critical Care, Keenan Research Centre, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Unity Health Toronto, Toronto, Ontario, Canada
- Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Darren Roblyer
- Department of Physical Therapy Science, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - W Darlene Reid
- Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, Ontario, Canada
- Department of Physical Therapy, University of Toronto, Toronto, Ontario, Canada
- KITE, Toronto Rehabilitation Institute, University Health Network, Toronto, Ontario, Canada
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2
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Gómez CA, Brochard L, Goligher EC, Rozenberg D, Reid WD, Roblyer D. Combined frequency domain near-infrared spectroscopy and diffuse correlation spectroscopy system for comprehensive metabolic monitoring of inspiratory muscles during loading. JOURNAL OF BIOMEDICAL OPTICS 2024; 29:035002. [PMID: 38532926 PMCID: PMC10965138 DOI: 10.1117/1.jbo.29.3.035002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 03/08/2024] [Accepted: 03/12/2024] [Indexed: 03/28/2024]
Abstract
Significance Mechanical ventilation (MV) is a cornerstone technology in the intensive care unit as it assists with the delivery of oxygen in critically ill patients. The process of weaning patients from MV can be long and arduous and can lead to serious complications for many patients. Despite the known importance of inspiratory muscle function in the success of weaning, current clinical standards do not include direct monitoring of these muscles. Aim The goal of this project was to develop and validate a combined frequency domain near-infrared spectroscopy (FD-NIRS) and diffuse correlation spectroscopy (DCS) system for the noninvasive characterization of inspiratory muscle response to a load. Approach The system was fabricated by combining a custom digital FD-NIRS and DCS system. It was validated via liquid phantom titrations and a healthy volunteer study. The sternocleidomastoid (SCM), an accessory muscle of inspiration, was monitored during a short loading period in fourteen young, healthy volunteers. Volunteers performed two different respiratory exercises, a moderate load and a high load, which consisted of a one-minute baseline, a one-minute load, and a six-minute recovery period. Results The system has low crosstalk between absorption, reduced scattering, and flow when tested in a set of liquid titrations. Faster dynamics were observed for changes in blood flow index (BF i ), and metabolic rate of oxygen (MRO 2 ) compared with hemoglobin + myoglobin (Hb+Mb) based parameters after the onset of loads in males. Additionally, larger percent changes in BF i , and MRO 2 were observed compared with Hb+Mb parameters in both males and females. There were also sex differences in baseline values of oxygenated Hb+Mb, total Hb+Mb, and tissue saturation. Conclusions The dynamic characteristics of Hb+Mb concentration and blood flow were distinct during loading of the SCM, suggesting that the combination of FD-NIRS and DCS may provide a more complete picture of inspiratory muscle dynamics.
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Affiliation(s)
- Carlos A. Gómez
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - Laurent Brochard
- St. Michael’s Hospital, Unity Health Toronto, Li Ka Shing Knowledge Institute, Keenan Research Centre, Toronto, Ontario, Canada
- St. Michael’s Hospital, Department of Critical Care, Toronto, Ontario, Canada
- University of Toronto, Interdepartmental Division of Critical Care Medicine, Toronto, Ontario, Canada
| | - Ewan C. Goligher
- University of Toronto, Interdepartmental Division of Critical Care Medicine, Toronto, Ontario, Canada
- University Health Network, Toronto General Hospital Research Institute, Toronto, Ontario, Canada
- University of Toronto, Department of Physiology, Toronto, Ontario, Canada
| | - Dmitry Rozenberg
- University Health Network, Toronto General Hospital Research Institute, Ajmera Transplant Center, Toronto, Ontario, Canada
- University of Toronto, Division of Respirology, Temerty Faculty of Medicine, Toronto, Ontario, Canada
| | - W. Darlene Reid
- University of Toronto, Department of Physical Therapy, Toronto, Ontario, Canada
- University of Toronto, Interdepartmental Division of Critical Care Medicine, Toronto, Ontario, Canada
- University Health Network, KITE – Toronto Rehabilitation Institute, Toronto, Ontario, Canada
| | - Darren Roblyer
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
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Durkee MS, Ai J, Casella G, Cao T, Chang A, Halper-Stromberg A, Jabri B, Clark MR, Giger ML. Pseudo-spectral angle mapping for automated pixel-level analysis of highly multiplexed tissue image data. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.09.574920. [PMID: 38260318 PMCID: PMC10802447 DOI: 10.1101/2024.01.09.574920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
The rapid development of highly multiplexed microscopy systems has enabled the study of cells embedded within their native tissue, which is providing exciting insights into the spatial features of human disease [1]. However, computational methods for analyzing these high-content images are still emerging, and there is a need for more robust and generalizable tools for evaluating the cellular constituents and underlying stroma captured by high-plex imaging [2]. To address this need, we have adapted spectral angle mapping - an algorithm used widely in hyperspectral image analysis - to compress the channel dimension of high-plex immunofluorescence images. As many high-plex immunofluorescence imaging experiments probe unique sets of protein markers, existing cell and pixel classification models do not typically generalize well. Pseudospectral angle mapping (pSAM) uses reference pseudospectra - or pixel vectors - to assign each pixel in an image a similarity score to several cell class reference vectors, which are defined by each unique staining panel. Here, we demonstrate that the class maps provided by pSAM can directly provide insight into the prevalence of each class defined by reference pseudospectra. In a dataset of high-plex images of colon biopsies from patients with gut autoimmune conditions, sixteen pSAM class representation maps were combined with instance segmentation of cells to provide cell class predictions. Finally, pSAM detected a diverse set of structure and immune cells when applied to a novel dataset of kidney biopsies imaged with a 43-marker panel. In summary, pSAM provides a powerful and readily generalizable method for evaluating high-plex immunofluorescence image data.
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Affiliation(s)
| | - Junting Ai
- Department of Medicine, Section on Rheumatology, The University of Chicago, Chicago, IL, USA, 60637
| | - Gabriel Casella
- Department of Radiology, The University of Chicago, Chicago, IL, USA, 60637
- Department of Medicine, Section on Rheumatology, The University of Chicago, Chicago, IL, USA, 60637
| | - Thao Cao
- Pritzker School of Molecular Engineering, The University of Chicago, Chicago, IL, USA, 60637
| | - Anthony Chang
- Department of Pathology, The University of Chicago, Chicago, IL, USA, 60637
| | - Ariel Halper-Stromberg
- Department of Medicine, Section on Gastroenterology, Hepatology & Nutrition, The University of Chicago, Chicago, IL, USA, 60637
| | - Bana Jabri
- Department of Medicine, Section on Gastroenterology, Hepatology & Nutrition, The University of Chicago, Chicago, IL, USA, 60637
| | - Marcus R. Clark
- Department of Medicine, Section on Rheumatology, The University of Chicago, Chicago, IL, USA, 60637
| | - Maryellen L. Giger
- Department of Radiology, The University of Chicago, Chicago, IL, USA, 60637
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4
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Gómez CA, Brochard L, Goligher EC, Rozenberg D, Reid WD, Roblyer D. A combined frequency domain near infrared spectroscopy and diffuse correlation spectroscopy system for comprehensive metabolic monitoring of inspiratory muscles during loading. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.30.569133. [PMID: 38076980 PMCID: PMC10705398 DOI: 10.1101/2023.11.30.569133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/23/2023]
Abstract
Significance Mechanical ventilation (MV) is a cornerstone technology in the intensive care unit as it assists with the delivery of oxygen in critical ill patients. The process of weaning patients from MV can be long, and arduous and can lead to serious complications for many patients. Despite the known importance of inspiratory muscle function in the success of weaning, current clinical standards do not include direct monitoring of these muscles. Aim The goal of this project was to develop and validate a combined frequency domain near infrared spectroscopy (FD-NIRS) and diffuse correlation spectroscopy (DCS) system for the noninvasive characterization of inspiratory muscle response to a load. Approach The system was fabricated by combining a custom digital FD-NIRS and DCS system. It was validated via liquid phantom titrations and a healthy volunteer study. The sternocleidomastoid (SCM), an accessory muscle of inspiration, was monitored during a short loading period in fourteen young healthy volunteer. Volunteers performed two different respiratory exercises, a moderate and high load, which consisted of a one-minute baseline, a one-minute load, and a six-minute recovery period. Results The system has low crosstalk between absorption, reduced scattering, and flow when tested in a set of liquid titrations. Faster dynamics were observed for changes in blood flow index (BFi), and metabolic rate of oxygen (MRO2) compared to hemoglobin + myoglobin (Hb+Mb) based parameters after the onset of loads in males. Additionally, larger percent changes in BFi, and MRO2 were observed compared to Hb+Mb parameters in both males and females. There were also sex differences in baseline values of oxygenated Hb+Mb, total Hb+Mb, and tissue saturation. Conclusion The dynamic characteristics of Hb+Mb concentration and blood flow were distinct during loading of the SCM, suggesting that the combination of FD-NIRS and DCS may provide a more complete picture of inspiratory muscle dynamics.
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Affiliation(s)
- Carlos A Gómez
- Department of Biomedical Engineering, Boston University, Boston, MA 02125, USA
| | - Laurent Brochard
- Keenan Research Centre, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Unity Health Toronto, Toronto, ON, Canada
- Department of Critical Care, St. Michael's Hospital, Toronto, ON, Canada
- Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, ON, Canada
| | - Ewan C Goligher
- Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, ON, Canada
- Toronto General Hospital Research Institute, University Health Network, Toronto, ON, Canada
- Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Dmitry Rozenberg
- Division of Respirology, Temerty Faculty of Medicine, University of Toronto, ON, Canada
- Department of Physical Therapy, University of Toronto, Toronto, ON, Canada
| | - W Darlene Reid
- Department of Physical Therapy, University of Toronto, Toronto, ON, Canada
- Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, ON, Canada
- KITE - Toronto Rehabilitation Institute, University Health Network, Toronto, ON, Canada
| | - Darren Roblyer
- Department of Biomedical Engineering, Boston University, Boston, MA 02125, USA
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Djinbachian R, Khellaf A, Noyon B, Soucy G, Nguyen BN, von Renteln D. Accuracy of measuring colorectal polyp size in pathology: a prospective study. Gut 2023; 72:2015-2018. [PMID: 37507216 DOI: 10.1136/gutjnl-2023-330241] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Accepted: 07/11/2023] [Indexed: 07/30/2023]
Affiliation(s)
- Roupen Djinbachian
- Gastroenterology, Montreal University Hospital Center (CHUM), Montreal, Quebec, Canada
- Gastroenterology, Montreal University Hospital Research Center (CRCHUM), Montreal, Quebec, Canada
| | - Abdelhakim Khellaf
- Pathology, Montreal University Hospital Center (CHUM), Montreal, Quebec, Canada
| | - Brandon Noyon
- Gastroenterology, Montreal University Hospital Research Center (CRCHUM), Montreal, Quebec, Canada
| | - Geneviève Soucy
- Pathology, Montreal University Hospital Center (CHUM), Montreal, Quebec, Canada
| | - Bich N Nguyen
- Pathology, Montreal University Hospital Center (CHUM), Montreal, Quebec, Canada
| | - Daniel von Renteln
- Gastroenterology, Montreal University Hospital Center (CHUM), Montreal, Quebec, Canada
- Gastroenterology, Montreal University Hospital Research Center (CRCHUM), Montreal, Quebec, Canada
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6
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Zhou X, Xia Y, Uchitel J, Collins-Jones L, Yang S, Loureiro R, Cooper RJ, Zhao H. Review of recent advances in frequency-domain near-infrared spectroscopy technologies [Invited]. BIOMEDICAL OPTICS EXPRESS 2023; 14:3234-3258. [PMID: 37497520 PMCID: PMC10368025 DOI: 10.1364/boe.484044] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 04/29/2023] [Accepted: 05/25/2023] [Indexed: 07/28/2023]
Abstract
Over the past several decades, near-infrared spectroscopy (NIRS) has become a popular research and clinical tool for non-invasively measuring the oxygenation of biological tissues, with particular emphasis on applications to the human brain. In most cases, NIRS studies are performed using continuous-wave NIRS (CW-NIRS), which can only provide information on relative changes in chromophore concentrations, such as oxygenated and deoxygenated hemoglobin, as well as estimates of tissue oxygen saturation. Another type of NIRS known as frequency-domain NIRS (FD-NIRS) has significant advantages: it can directly measure optical pathlength and thus quantify the scattering and absorption coefficients of sampled tissues and provide direct measurements of absolute chromophore concentrations. This review describes the current status of FD-NIRS technologies, their performance, their advantages, and their limitations as compared to other NIRS methods. Significant landmarks of technological progress include the development of both benchtop and portable/wearable FD-NIRS technologies, sensitive front-end photonic components, and high-frequency phase measurements. Clinical applications of FD-NIRS technologies are discussed to provide context on current applications and needed areas of improvement. The review concludes by providing a roadmap toward the next generation of fully wearable, low-cost FD-NIRS systems.
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Affiliation(s)
- Xinkai Zhou
- HUB of Intelligent Neuro-engineering (HUBIN), Aspire CREATe, IOMS, Division of Surgery and Interventional Science, University College London (UCL), London, HA7 4LP, UK
| | - Yunjia Xia
- HUB of Intelligent Neuro-engineering (HUBIN), Aspire CREATe, IOMS, Division of Surgery and Interventional Science, University College London (UCL), London, HA7 4LP, UK
- DOT-HUB, Department of Medical Physics & Biomedical Engineering, UCL, London, WC1E 6BT, UK
| | - Julie Uchitel
- Department of Paediatrics, University of Cambridge, Cambridge, CB2 0QQ, UK
| | - Liam Collins-Jones
- DOT-HUB, Department of Medical Physics & Biomedical Engineering, UCL, London, WC1E 6BT, UK
| | - Shufan Yang
- HUB of Intelligent Neuro-engineering (HUBIN), Aspire CREATe, IOMS, Division of Surgery and Interventional Science, University College London (UCL), London, HA7 4LP, UK
- School of Computing, Engineering & Build Environment, Edinburgh Napier University, Edinburgh, UK
| | - Rui Loureiro
- Aspire CREATe, Department of Orthopaedics & Musculoskeletal Science, UCL, London, HA7 4LP, UK
| | - Robert J. Cooper
- DOT-HUB, Department of Medical Physics & Biomedical Engineering, UCL, London, WC1E 6BT, UK
| | - Hubin Zhao
- HUB of Intelligent Neuro-engineering (HUBIN), Aspire CREATe, IOMS, Division of Surgery and Interventional Science, University College London (UCL), London, HA7 4LP, UK
- DOT-HUB, Department of Medical Physics & Biomedical Engineering, UCL, London, WC1E 6BT, UK
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7
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von Renteln D, Djinbachian R, Zarandi-Nowroozi M, Taghiakbari M. Measuring size of smaller colorectal polyps using a virtual scale function during endoscopies. Gut 2023; 72:417-420. [PMID: 36411028 DOI: 10.1136/gutjnl-2022-328654] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Accepted: 11/12/2022] [Indexed: 11/22/2022]
Affiliation(s)
- Daniel von Renteln
- University of Montreal, Montreal, Quebec, Canada .,Department of Medicine, Division of Gastroenterology, CHUM, Montreal, Quebec, Canada
| | - Roupen Djinbachian
- Department of Medicine, Division of Gastroenterology, CHUM, Montreal, Quebec, Canada
| | | | - Mahsa Taghiakbari
- University of Montreal, Montreal, Quebec, Canada.,CRCHUM, Montreal, Quebec, Canada
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8
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Stillwell RA, Kitsmiller VJ, Wei AY, Chong A, Senn L, O’Sullivan TD. A scalable, multi-wavelength, broad bandwidth frequency-domain near-infrared spectroscopy platform for real-time quantitative tissue optical imaging. BIOMEDICAL OPTICS EXPRESS 2021; 12:7261-7279. [PMID: 34858713 PMCID: PMC8606133 DOI: 10.1364/boe.435913] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 10/07/2021] [Accepted: 10/21/2021] [Indexed: 05/25/2023]
Abstract
Frequency-domain near-infrared spectroscopy (FD-NIRS) provides quantitative noninvasive measurements of tissue optical absorption and scattering, as well as a safe and accurate method for characterizing tissue composition and metabolism. However, the poor scalability and high complexity of most FD-NIRS systems assembled to date have contributed to its limited clinical impact. To address these shortcomings, we present a scalable, digital-based FD-NIRS platform capable of measuring optical properties and tissue chromophore concentrations in real-time. The system provides single-channel FD-NIRS amplitude/phase, optical property, and chromophore data at a maximum display rate of 36.6 kHz, 17.9 kHz, and 10.2 kHz, respectively, and can be scaled to multiple channels as well as integrated into a handheld format. The entire system is enabled by several innovations including an ultra-high-speed k-nearest neighbor lookup table method (maximum of 250,000 inversions/s for a large 2500x700 table of absorption and reduced scattering coefficients), embedded FPGA and CPU high-speed co-processing, and high-speed data transfer (due to on-board processing). We show that our 6-wavelength, broad modulation bandwidth (1-400 MHz) system can be used to perform 2D high-density spatial mapping of optical properties and high speed quantification of hemodynamics.
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Affiliation(s)
- Roy A. Stillwell
- Department of Electrical Engineering, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - Vincent J. Kitsmiller
- Department of Electrical Engineering, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - Alicia Y. Wei
- Department of Electrical Engineering, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - Alyssa Chong
- St. Mary’s College, Notre Dame, Indiana 46556, USA
| | - Lyla Senn
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - Thomas D. O’Sullivan
- Department of Electrical Engineering, University of Notre Dame, Notre Dame, Indiana 46556, USA
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9
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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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Mohammad PPS, Isarangura S, Eddins A, Parthasarathy AB. Comparison of functional activation responses from the auditory cortex derived using multi-distance frequency domain and continuous wave near-infrared spectroscopy. NEUROPHOTONICS 2021; 8:045004. [PMID: 34926716 PMCID: PMC8673635 DOI: 10.1117/1.nph.8.4.045004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 11/29/2021] [Indexed: 05/08/2023]
Abstract
Significance: Quantitative measurements of cerebral hemodynamic changes due to functional activation are widely accomplished with commercial continuous wave (CW-NIRS) instruments despite the availability of the more rigorous multi-distance frequency domain (FD-NIRS) approach. A direct comparison of the two approaches to functional near-infrared spectroscopy can help in the interpretation of optical data and guide implementations of diffuse optical instruments for measuring functional activation. Aim: We explore the differences between CW-NIRS and multi-distance FD-NIRS by comparing measurements of functional activation in the human auditory cortex. Approach: Functional activation of the human auditory cortex was measured using a commercial frequency domain near-infrared spectroscopy instrument for 70 dB sound pressure level broadband noise and pure tone (1000 Hz) stimuli. Changes in tissue oxygenation were calculated using the modified Beer-Lambert law (CW-NIRS approach) and the photon diffusion equation (FD-NIRS approach). Results: Changes in oxygenated hemoglobin measured with the multi-distance FD-NIRS approach were about twice as large as those measured with the CW-NIRS approach. A finite-element simulation of the functional activation problem was performed to demonstrate that tissue oxygenation changes measured with the CW-NIRS approach is more accurate than that with multi-distance FD-NIRS. Conclusions: Multi-distance FD-NIRS approaches tend to overestimate functional activation effects, in part due to partial volume effects.
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Affiliation(s)
| | - Sittiprapa Isarangura
- University of South Florida, Department of Communication Sciences and Disorders, Tampa, Florida, United States
| | - Ann Eddins
- University of South Florida, Department of Communication Sciences and Disorders, Tampa, Florida, United States
| | - Ashwin B. Parthasarathy
- University of South Florida, Department of Electrical Engineering, Tampa, Florida, United States
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11
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Istfan R, Gómez CA, Applegate M, Rozenberg D, Reid WD, Roblyer D. Hemodynamics of the sternocleidomastoid measured with frequency domain near-infrared spectroscopy towards non-invasive monitoring during mechanical ventilation. BIOMEDICAL OPTICS EXPRESS 2021; 12:4147-4162. [PMID: 34457405 PMCID: PMC8367268 DOI: 10.1364/boe.430423] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 06/05/2021] [Accepted: 06/08/2021] [Indexed: 06/13/2023]
Abstract
Mechanical ventilation (MV) is used to assist spontaneous breathing in critically ill patients in the intensive care unit (ICU). MV is a cornerstone of critical care medicine but it is now known that inspiratory muscle dysfunction due to injury, disuse, and/or atrophy during MV plays a major role in outcomes for these patients. For example, prolonged MV is strongly correlated with dysfunction of the sternocleidomastoid (SCM), an accessory inspiratory muscle that has been linked to weaning failure from MV. Hemodynamic monitoring of the SCM may provide an important non-invasive and real-time means to monitor MV. In this work, we first conducted multi-layer Monte Carlo simulations to confirm the ability of near infrared light to detect changes in the oxygenation of the SCM over wide ranges of skin tones and adipose layer thicknesses. We then optimized a custom digital frequency domain near-infrared spectroscopy (FD-NIRS) system for continuous 10 Hz measurements of the SCM at 730 nm and 850 nm. A healthy volunteer study was conducted (N=10); subjects performed sets of isometric neck flexions of the SCM. Substantial changes in oxyhemoglobin + oxymyoglobin (oxy[Hb + Mb]), deoxyhemoglobin + deoxymyoglobin (deoxy[Hb + Mb]), and total hemoglobin + myoglobin (total[Hb + Mb]) were observed during sustained and intermittent isometric flexions. There were notable sex differences observed in the magnitude of hemodynamic changes (∼2x larger changes in males for oxy[Hb + Mb] and deoxy[Hb + Mb]). The magnitude of hemodynamic changes when taking into account µs' changes during flexions was ∼ 2-2.5x larger as compared to assuming constant scattering (CS), which is a common assumption used for continuous wave (CW) NIRS methods. This study suggests that FD-NIRS provides improved accuracy for hemodynamic monitoring of the SCM compared to CW-NIRS, and that FD-NIRS may provide value for SCM monitoring during MV.
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Affiliation(s)
- Raeef Istfan
- Department of Biomedical Engineering, Boston University, Boston, MA 02125, USA
| | - Carlos A. Gómez
- Department of Biomedical Engineering, Boston University, Boston, MA 02125, USA
| | - Matthew Applegate
- Department of Biomedical Engineering, Boston University, Boston, MA 02125, USA
| | - Dmitry Rozenberg
- Department of Medicine, Respirology and Lung Transplantation, University Health Network, University of Toronto, Toronto, ON, Canada
| | - W. Darlene Reid
- Department of Physical Therapy, University of Toronto, Toronto ON, Canada
- Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, ON, Canada
- KITE - Toronto Rehabilitation Institute, University Health Network, Toronto, ON, Canada
| | - Darren Roblyer
- Department of Biomedical Engineering, Boston University, Boston, MA 02125, USA
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Spink SS, Teng F, Pera V, Peterson HM, Cormier T, Sauer-Budge A, Chargin D, Brookfield S, Eggebrecht AT, Ko N, Roblyer D. High optode-density wearable diffuse optical probe for monitoring paced breathing hemodynamics in breast tissue. JOURNAL OF BIOMEDICAL OPTICS 2021; 26:JBO-200339SSR. [PMID: 34080400 PMCID: PMC8170390 DOI: 10.1117/1.jbo.26.6.062708] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 05/16/2021] [Indexed: 06/12/2023]
Abstract
SIGNIFICANCE Diffuse optical imaging (DOI) provides in vivo quantification of tissue chromophores such as oxy- and deoxyhemoglobin (HbO2 and HHb, respectively). These parameters have been shown to be useful for predicting neoadjuvant treatment response in breast cancer patients. However, most DOI devices designed for the breast are nonportable, making frequent longitudinal monitoring during treatment a challenge. Furthermore, hemodynamics related to the respiratory cycle are currently unexplored in the breast and may have prognostic value. AIM To design, fabricate, and validate a high optode-density wearable continuous wave diffuse optical probe for the monitoring of breathing hemodynamics in breast tissue. APPROACH The probe has a rigid-flex design with 16 dual-wavelength sources and 16 detectors. Performance was characterized on tissue-simulating phantoms, and validation was performed through flow phantom and cuff occlusion measurements. The breasts of N = 4 healthy volunteers were measured while performing a breathing protocol. RESULTS The probe has 512 unique source-detector (S-D) pairs that span S-D separations of 10 to 54 mm. It exhibited good performance characteristics: μa drift of 0.34%/h, μa precision of 0.063%, and mean SNR ≥ 24 dB up to 41 mm S-D separation. Absorption contrast was detected in flow phantoms at depths exceeding 28 mm. A cuff occlusion measurement confirmed the ability of the probe to track expected hemodynamics in vivo. Breast measurements on healthy volunteers during paced breathing revealed median signal-to-motion artifact ratios ranging from 8.1 to 8.7 dB. Median ΔHbO2 and ΔHHb amplitudes ranged from 0.39 to 0.67 μM and 0.08 to 0.12 μM, respectively. Median oxygen saturations at the respiratory rate ranged from 82% to 87%. CONCLUSIONS A wearable diffuse optical probe has been designed and fabricated for the measurement of breast tissue hemodynamics. This device is capable of quantifying breathing-related hemodynamics in healthy breast tissue.
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Affiliation(s)
- Samuel S. Spink
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - Fei Teng
- Boston University, Department of Electrical and Computer Engineering, Boston, Massachusetts, United States
| | - Vivian Pera
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - Hannah M. Peterson
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - Tim Cormier
- Boston University, Fraunhofer Center for Manufacturing Innovation, Boston, Massachusetts, United States
| | - Alexis Sauer-Budge
- Boston University, Fraunhofer Center for Manufacturing Innovation, Boston, Massachusetts, United States
| | - David Chargin
- Boston University, Fraunhofer Center for Manufacturing Innovation, Boston, Massachusetts, United States
| | - Sam Brookfield
- Boston University, Fraunhofer Center for Manufacturing Innovation, Boston, Massachusetts, United States
| | - Adam T. Eggebrecht
- Washington University, Department of Radiology, St. Louis, Missouri, United States
| | - Naomi Ko
- Boston Medical Center, Section of Hematology and Oncology, Women’s Health Unit, Boston, Massachusetts, United States
| | - Darren Roblyer
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
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Applegate MB, Amelard R, Gomez CA, Roblyer D. Real-Time Handheld Probe Tracking and Image Formation Using Digital Frequency-Domain Diffuse Optical Spectroscopy. IEEE Trans Biomed Eng 2021; 68:3399-3409. [PMID: 33835913 DOI: 10.1109/tbme.2021.3072036] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
OBJECTIVE Frequency-domain diffuse optical spectroscopic imaging (FD-DOS) is a non-invasive method for measuring absolute concentrations of tissue chromophores such as oxy- and deoxy-hemoglobin in vivo. The utility of FD-DOS for clinical applications such as monitoring chemotherapy response in breast cancer has previously been demonstrated, but challenges for further clinical translation, such as slow acquisition speed and lack of user feedback, remain. Here, we propose a new high speed FD-DOS instrument that allows users to freely acquire measurements over the tissue surface, and is capable of rapidly imaging large volumes of tissue. METHODS We utilize 3D monocular probe tracking combined with custom digital FD-DOS hardware and a high-speed data processing pipeline for the instrument. Results are displayed during scanning over the surface of the sample using a probabilistic Monte Carlo light propagation model. RESULTS We show this instrument can measure absorption and scattering coefficients with an error of 7% and 1% respectively, with 0.7 mm positional accuracy. We demonstrate the equivalence of our visualization methodology with a standard interpolation approach, and demonstrate two proof-of-concept in vivo results showing superficial vasculature in the human forearm and surface contrast in a healthy human breast. CONCLUSION Our new FD-DOS system is able to compute chromophore concentrations in real-time (1.5 Hz) in vivo. SIGNIFICANCE This method has the potential to improve the quality of FD-DOS image scans while reducing measurement times for a variety of clinical applications.
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