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Wang Q, Pan M, Kreiss L, Samaei S, Carp SA, Johansson JD, Zhang Y, Wu M, Horstmeyer R, Diop M, Li DDU. A comprehensive overview of diffuse correlation spectroscopy: Theoretical framework, recent advances in hardware, analysis, and applications. Neuroimage 2024; 298:120793. [PMID: 39153520 DOI: 10.1016/j.neuroimage.2024.120793] [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: 05/19/2024] [Revised: 07/23/2024] [Accepted: 08/14/2024] [Indexed: 08/19/2024] Open
Abstract
Diffuse correlation spectroscopy (DCS) is a powerful tool for assessing microvascular hemodynamic in deep tissues. Recent advances in sensors, lasers, and deep learning have further boosted the development of new DCS methods. However, newcomers might feel overwhelmed, not only by the already-complex DCS theoretical framework but also by the broad range of component options and system architectures. To facilitate new entry to this exciting field, we present a comprehensive review of DCS hardware architectures (continuous-wave, frequency-domain, and time-domain) and summarize corresponding theoretical models. Further, we discuss new applications of highly integrated silicon single-photon avalanche diode (SPAD) sensors in DCS, compare SPADs with existing sensors, and review other components (lasers, sensors, and correlators), as well as data analysis tools, including deep learning. Potential applications in medical diagnosis are discussed and an outlook for the future directions is provided, to offer effective guidance to embark on DCS research.
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Affiliation(s)
- Quan Wang
- Department of Biomedical Engineering, Faculty of Engineering, University of Strathclyde, Glasgow, United Kingdom
| | - Mingliang Pan
- Department of Biomedical Engineering, Faculty of Engineering, University of Strathclyde, Glasgow, United Kingdom
| | - Lucas Kreiss
- Department of Biomedical Engineering, Duke University, Durham, NC, United States
| | - Saeed Samaei
- Department of Medical and Biophysics, Schulich School of Medical & Dentistry, Western University, London, Ontario, Canada; Lawson Health Research Institute, Imaging Program, London, Ontario, Canada
| | - Stefan A Carp
- Massachusetts General Hospital, Optics at Athinoula A. Martinos Center for Biomedical Imaging, Harvard Medical School, Charlestown, MA, United States
| | | | - Yuanzhe Zhang
- Department of Biomedical Engineering, Faculty of Engineering, University of Strathclyde, Glasgow, United Kingdom
| | - Melissa Wu
- Department of Biomedical Engineering, Duke University, Durham, NC, United States
| | - Roarke Horstmeyer
- Department of Biomedical Engineering, Duke University, Durham, NC, United States
| | - Mamadou Diop
- Department of Medical and Biophysics, Schulich School of Medical & Dentistry, Western University, London, Ontario, Canada; Lawson Health Research Institute, Imaging Program, London, Ontario, Canada
| | - David Day-Uei Li
- Department of Biomedical Engineering, Faculty of Engineering, University of Strathclyde, Glasgow, United Kingdom.
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Lewis AV, Fang Q. Revisiting equivalent optical properties for cerebrospinal fluid to improve diffusion-based modeling accuracy in the brain. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.20.608859. [PMID: 39229084 PMCID: PMC11370459 DOI: 10.1101/2024.08.20.608859] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 09/05/2024]
Abstract
Significance The diffusion approximation (DA) is used in functional near-infrared spectroscopy (fNIRS) studies despite its known limitations due to the presence of cerebrospinal fluid (CSF). Nearly all of these studies rely on a set of empirical CSF optical properties, recommended by a previous simulation study, that were not selected for the purpose of minimizing DA modeling errors. Aim We aim to directly quantify the accuracy of DA solutions in brain models by comparing those with the gold-standard solutions produced by the mesh-based Monte Carlo (MMC), based on which we derive updated recommendations. Approach For both a 5-layer head and Colin27 atlas models, we obtain DA solutions by independently sweeping the CSF absorption (μ a ) and reduced scattering (μ s ' ) coefficients. Using an MMC solution with literature CSF optical properties as reference, we compute the errors for surface fluence, total brain sensitivity and brain energy-deposition, and identify the optimized settings where the such error is minimized. Results Our results suggest that previously recommended CSF properties can cause significant errors (8.7% to 52%) in multiple tested metrics. By simultaneously sweepingμ a andμ s ' , we can identify infinite numbers of solutions that can exactly match DA with MMC solutions for any single tested metric. Furthermore, it is also possible to simultaneously minimize multiple metrics at multiple source/detector separations, leading to our new recommendation of settingμ s ' = 0.15 mm-1 while maintaining physiologicalμ a for CSF in DA simulations. Conclusion Our new recommendation of CSF equivalent optical properties can greatly reduce the model mismatches between DA and MMC solutions at multiple metrics without sacrificing computational speed. We also show that it is possible to eliminate such a mismatch for a single or a pair of metrics of interest.
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Affiliation(s)
- Aiden Vincent Lewis
- Northeastern University, Department of Bioengineering, 360 Huntington Avenue, Boston, USA, 02115
| | - Qianqian Fang
- Northeastern University, Department of Bioengineering, 360 Huntington Avenue, Boston, USA, 02115
- Northeastern University, Department of EECS, 360 Huntington Avenue, Boston, USA, 02115
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Williams T, Lange F, Smith KJ, Tachtsidis I, Chataway J. Investigating cortical hypoxia in multiple sclerosis via time-domain near-infrared spectroscopy. Ann Clin Transl Neurol 2024. [PMID: 39037277 DOI: 10.1002/acn3.52150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2024] [Revised: 06/19/2024] [Accepted: 07/05/2024] [Indexed: 07/23/2024] Open
Abstract
OBJECTIVES Hypoperfusion and tissue hypoxia have been implicated as contributory mechanisms in the neuropathology of multiple sclerosis (MS). Our objective has been to study cortical oxygenation in vivo in patients with MS and age-matched controls. METHODS A custom, multiwavelength time-domain near-infrared spectroscopy system was developed for assessing tissue hypoxia from the prefrontal cortex. A cross-sectional case-control study was undertaken assessing patients with secondary progressive MS (SPMS) and age-matched controls. Co-registered magnetic resonance imaging was used to verify the location from which near-infrared spectroscopy data were obtained through Monte Carlo simulations of photon propagation. Additional clinical assessments of MS disease severity were carried out by trained neurologists. Linear mixed effect models were used to compare cortical oxygenation between cases and controls, and against measures of MS severity. RESULTS Thirty-three patients with secondary progressive MS (median expanded disability status scale 6 [IQR: 5-6.5]; median age 53.0 [IQR: 49-58]) and 20 age-matched controls were recruited. Modeling of photon propagation confirmed spectroscopy data were obtained from the prefrontal cortex. Patients with SPMS had significantly lower cortical hemoglobin oxygenation compared with controls (-6.0% [95% CI: -10.0 to -1.9], P = 0.004). There were no significant associations between cortical oxygenation and MS severity. INTERPRETATION Using an advanced, multiwavelength time-domain near-infrared spectroscopy system, we demonstrate that patients with SPMS have lower cortical oxygenation compared with controls.
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Affiliation(s)
- Thomas Williams
- UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Frédéric Lange
- Department of Medical Physics and Biomedical Engineering, University College London, London, UK
| | - Kenneth J Smith
- UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Ilias Tachtsidis
- Department of Medical Physics and Biomedical Engineering, University College London, London, UK
| | - Jeremy Chataway
- UCL Queen Square Institute of Neurology, University College London, London, UK
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Buzza A, Tapas K, Anders J, Jenkins M, Moffitt M. Photobiomodulation for pain relief: Model-based estimates of effective doses of light at the neural target. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2024; 256:112929. [PMID: 38759478 DOI: 10.1016/j.jphotobiol.2024.112929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Revised: 04/19/2024] [Accepted: 05/06/2024] [Indexed: 05/19/2024]
Abstract
INTRODUCTION Photobiomodulation (PBM) has been studied since the 1960s as a clinical tool. More recently, PBM has been observed to reduce compound action potential components and hypersensitivities associated with neuropathic pains. However, no definitive description of efficacious light parameters has been determined. Some reasons may be that previous meta-analyses and reviews have focused on emitter output rather than the light at the target tissue and have included data sets that are large but with notable variability (e.g., combining data from various disease etiologies, and data from PBM at various wavelengths). This fact has made it difficult to successfully define the range of effective parameters. METHODS In this study, photon propagation software was used to estimate irradiance at a target nerve using several published data sets chosen for their narrow criteria to minimize variability. Utilizing these estimates, effective and ineffective light irradiances at the nerve of interest for wavelengths of 633 nm or 808-830 nm were examined and estimated. These estimates are focused on the amount of light required to achieve a reduction in pain or a surrogate measure via a hypothesized nerve block mechanism. RESULTS Accounting for irradiance at the target nerve yielded a clear separation of PBM doses that achieved small-fiber nerve block from those that did not. For both the 633 nm group and the 808-830 group, the irradiance separation threshold followed a nonlinear path with respect to PBM application duration, where shorter durations required higher irradiances, and longer durations required lower irradiances. Using the same modeling methods, irradiance was estimated as a function of depth from a transcutaneous source (distance from skin surface) for emitter output power using small or large emitter sizes. CONCLUSION Taken together, the results of this study can be used to estimate effective PBM dosing schemes to achieve small-fiber inhibition for various anatomical scenarios.
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Affiliation(s)
- Andrew Buzza
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA.
| | - Kalista Tapas
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA
| | - Juanita Anders
- Department of Anatomy, Physiology, and Genetics, Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Michael Jenkins
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA; Department of Pediatrics, Case Western Reserve University, Cleveland, OH, USA
| | - Michael Moffitt
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA
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Blaney G, Sassaroli A, Fantini S. Spatial Sensitivity to Absorption Changes for Various Near-Infrared Spectroscopy Methods: A Compendium Review. JOURNAL OF INNOVATIVE OPTICAL HEALTH SCIENCES 2024; 17:2430001. [PMID: 39267952 PMCID: PMC11391891 DOI: 10.1142/s1793545824300015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/15/2024]
Abstract
This compendium review focuses on the spatial distribution of sensitivity to localized absorption changes in optically diffuse media, particularly for measurements relevant to near-infrared spectroscopy. The three temporal domains, continuous-wave, frequency-domain, and time-domain, each obtain different optical data-types whose changes may be related to effective homogeneous changes in the absorption coefficient. Sensitivity is the relationship between a localized perturbation and the recovered effective homogeneous absorption change. Therefore, spatial sensitivity maps representing the perturbation location can be generated for the numerous optical data-types in the three temporal domains. The review first presents a history of the past 30 years of work investigating this sensitivity in optically diffuse media. These works are experimental and theoretical, presenting 1-, 2-, and 3-dimensional sensitivity maps for different near-infrared spectroscopy methods, domains, and data-types. Following this history, we present a compendium of sensitivity maps organized by temporal domain and then data-type. This compendium provides a valuable tool to compare the spatial sensitivity of various measurement methods and parameters in one document. Methods for one to generate these maps are provided in the appendix, including code. This historical review and comprehensive sensitivity map compendium provides a single source researchers may use to visualize, investigate, compare, and generate sensitivity to localized absorption change maps.
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Affiliation(s)
- Giles Blaney
- Department of Biomedical Engineering, Tufts University 4 Colby St, Medford, MA 02155, USA
| | - Angelo Sassaroli
- Department of Biomedical Engineering, Tufts University 4 Colby St, Medford, MA 02155, USA
| | - Sergio Fantini
- Department of Biomedical Engineering, Tufts University 4 Colby St, Medford, MA 02155, USA
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Ioussoufovitch S, Diop M. Time-domain diffuse optical imaging technique for monitoring rheumatoid arthritis disease activity: experimental validation in tissue-mimicking finger phantoms. Phys Med Biol 2024; 69:125021. [PMID: 38830365 DOI: 10.1088/1361-6560/ad53a0] [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 treatment within 3-5 months of disease onset significantly improves rheumatoid arthritis (RA) prognosis. Nevertheless, 30% of RA patients fail their first treatment, and it takes 3-6 months to identify failure with current monitoring techniques. Time-domain diffuse optical imaging (TD-DOI) may be more sensitive to RA disease activity and could be used to detect treatment failure. In this report, we present the development of a TD-DOI hand imaging system and validate its ability to measure simulated changes in RA disease activity using tissue-mimicking finger phantoms.Approach.A TD-DOI system was built, based on a single-pixel camera architecture, and used to image solid phantoms which mimicked a proximal interphalangeal finger joint. For reference,in silicoimages of virtual models of the solid phantoms were also generated using Monte Carlo simulations. Spatiotemporal Fourier components were extracted from both simulated and experimental images, and their ability to distinguish between phantoms representing different RA disease activity was quantified.Main results.Many spatiotemporal Fourier components extracted from TD-DOI images could clearly distinguish between phantoms representing different states of RA disease activity.Significance.A TD-DOI system was built and validated using finger-mimicking solid phantoms. The findings suggest that the system could be used to monitor RA disease activity. This single-pixel TD-DOI system could be used to acquire longitudinal measures of RA disease activity to detect early treatment failure.
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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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Vera DA, García HA, Carbone NA, Waks-Serra MV, Iriarte DI, Pomarico JA. Retrieval of chromophore concentration changes in a digital human head model using analytical mean partial pathlengths of photons. JOURNAL OF BIOMEDICAL OPTICS 2024; 29:025004. [PMID: 38419755 PMCID: PMC10901244 DOI: 10.1117/1.jbo.29.2.025004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 01/25/2024] [Accepted: 01/26/2024] [Indexed: 03/02/2024]
Abstract
Significance Continuous-wave functional near-infrared spectroscopy has proved to be a valuable tool for assessing hemodynamic activity in the human brain in a non-invasively and inexpensive way. However, most of the current processing/analysis methods assume the head is a homogeneous medium, and hence do not appropriately correct for the signal coming from the scalp. This effect can be reduced by considering light propagation in a layered model of the human head, being the Monte Carlo (MC) simulations the gold standard to this end. However, this implies large computation times and demanding hardware capabilities. Aim In this work, we study the feasibility of replacing the homogeneous model and the MC simulations by means of analytical multilayered models, combining in this way, the speed and simplicity of implementation of the former with the robustness and accuracy of the latter. Approach Oxy- and deoxyhemoglobin (HbO and HbR, respectively) concentration changes were proposed in two different layers of a magnetic resonance imaging (MRI)-based meshed model of the human head, and then these changes were retrieved by means of (i) a typical homogeneous reconstruction and (ii) a theoretical layered reconstruction. Results Results suggest that the use of analytical models of light propagation in layered models outperforms the results obtained using traditional homogeneous reconstruction algorithms, providing much more accurate results for both, the extra- and the cerebral tissues. We also compare the analytical layered reconstruction with MC-based reconstructions, achieving similar degrees of accuracy, especially in the gray matter layer, but much faster (between 4 and 5 orders of magnitude). Conclusions We have successfully developed, implemented, and validated a method for retrieving chromophore concentration changes in the human brain, combining the simplicity and speed of the traditional homogeneous reconstruction algorithms with robustness and accuracy much more similar to those provided by MC simulations.
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Erdenedalai K, Maltais-Tariant R, Dehaes M, Boudoux C. MCOCT: an experimentally and numerically validated, open-source Monte Carlo simulator for optical coherence tomography. BIOMEDICAL OPTICS EXPRESS 2024; 15:624-640. [PMID: 38404350 PMCID: PMC10890866 DOI: 10.1364/boe.504061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 11/20/2023] [Accepted: 11/25/2023] [Indexed: 02/27/2024]
Abstract
Here, we present MCOCT, a Monte Carlo simulator for optical coherence tomography (OCT), incorporating a Gaussian illumination scheme and bias to increase backscattered event collection. MCOCT optical fluence was numerically compared and validated to an established simulator (MCX) and showed concordance at the focus while diverging slightly with distance to it. MCOCT OCT signals were experimentally compared and validated to OCT signals acquired in tissue-mimicking phantoms with known optical properties and showed a similar attenuation pattern with increasing depth while diverging beyond 1.5 mm and proximal to layer interfaces. MCOCT may help in the design of OCT systems for a wide range of applications.
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Affiliation(s)
- Khaliun Erdenedalai
- Polytechnique Montreal, Department of Engineering Physics, H3T 1J4, Montreal, Canada
| | | | - Mathieu Dehaes
- University of Montreal, Department of Radiology, Radio-oncology and Nuclear Medicine, H3T 1J4, Montreal, Canada
- Sainte-Justine University Hospital Center, Research Center, H3T 1C5, Montreal, Canada
- University of Montreal, Institute of Biomedical Engineering, H3T 1J4, Montreal, Canada
| | - Caroline Boudoux
- Polytechnique Montreal, Department of Engineering Physics, H3T 1J4, Montreal, Canada
- Sainte-Justine University Hospital Center, Research Center, H3T 1C5, Montreal, Canada
- Castor Optics, H3T 2B1, Montreal, Canada
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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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Robinson MB, Cheng TY, Renna M, Wu MM, Kim B, Cheng X, Boas DA, Franceschini MA, Carp SA. Comparing the performance potential of speckle contrast optical spectroscopy and diffuse correlation spectroscopy for cerebral blood flow monitoring using Monte Carlo simulations in realistic head geometries. NEUROPHOTONICS 2024; 11:015004. [PMID: 38282721 PMCID: PMC10821780 DOI: 10.1117/1.nph.11.1.015004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 12/13/2023] [Accepted: 01/08/2024] [Indexed: 01/30/2024]
Abstract
Significance The non-invasive measurement of cerebral blood flow based on diffuse optical techniques has seen increased interest as a research tool for cerebral perfusion monitoring in critical care and functional brain imaging. Diffuse correlation spectroscopy (DCS) and speckle contrast optical spectroscopy (SCOS) are two such techniques that measure complementary aspects of the fluctuating intensity signal, with DCS quantifying the temporal fluctuations of the signal and SCOS quantifying the spatial blurring of a speckle pattern. With the increasing interest in the use of these techniques, a thorough comparison would inform new adopters of the benefits of each technique. Aim We systematically evaluate the performance of DCS and SCOS for the measurement of cerebral blood flow. Approach Monte Carlo simulations of dynamic light scattering in an MRI-derived head model were performed. For both DCS and SCOS, estimates of sensitivity to cerebral blood flow changes, coefficient of variation of the measured blood flow, and the contrast-to-noise ratio of the measurement to the cerebral perfusion signal were calculated. By varying complementary aspects of data collection between the two methods, we investigated the performance benefits of different measurement strategies, including altering the number of modes per optical detector, the integration time/fitting time of the speckle measurement, and the laser source delivery strategy. Results Through comparison across these metrics with simulated detectors having realistic noise properties, we determine several guiding principles for the optimization of these techniques and report the performance comparison between the two over a range of measurement properties and tissue geometries. We find that SCOS outperforms DCS in terms of contrast-to-noise ratio for the cerebral blood flow signal in the ideal case simulated here but note that SCOS requires careful experimental calibrations to ensure accurate measurements of cerebral blood flow. Conclusion We provide design principles by which to evaluate the development of DCS and SCOS systems for their use in the measurement of cerebral blood flow.
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Affiliation(s)
- Mitchell B. Robinson
- Massachusetts General Hospital, Harvard Medical School, Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Boston, Massachusetts, United States
| | - Tom Y. Cheng
- Massachusetts General Hospital, Harvard Medical School, Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Boston, Massachusetts, United States
- Boston University, Neurophotonics Center, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - Marco Renna
- Massachusetts General Hospital, Harvard Medical School, Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Boston, Massachusetts, United States
| | - Melissa M. Wu
- Duke University, Department of Biomedical Engineering, Durham, North Carolina, United States
| | - Byungchan Kim
- Boston University, Neurophotonics Center, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - Xiaojun Cheng
- Boston University, Neurophotonics Center, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - David A. Boas
- Boston University, Neurophotonics Center, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - Maria Angela Franceschini
- Massachusetts General Hospital, Harvard Medical School, Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Boston, Massachusetts, United States
| | - Stefan A. Carp
- Massachusetts General Hospital, Harvard Medical School, Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Boston, Massachusetts, United States
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Tarvainen T, Cox B. Quantitative photoacoustic tomography: modeling and inverse problems. JOURNAL OF BIOMEDICAL OPTICS 2024; 29:S11509. [PMID: 38125717 PMCID: PMC10731766 DOI: 10.1117/1.jbo.29.s1.s11509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 11/19/2023] [Accepted: 11/28/2023] [Indexed: 12/23/2023]
Abstract
Significance Quantitative photoacoustic tomography (QPAT) exploits the photoacoustic effect with the aim of estimating images of clinically relevant quantities related to the tissue's optical absorption. The technique has two aspects: an acoustic part, where the initial acoustic pressure distribution is estimated from measured photoacoustic time-series, and an optical part, where the distributions of the optical parameters are estimated from the initial pressure. Aim Our study is focused on the optical part. In particular, computational modeling of light propagation (forward problem) and numerical solution methodologies of the image reconstruction (inverse problem) are discussed. Approach The commonly used mathematical models of how light and sound propagate in biological tissue are reviewed. A short overview of how the acoustic inverse problem is usually treated is given. The optical inverse problem and methods for its solution are reviewed. In addition, some limitations of real-life measurements and their effect on the inverse problems are discussed. Results An overview of QPAT with a focus on the optical part was given. Computational modeling and inverse problems of QPAT were addressed, and some key challenges were discussed. Furthermore, the developments for tackling these problems were reviewed. Although modeling of light transport is well-understood and there is a well-developed framework of inverse mathematics for approaching the inverse problem of QPAT, there are still challenges in taking these methodologies to practice. Conclusions Modeling and inverse problems of QPAT together were discussed. The scope was limited to the optical part, and the acoustic aspects were discussed only to the extent that they relate to the optical aspect.
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Affiliation(s)
- Tanja Tarvainen
- University of Eastern Finland, Department of Technical Physics, Kuopio, Finland
| | - Ben Cox
- University College London, Department of Medical Physics and Biomedical Engineering, London, United Kingdom
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Piersanti E, Rognes ME, Vinje V. Are brain displacements and pressures within the parenchyma induced by surface pressure differences? A computational modelling study. PLoS One 2023; 18:e0288668. [PMID: 38150460 PMCID: PMC10752538 DOI: 10.1371/journal.pone.0288668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Accepted: 06/30/2023] [Indexed: 12/29/2023] Open
Abstract
The intracranial pressure is implicated in many homeostatic processes in the brain and is a fundamental parameter in several diseases such as e.g. idiopathic normal pressure hydrocephalus. The presence of a small but persistent pulsatile intracranial pulsatile transmantle pressure gradient (on the order of a few mmHg/m at peak) has recently been demonstrated in hydrocephalus subjects. A key question is whether pulsatile intracranial pressure and displacements can be induced by a small pressure gradient originating from the brain surface alone. In this study, we model the brain parenchyma as either a linearly elastic or a poroelastic medium, and impose a pulsatile pressure gradient acting between the ventricular and the pial surfaces but no additional external forces. Using this high-resolution physics-based model, we use in vivo pulsatile pressure gradients from subjects with idiopathic normal pressure hydrocephalus to compute parenchyma displacement, volume change, fluid pressure, and fluid flux. The resulting displacement field is pulsatile and in qualitatively and quantitatively good agreement with the literature, both with elastic and poroelastic models. However, the pulsatile forces on the boundaries are not sufficient for pressure pulse propagation through the brain parenchyma. Our results suggest that pressure differences at the brain surface, originating e.g. from pulsating arteries surrounding the brain, are not alone sufficient to drive interstitial fluid flow within the brain parenchyma and that potential pressure gradients found within the parenchyma rather arise from a large portion of the blood vessel network, including smaller blood vessels within the brain parenchyma itself.
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Affiliation(s)
- Eleonora Piersanti
- Simula Research Laboratory, Oslo, Norway
- Expert Analytics AS, Oslo, Norway
| | | | - Vegard Vinje
- Simula Research Laboratory, Oslo, Norway
- Expert Analytics AS, Oslo, Norway
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Cortese L, Fernández Esteberena P, Zanoletti M, Lo Presti G, Aranda Velazquez G, Ruiz Janer S, Buttafava M, Renna M, Di Sieno L, Tosi A, Dalla Mora A, Wojtkiewicz S, Dehghani H, de Fraguier S, Nguyen-Dinh A, Rosinski B, Weigel UM, Mesquida J, Squarcia M, Hanzu FA, Contini D, Mora Porta M, Durduran T. In vivocharacterization of the optical and hemodynamic properties of the human sternocleidomastoid muscle through ultrasound-guided hybrid near-infrared spectroscopies. Physiol Meas 2023; 44:125010. [PMID: 38061053 DOI: 10.1088/1361-6579/ad133a] [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: 06/13/2023] [Accepted: 12/07/2023] [Indexed: 12/28/2023]
Abstract
Objective.In this paper, we present a detailedin vivocharacterization of the optical and hemodynamic properties of the human sternocleidomastoid muscle (SCM), obtained through ultrasound-guided near-infrared time-domain and diffuse correlation spectroscopies.Approach.A total of sixty-five subjects (forty-nine females, sixteen males) among healthy volunteers and thyroid nodule patients have been recruited for the study. Their SCM hemodynamic (oxy-, deoxy- and total hemoglobin concentrations, blood flow, blood oxygen saturation and metabolic rate of oxygen extraction) and optical properties (wavelength dependent absorption and reduced scattering coefficients) have been measured by the use of a novel hybrid device combining in a single unit time-domain near-infrared spectroscopy, diffuse correlation spectroscopy and simultaneous ultrasound imaging.Main results.We provide detailed tables of the results related to SCM baseline (i.e. muscle at rest) properties, and reveal significant differences on the measured parameters due to variables such as side of the neck, sex, age, body mass index, depth and thickness of the muscle, allowing future clinical studies to take into account such dependencies.Significance.The non-invasive monitoring of the hemodynamics and metabolism of the sternocleidomastoid muscle during respiration became a topic of increased interest partially due to the increased use of mechanical ventilation during the COVID-19 pandemic. Near-infrared diffuse optical spectroscopies were proposed as potential practical monitors of increased recruitment of SCM during respiratory distress. They can provide clinically relevant information on the degree of the patient's respiratory effort that is needed to maintain an optimal minute ventilation, with potential clinical application ranging from evaluating chronic pulmonary diseases to more acute settings, such as acute respiratory failure, or to determine the readiness to wean from invasive mechanical ventilation.
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Affiliation(s)
- Lorenzo Cortese
- ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, E-08860 Castelldefels (Barcelona), Spain
| | - Pablo Fernández Esteberena
- ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, E-08860 Castelldefels (Barcelona), Spain
| | - Marta Zanoletti
- ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, E-08860 Castelldefels (Barcelona), Spain
- Politecnico di Milano, Dipartimento di Fisica, I-20133 Milano, Italy
| | - Giuseppe Lo Presti
- ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, E-08860 Castelldefels (Barcelona), Spain
| | | | - Sabina Ruiz Janer
- IDIBAPS, Fundació Clínic per la Recerca Biomèdica, E-08036 Barcelona, Spain
| | - Mauro Buttafava
- Politecnico di Milano, Dipartimento di Elettronica Informazione e Bioingegneria, I-20133 Milano, Italy
- Now at PIONIRS s.r.l., I-20124 Milano, Italy
| | - Marco Renna
- Politecnico di Milano, Dipartimento di Elettronica Informazione e Bioingegneria, I-20133 Milano, Italy
- Now at Athinoula A. Martinos Center for Biomedical Imaging, MGH, Harvard Medical School, Charlestown, MA 02129, United States of America
| | - Laura Di Sieno
- Politecnico di Milano, Dipartimento di Fisica, I-20133 Milano, Italy
| | - Alberto Tosi
- Politecnico di Milano, Dipartimento di Elettronica Informazione e Bioingegneria, I-20133 Milano, Italy
| | | | - Stanislaw Wojtkiewicz
- University of Birmingham, School of Computer Science, Edgbaston, Birmingham, B15 2TT, United Kingdom
- Now at Nalecz Institute of Biocybernetics and Biomedical Engineering, 02-109 Warsaw, Poland
| | - Hamid Dehghani
- University of Birmingham, School of Computer Science, Edgbaston, Birmingham, B15 2TT, United Kingdom
| | | | | | | | - Udo M Weigel
- HemoPhotonics S.L., E-08860 Castelldefels (Barcelona), Spain
| | - Jaume Mesquida
- Área de Crítics, Parc Taulí Hospital Universitari, E-08208 Sabadell, Spain
| | - Mattia Squarcia
- IDIBAPS, Fundació Clínic per la Recerca Biomèdica, E-08036 Barcelona, Spain
- Neuroradiology Department, Hospital Clínic of Barcelona, E-08036 Barcelona, Spain
| | - Felicia A Hanzu
- IDIBAPS, Fundació Clínic per la Recerca Biomèdica, E-08036 Barcelona, Spain
- Endocrinology and Nutrition Department, Hospital Clínic of Barcelona, E-08036 Barcelona, Spain
- Centro de Investigación Biomédica en Red Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), E-28029 Madrid, Spain
| | - Davide Contini
- Politecnico di Milano, Dipartimento di Fisica, I-20133 Milano, Italy
| | - Mireia Mora Porta
- IDIBAPS, Fundació Clínic per la Recerca Biomèdica, E-08036 Barcelona, Spain
- Endocrinology and Nutrition Department, Hospital Clínic of Barcelona, E-08036 Barcelona, Spain
- Centro de Investigación Biomédica en Red Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), E-28029 Madrid, Spain
| | - Turgut Durduran
- ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, E-08860 Castelldefels (Barcelona), Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), E-08010 Barcelona, Spain
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14
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Zhuo J, Weidrick CE, Liu Y, Moffitt MA, Jansen ED, Chiel HJ, Jenkins MW. Selective Infrared Neural Inhibition Can Be Reproduced by Resistive Heating. Neuromodulation 2023; 26:1757-1771. [PMID: 36707292 PMCID: PMC10366334 DOI: 10.1016/j.neurom.2022.12.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 11/22/2022] [Accepted: 12/06/2022] [Indexed: 01/26/2023]
Abstract
OBJECTIVES Small-diameter afferent axons carry various sensory signals that are critical for vital physiological conditions but sometimes contribute to pathologies. Infrared (IR) neural inhibition (INI) can induce selective heat block of small-diameter axons, which holds potential for translational applications such as pain management. Previous research suggested that IR-heating-induced acceleration of voltage-gated potassium channel kinetics is the mechanism for INI. Therefore, we hypothesized that other heating methods, such as resistive heating (RH) in a cuff, could reproduce the selective inhibition observed in INI. MATERIALS AND METHODS We conducted ex vivo nerve-heating experiments on pleural-abdominal connective nerves of Aplysia californica using both IR and RH. We fabricated a transparent silicone nerve cuff for simultaneous IR heating, RH, and temperature measurements. Temperature elevations (ΔT) on the nerve surface were recorded for both heating modalities, which were tested over a range of power levels that cover a similar ΔT range. We recorded electrically evoked compound action potentials (CAPs) and segmented them into fast and slow subcomponents on the basis of conduction velocity differences between the large and small-diameter axonal subpopulations. We calculated the normalized inhibition strength and inhibition selectivity index on the basis of the rectified area under the curve of each subpopulation. RESULTS INI and RH showed a similar selective inhibition effect on CAP subcomponents for slow-conducting axons, confirmed by the inhibition probability vs ΔT dose-response curve based on approximately 2000 CAP measurements. The inhibition selectivity indexes of the two heating modalities were similar across six nerves. RH only required half the total electrical power required by INI to achieve a similar ΔT. SIGNIFICANCE We show that selective INI can be reproduced by other heating modalities such as RH. RH, because of its high energy efficiency and simple design, can be a good candidate for future implantable neural interface designs.
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Affiliation(s)
- Junqi Zhuo
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA
| | - Chloe E Weidrick
- Department of Nutrition, Case Western Reserve University, Cleveland, OH, USA
| | - Yehe Liu
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA
| | - Michael A Moffitt
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA
| | - E Duco Jansen
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA; Biophotonics Center, Vanderbilt University, Nashville, TN, USA; Department of Neurological Surgery, Vanderbilt University, Nashville, TN, USA
| | - Hillel J Chiel
- Department of Biology, Case Western Reserve University, Cleveland OH, USA; Department of Neurosciences, Case Western Reserve University, Cleveland, OH, USA; Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA
| | - Michael W Jenkins
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA; Department of Pediatrics, Case Western Reserve University, Cleveland, OH, USA.
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15
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Diao Y, Liu L, Deng N, Lyu S, Hirata A. Tensor-conductance model for reducing the computational artifact in target tissue for low-frequency dosimetry. Phys Med Biol 2023; 68:205014. [PMID: 37722382 DOI: 10.1088/1361-6560/acfae0] [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: 06/07/2023] [Accepted: 09/18/2023] [Indexed: 09/20/2023]
Abstract
Objective.In protecting human from low-frequency (<100 kHz) exposure, an induced electric field strength is used as a physical quantity for assessment. However, the computational assessment suffers from a staircasing error because of the approximation of curved boundary discretized with cubic voxels. The international guidelines consider an additional reduction factor of 3 when setting the limit of external field strength computed from the permissible induced electric field. Here, a new method was proposed to reduce the staircasing error considering the tensor conductance in human modeling for low-frequency dosimetry.Approach.We proposed a tensor-based conductance model, which was developed on the basis of the filling ratio and the direction of the tissue interface to satisfy the electric field boundary condition and reduce staircasing errors in the target tissue of a voxel human model.Main results.The proposed model was validated using two-layer nonconcentric cylindrical and spherical models with different conductivity contrasts. A comparison of induced electric field strengths with solutions obtained using an analytical formula and finite element method simulation indicated that for a wide range of conductivity ratios, staircasing errors were reduced compared with a conventional scalar-potential finite-difference method. The induced electric field in a simple anatomical head model using our approach was in good agreement with finite element method for exposure to uniform magnetic field exposure and that from coil, simulating transcranial magnetic stimulation.Significance.The proposed tensor-conductance model demonstrated that the staircasing error in an inner target tissue of a voxel human body can be reduced. This finding can be used for the electromagnetic compliance assessment and dose evaluation in electric or magnetic stimulation at low frequencies.
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Affiliation(s)
- Yinliang Diao
- College of Electronic Engineering, College of Artificial Intelligence, South China Agricultural University, Guangzhou 510642, People's Republic of China
- Department of Electrical and Mechanical Engineering, Nagoya Institute of Technology, Nagoya 466-8555, Japan
| | - Li Liu
- College of Electronic Engineering, College of Artificial Intelligence, South China Agricultural University, Guangzhou 510642, People's Republic of China
| | - Nuo Deng
- College of Electronic Engineering, College of Artificial Intelligence, South China Agricultural University, Guangzhou 510642, People's Republic of China
| | - Shilei Lyu
- College of Electronic Engineering, College of Artificial Intelligence, South China Agricultural University, Guangzhou 510642, People's Republic of China
| | - Akimasa Hirata
- Department of Electrical and Mechanical Engineering, Nagoya Institute of Technology, Nagoya 466-8555, Japan
- Center of Biomedical Physics and Information Technology, Nagoya Institute of Technology, Nagoya 466-8555, Japan
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16
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Wu MM, Horstmeyer R, Carp SA. scatterBrains: an open database of human head models and companion optode locations for realistic Monte Carlo photon simulations. JOURNAL OF BIOMEDICAL OPTICS 2023; 28:100501. [PMID: 37811478 PMCID: PMC10557038 DOI: 10.1117/1.jbo.28.10.100501] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 09/21/2023] [Accepted: 09/23/2023] [Indexed: 10/10/2023]
Abstract
Significance Monte Carlo (MC) simulations are currently the gold standard in the near-infrared and diffuse correlation spectroscopy (NIRS/DCS) communities for generating light transport paths through tissue. However, realistic and diverse models that capture complex tissue layers are not easily available to all; moreover, manually placing optodes on such models can be tedious and time consuming. Such limitations may hinder the adoption of representative models for basic simulations and the use of these models for large-scale simulations, e.g., for training machine learning algorithms. Aim We aim to provide the NIRS/DCS communities with an open-source, user-friendly database of morphologically and optically realistic head models, as well as a succinct software pipeline to prepare these models for mesh-based Monte Carlo simulations of light transport. Approach Sixteen anatomical models were created from segmented T1-weighted magnetic resonance imaging (MRI) head scans and converted to tetrahedral mesh volumes. Approximately 800 companion scalp surface locations were distributed on each model, comprising full head coverage. A pipeline was created to place custom source and optical detectors at each location, and guidance is provided on how to use these parameters to set up MC simulations. Results The models, head surface locations, and all associated code are freely available under the scatterBrains project on Github. Conclusions The NIRS/DCS community benefits from having shared resources for conducting MC simulations on realistic head geometries. We hope this will make MRI-based head models and virtual optode placement easily accessible to all. Contributions to the database are welcome and encouraged.
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Affiliation(s)
- Melissa M. Wu
- Duke University, Department of Biomedical Engineering, Durham, North Carolina, United States
- Massachusetts General Hospital, Harvard Medical School, Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, Massachusetts, United States
| | - Roarke Horstmeyer
- Duke University, Department of Biomedical Engineering, Durham, North Carolina, United States
| | - Stefan A. Carp
- Massachusetts General Hospital, Harvard Medical School, Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, Massachusetts, United States
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17
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Rix T, Dreher KK, Nölke JH, Schellenberg M, Tizabi MD, Seitel A, Maier-Hein L. Efficient Photoacoustic Image Synthesis with Deep Learning. SENSORS (BASEL, SWITZERLAND) 2023; 23:7085. [PMID: 37631628 PMCID: PMC10457787 DOI: 10.3390/s23167085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 07/25/2023] [Accepted: 08/07/2023] [Indexed: 08/27/2023]
Abstract
Photoacoustic imaging potentially allows for the real-time visualization of functional human tissue parameters such as oxygenation but is subject to a challenging underlying quantification problem. While in silico studies have revealed the great potential of deep learning (DL) methodology in solving this problem, the inherent lack of an efficient gold standard method for model training and validation remains a grand challenge. This work investigates whether DL can be leveraged to accurately and efficiently simulate photon propagation in biological tissue, enabling photoacoustic image synthesis. Our approach is based on estimating the initial pressure distribution of the photoacoustic waves from the underlying optical properties using a back-propagatable neural network trained on synthetic data. In proof-of-concept studies, we validated the performance of two complementary neural network architectures, namely a conventional U-Net-like model and a Fourier Neural Operator (FNO) network. Our in silico validation on multispectral human forearm images shows that DL methods can speed up image generation by a factor of 100 when compared to Monte Carlo simulations with 5×108 photons. While the FNO is slightly more accurate than the U-Net, when compared to Monte Carlo simulations performed with a reduced number of photons (5×106), both neural network architectures achieve equivalent accuracy. In contrast to Monte Carlo simulations, the proposed DL models can be used as inherently differentiable surrogate models in the photoacoustic image synthesis pipeline, allowing for back-propagation of the synthesis error and gradient-based optimization over the entire pipeline. Due to their efficiency, they have the potential to enable large-scale training data generation that can expedite the clinical application of photoacoustic imaging.
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Affiliation(s)
- Tom Rix
- Division of Intelligent Medical Systems, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 223, 69120 Heidelberg, Germany
- Faculty of Mathematics and Computer Sciences, Heidelberg University, 69120 Heidelberg, Germany
| | - Kris K. Dreher
- Division of Intelligent Medical Systems, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 223, 69120 Heidelberg, Germany
- Faculty of Physics and Astronomy, Heidelberg University, 69120 Heidelberg, Germany
| | - Jan-Hinrich Nölke
- Division of Intelligent Medical Systems, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 223, 69120 Heidelberg, Germany
- Faculty of Mathematics and Computer Sciences, Heidelberg University, 69120 Heidelberg, Germany
| | - Melanie Schellenberg
- Division of Intelligent Medical Systems, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 223, 69120 Heidelberg, Germany
- Faculty of Mathematics and Computer Sciences, Heidelberg University, 69120 Heidelberg, Germany
- HIDSS4Health—Helmholtz Information and Data Science School for Health, 69120 Heidelberg, Germany
- National Center for Tumor Diseases (NCT), NCT Heidelberg, a partnership between DKFZ and University Medical Center Heidelberg, 69120 Heidelberg, Germany
| | - Minu D. Tizabi
- Division of Intelligent Medical Systems, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 223, 69120 Heidelberg, Germany
- National Center for Tumor Diseases (NCT), NCT Heidelberg, a partnership between DKFZ and University Medical Center Heidelberg, 69120 Heidelberg, Germany
| | - Alexander Seitel
- Division of Intelligent Medical Systems, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 223, 69120 Heidelberg, Germany
- National Center for Tumor Diseases (NCT), NCT Heidelberg, a partnership between DKFZ and University Medical Center Heidelberg, 69120 Heidelberg, Germany
| | - Lena Maier-Hein
- Division of Intelligent Medical Systems, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 223, 69120 Heidelberg, Germany
- Faculty of Mathematics and Computer Sciences, Heidelberg University, 69120 Heidelberg, Germany
- HIDSS4Health—Helmholtz Information and Data Science School for Health, 69120 Heidelberg, Germany
- National Center for Tumor Diseases (NCT), NCT Heidelberg, a partnership between DKFZ and University Medical Center Heidelberg, 69120 Heidelberg, Germany
- Medical Faculty, Heidelberg University, 69120 Heidelberg, Germany
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18
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Pattyn A, Yan Y, Mehrmohammadi M. Wavelength-dependent error minimization for quantitative spectroscopic photoacoustic tomography with a ring-array system. Z Med Phys 2023; 33:444-451. [PMID: 37225605 PMCID: PMC10517392 DOI: 10.1016/j.zemedi.2023.04.005] [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: 11/07/2022] [Revised: 03/31/2023] [Accepted: 04/06/2023] [Indexed: 05/26/2023]
Abstract
PURPOSE Photoacoustic tomography (PAT) is a non-invasive and high-resolution imaging technique that can provide functional and molecular information from the optical properties of pathological tissues, such as cancer. Spectroscopic PAT (sPAT) is capable of supplying information such as oxygen saturation (sO2), which is an important biological indicator for diseases such as cancer. However, the wavelength dependent nature of sPAT makes it challenging to provide accurate quantitative measurements of tissue oxygenation beyond shallow depths. We have previously reported the utility of combined ultrasound tomography and PAT to achieve optical and acoustic compensated PAT images at a single wavelength and for enhanced PAT images at larger depths. In this work we further explore the utility of the optical and acoustic compensation PAT algorithm to minimize the wavelength dependency in sPAT by showcasing improvements in spectral unmixing. MATERIALS AND METHODS Two optically and acoustically characterized heterogenous phantoms were manufactured to test the ability of the system and developed algorithm to minimize the wavelength-dependence driven error in sPAT spectral unmixing. The PA inclusions within each phantom were composed of a mixture of two sulfate dyes, copper sulfate (CuSO4) and nickel sulfate (NiSO4), with known optical spectra. Improvements between uncompensated and optically and acoustically compensated PAT (OAcPAT) were quantified as the relative percent error between the measured results and the ground truth. RESULTS The results of our phantom studies demonstrate that OAcPAT can significantly improve the accuracy of sPAT measurements in a heterogenous medium and especially at larger inclusions depths which can reach to up to 12% improvement in measurement errors. This significant improvement can play a vital role in reliability of future in-vivo biomarker quantifications. CONCLUSIONS Utilizing UST for model-based optical and acoustic compensation of PAT images was proposed by our group previously. In this work, we further demonstrated the efficacy of the developed algorithm in sPAT by minimizing the error caused by the tissue's optical heterogeneity on improving spectral unmixing, which is a major limiting factor in reliability of sPAT measurements. Such synergistic combination of UST and PAT provides a window of opportunity to achieve bias-free quantitative sPAT measurements, which plays an important role in future pre-clinical and clinical utility of PAT.
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Affiliation(s)
- Alexander Pattyn
- Department of Biomedical Engineering, Wayne State University, Detroit, MI, USA
| | - Yan Yan
- Department of Imaging Sciences, University of Rochester Medical Center, Rochester, NY, USA
| | - Mohammad Mehrmohammadi
- Department of Imaging Sciences, University of Rochester Medical Center, Rochester, NY, USA; Department of Biomedical Engineering, University of Rochester, Rochester, NY, USA; Department of Electrical and Computer Engineering, University of Rochester, Rochester, NY, USA; Wilmot Cancer Institute, University of Rochester Medical Center, Rochester, NY, USA.
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19
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Hirvi P, Kuutela T, Fang Q, Hannukainen A, Hyvönen N, Nissilä I. Effects of atlas-based anatomy on modelled light transport in the neonatal head. Phys Med Biol 2023; 68:135019. [PMID: 37167982 PMCID: PMC10460200 DOI: 10.1088/1361-6560/acd48c] [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: 11/08/2022] [Revised: 04/21/2023] [Accepted: 05/11/2023] [Indexed: 05/13/2023]
Abstract
Objective.Diffuse optical tomography (DOT) provides a relatively convenient method for imaging haemodynamic changes related to neuronal activity on the cerebral cortex. Due to practical challenges in obtaining anatomical images of neonates, an anatomical framework is often created from an age-appropriate atlas model, which is individualized to the subject based on measurements of the head geometry. This work studies the approximation error arising from using an atlas instead of the neonate's own anatomical model.Approach.We consider numerical simulations of frequency-domain (FD) DOT using two approaches, Monte Carlo simulations and diffusion approximation via finite element method, and observe the variation in (1) the logarithm of amplitude and phase shift measurements, and (2) the corresponding inner head sensitivities (Jacobians), due to varying segmented anatomy. Varying segmentations are sampled by registering 165 atlas models from a neonatal database to the head geometry of one individual selected as the reference model. Prior to the registration, we refine the segmentation of the cerebrospinal fluid (CSF) by separating the CSF into two physiologically plausible layers.Main results.In absolute measurements, a considerable change in the grey matter or extracerebral tissue absorption coefficient was found detectable over the anatomical variation. In difference measurements, a small local 10%-increase in brain absorption was clearly detectable in the simulated measurements over the approximation error in the Jacobians, despite the wide range of brain maturation among the registered models.Significance.Individual-level atlas models could potentially be selected within several weeks in gestational age in DOT difference imaging, if an exactly age-appropriate atlas is not available. The approximation error method could potentially be implemented to improve the accuracy of atlas-based imaging. The presented CSF segmentation algorithm could be useful also in other model-based imaging modalities. The computation of FD Jacobians is now available in the widely-used Monte Carlo eXtreme software.
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Affiliation(s)
- Pauliina Hirvi
- Aalto University, Department of
Mathematics and Systems Analysis, PO Box 11100, FI-00076 AALTO,
Finland
| | - Topi Kuutela
- Aalto University, Department of
Mathematics and Systems Analysis, PO Box 11100, FI-00076 AALTO,
Finland
| | - Qianqian Fang
- Northeastern University, Department of
Bioengineering, 360 Huntington Ave, Boston, MA 02115, United States of
America
| | - Antti Hannukainen
- Aalto University, Department of
Mathematics and Systems Analysis, PO Box 11100, FI-00076 AALTO,
Finland
| | - Nuutti Hyvönen
- Aalto University, Department of
Mathematics and Systems Analysis, PO Box 11100, FI-00076 AALTO,
Finland
| | - Ilkka Nissilä
- Aalto University, Department of
Neuroscience and Biomedical Engineering, PO Box 12200, FI-00076 AALTO,
Finland
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20
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Forti RM, Hobson LJ, Benson EJ, Ko TS, Ranieri NR, Laurent G, Weeks MK, Widmann NJ, Morton S, Davis AM, Sueishi T, Lin Y, Wulwick KS, Fagan N, Shin SS, Kao SH, Licht DJ, White BR, Kilbaugh TJ, Yodh AG, Baker WB. Non-invasive diffuse optical monitoring of cerebral physiology in an adult swine-model of impact traumatic brain injury. BIOMEDICAL OPTICS EXPRESS 2023; 14:2432-2448. [PMID: 37342705 PMCID: PMC10278631 DOI: 10.1364/boe.486363] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 03/17/2023] [Accepted: 04/12/2023] [Indexed: 06/23/2023]
Abstract
In this study, we used diffuse optics to address the need for non-invasive, continuous monitoring of cerebral physiology following traumatic brain injury (TBI). We combined frequency-domain and broadband diffuse optical spectroscopy with diffuse correlation spectroscopy to monitor cerebral oxygen metabolism, cerebral blood volume, and cerebral water content in an established adult swine-model of impact TBI. Cerebral physiology was monitored before and after TBI (up to 14 days post injury). Overall, our results suggest that non-invasive optical monitoring can assess cerebral physiologic impairments post-TBI, including an initial reduction in oxygen metabolism, development of cerebral hemorrhage/hematoma, and brain swelling.
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Affiliation(s)
- Rodrigo M. Forti
- Division of Neurology, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Resuscitation Science Center of Emphasis, CHOP Research Institute, Philadelphia, PA 19104, USA
| | - Lucas J. Hobson
- Resuscitation Science Center of Emphasis, CHOP Research Institute, Philadelphia, PA 19104, USA
- Department of Anesthesiology and Critical Care Medicine, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Emilie J. Benson
- Division of Neurology, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Tiffany S. Ko
- Resuscitation Science Center of Emphasis, CHOP Research Institute, Philadelphia, PA 19104, USA
- Department of Anesthesiology and Critical Care Medicine, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Nicolina R. Ranieri
- Division of Neurology, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Resuscitation Science Center of Emphasis, CHOP Research Institute, Philadelphia, PA 19104, USA
| | - Gerard Laurent
- Division of Neurology, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Resuscitation Science Center of Emphasis, CHOP Research Institute, Philadelphia, PA 19104, USA
| | - M. Katie Weeks
- Resuscitation Science Center of Emphasis, CHOP Research Institute, Philadelphia, PA 19104, USA
- Department of Anesthesiology and Critical Care Medicine, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Nicholas J. Widmann
- Resuscitation Science Center of Emphasis, CHOP Research Institute, Philadelphia, PA 19104, USA
- Department of Anesthesiology and Critical Care Medicine, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Sarah Morton
- Resuscitation Science Center of Emphasis, CHOP Research Institute, Philadelphia, PA 19104, USA
- Department of Anesthesiology and Critical Care Medicine, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Anthony M. Davis
- Resuscitation Science Center of Emphasis, CHOP Research Institute, Philadelphia, PA 19104, USA
- Department of Anesthesiology and Critical Care Medicine, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Takayuki Sueishi
- Resuscitation Science Center of Emphasis, CHOP Research Institute, Philadelphia, PA 19104, USA
- Department of Anesthesiology and Critical Care Medicine, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Yuxi Lin
- Resuscitation Science Center of Emphasis, CHOP Research Institute, Philadelphia, PA 19104, USA
- Department of Anesthesiology and Critical Care Medicine, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Karli S. Wulwick
- Resuscitation Science Center of Emphasis, CHOP Research Institute, Philadelphia, PA 19104, USA
- Department of Anesthesiology and Critical Care Medicine, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Nicholas Fagan
- Resuscitation Science Center of Emphasis, CHOP Research Institute, Philadelphia, PA 19104, USA
- Department of Anesthesiology and Critical Care Medicine, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Samuel S. Shin
- Resuscitation Science Center of Emphasis, CHOP Research Institute, Philadelphia, PA 19104, USA
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Shih-Han Kao
- Resuscitation Science Center of Emphasis, CHOP Research Institute, Philadelphia, PA 19104, USA
- Department of Anesthesiology and Critical Care Medicine, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Daniel J. Licht
- Division of Neurology, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Brian R. White
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Division of Cardiology, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Todd J. Kilbaugh
- Resuscitation Science Center of Emphasis, CHOP Research Institute, Philadelphia, PA 19104, USA
- Department of Anesthesiology and Critical Care Medicine, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Arjun G. Yodh
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Wesley B. Baker
- Division of Neurology, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Resuscitation Science Center of Emphasis, CHOP Research Institute, Philadelphia, PA 19104, USA
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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21
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Phillips V Z, Canoy RJ, Paik SH, Lee SH, Kim BM. Functional Near-Infrared Spectroscopy as a Personalized Digital Healthcare Tool for Brain Monitoring. J Clin Neurol 2023; 19:115-124. [PMID: 36854332 PMCID: PMC9982178 DOI: 10.3988/jcn.2022.0406] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 11/17/2022] [Accepted: 11/18/2022] [Indexed: 03/02/2023] Open
Abstract
The sustained growth of digital healthcare in the field of neurology relies on portable and cost-effective brain monitoring tools that can accurately monitor brain function in real time. Functional near-infrared spectroscopy (fNIRS) is one such tool that has become popular among researchers and clinicians as a practical alternative to functional magnetic resonance imaging, and as a complementary tool to modalities such as electroencephalography. This review covers the contribution of fNIRS to the personalized goals of digital healthcare in neurology by identifying two major trends that drive current fNIRS research. The first major trend is multimodal monitoring using fNIRS, which allows clinicians to access more data that will help them to understand the interconnection between the cerebral hemodynamics and other physiological phenomena in patients. This allows clinicians to make an overall assessment of physical health to obtain a more-detailed and individualized diagnosis. The second major trend is that fNIRS research is being conducted with naturalistic experimental paradigms that involve multisensory stimulation in familiar settings. Cerebral monitoring of multisensory stimulation during dynamic activities or within virtual reality helps to understand the complex brain activities that occur in everyday life. Finally, the scope of future fNIRS studies is discussed to facilitate more-accurate assessments of brain activation and the wider clinical acceptance of fNIRS as a medical device for digital healthcare.
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Affiliation(s)
- Zephaniah Phillips V
- Global Health Technology Research Center, College of Health Science, Korea University, Seoul, Korea.
| | - Raymart Jay Canoy
- Program in Biomicro System Technology, College of Engineering, Korea University, Seoul, Korea
| | - Seung-Ho Paik
- Global Health Technology Research Center, College of Health Science, Korea University, Seoul, Korea
- KLIEN Inc., Seoul Biohub, Seoul, Korea
| | - Seung Hyun Lee
- Interdisciplinary Program in Precision Public Health, Korea University, Seoul, Korea
| | - Beop-Min Kim
- Department of Bio-Convergence Engineering, Korea University, Seoul, Korea
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22
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Kelsey CM, Modico MA, Richards JE, Enlow MB, Nelson CA. Frontal asymmetry assessed in infancy using functional near-infrared spectroscopy is associated with emotional and behavioral problems in early childhood. Child Dev 2023; 94:563-578. [PMID: 36428283 PMCID: PMC9992105 DOI: 10.1111/cdev.13877] [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] [Indexed: 11/27/2022]
Abstract
Frontal asymmetry (FA), the difference in brain activity between the left versus right frontal areas, is thought to reflect approach versus avoidance motivation. This study (2012-2021) used functional near-infrared spectroscopy to investigate if infant (Mage = 7.63 months; N = 90; n = 48 male; n = 75 White) FA in the dorsolateral prefrontal cortex relates to psychopathology in later childhood (Mage = 62.05 months). Greater right FA to happy faces was associated with increased internalizing (η2 = .09) and externalizing (η2 = .06) problems at age 5 years. Greater right FA to both happy and fearful faces was associated with an increased likelihood of a lifetime anxiety diagnosis (R2 > .13). FA may be an informative and early-emerging marker for psychopathology.
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Affiliation(s)
- Caroline M. Kelsey
- Department of Pediatrics, Division of Developmental Medicine, Boston Children’s Hospital, Boston, MA, United States
- Department of Pediatrics, Harvard Medical School, Boston, MA, United States
| | - Margaret A. Modico
- Department of Pediatrics, Division of Developmental Medicine, Boston Children’s Hospital, Boston, MA, United States
| | - John E. Richards
- Department of Psychology, University of South Carolina, Columbia, SC, United States
| | - Michelle Bosquet Enlow
- Department of Psychiatry and Behavioral Sciences, Boston Children’s Hospital, Boston, MA, United States
- Department of Psychiatry, Harvard Medical School, Boston, MA, United States
| | - Charles A. Nelson
- Department of Pediatrics, Division of Developmental Medicine, Boston Children’s Hospital, Boston, MA, United States
- Department of Pediatrics, Harvard Medical School, Boston, MA, United States
- Harvard Graduate School of Education, Cambridge, MA, United States
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23
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You S, Xiang Y, Hwang HH, Berry DB, Kiratitanaporn W, Guan J, Yao E, Tang M, Zhong Z, Ma X, Wangpraseurt D, Sun Y, Lu TY, Chen S. High cell density and high-resolution 3D bioprinting for fabricating vascularized tissues. SCIENCE ADVANCES 2023; 9:eade7923. [PMID: 36812321 PMCID: PMC9946358 DOI: 10.1126/sciadv.ade7923] [Citation(s) in RCA: 34] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Accepted: 01/24/2023] [Indexed: 06/18/2023]
Abstract
Three-dimensional (3D) bioprinting techniques have emerged as the most popular methods to fabricate 3D-engineered tissues; however, there are challenges in simultaneously satisfying the requirements of high cell density (HCD), high cell viability, and fine fabrication resolution. In particular, bioprinting resolution of digital light processing-based 3D bioprinting suffers with increasing bioink cell density due to light scattering. We developed a novel approach to mitigate this scattering-induced deterioration of bioprinting resolution. The inclusion of iodixanol in the bioink enables a 10-fold reduction in light scattering and a substantial improvement in fabrication resolution for bioinks with an HCD. Fifty-micrometer fabrication resolution was achieved for a bioink with 0.1 billion per milliliter cell density. To showcase the potential application in tissue/organ 3D bioprinting, HCD thick tissues with fine vascular networks were fabricated. The tissues were viable in a perfusion culture system, with endothelialization and angiogenesis observed after 14 days of culture.
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Affiliation(s)
- Shangting You
- Department of NanoEngineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Yi Xiang
- Department of NanoEngineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Henry H. Hwang
- Department of NanoEngineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - David B. Berry
- Department of NanoEngineering, University of California, San Diego, La Jolla, CA 92093, USA
- Department of Orthopedic Surgery, University of California, San Diego, La Jolla, CA 92093, USA
| | - Wisarut Kiratitanaporn
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Jiaao Guan
- Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Emmie Yao
- Department of NanoEngineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Min Tang
- Department of NanoEngineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Zheng Zhong
- Department of NanoEngineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Xinyue Ma
- School of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Daniel Wangpraseurt
- Department of NanoEngineering, University of California, San Diego, La Jolla, CA 92093, USA
- Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA 92093, USA
| | - Yazhi Sun
- Department of NanoEngineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Ting-yu Lu
- Materials Science and Engineering Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Shaochen Chen
- Department of NanoEngineering, University of California, San Diego, La Jolla, CA 92093, USA
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
- Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, CA 92093, USA
- Materials Science and Engineering Program, University of California, San Diego, La Jolla, CA 92093, USA
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24
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Wang S, Saeidi T, Lilge L, Betz V. Integrating clinical access limitations into iPDT treatment planning with PDT-SPACE. BIOMEDICAL OPTICS EXPRESS 2023; 14:714-738. [PMID: 36874501 PMCID: PMC9979674 DOI: 10.1364/boe.478217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 01/03/2023] [Accepted: 01/03/2023] [Indexed: 06/18/2023]
Abstract
PDT-SPACE is an open-source software tool that automates interstitial photodynamic therapy treatment planning by providing patient-specific placement of light sources to destroy a tumor while minimizing healthy tissue damage. This work extends PDT-SPACE in two ways. The first enhancement allows specification of clinical access constraints on light source insertion to avoid penetrating critical structures and to minimize surgical complexity. Constraining fiber access to a single burr hole of adequate size increases healthy tissue damage by 10%. The second enhancement generates an initial placement of light sources as a starting point for refinement, rather than requiring entry of a starting solution by the clinician. This feature improves productivity and also leads to solutions with 4.5% less healthy tissue damage. The two features are used in concert to perform simulations of various surgery options of virtual glioblastoma multiforme brain tumors.
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Affiliation(s)
- Shuran Wang
- Edward S. Rogers Sr. Department of Electrical and Computer Engineering, University of Toronto, 10 King’s College Rd, Toronto, ON M5S3G8, Canada
| | - Tina Saeidi
- Department of Medical Biophysics, University of Toronto, Princess Margaret Cancer Centre, University Health Network, 101 College Street, Toronto, ON M5G1L7, Canada
| | - Lothar Lilge
- Department of Medical Biophysics, University of Toronto, Princess Margaret Cancer Centre, University Health Network, 101 College Street, Toronto, ON M5G1L7, Canada
| | - Vaughn Betz
- Edward S. Rogers Sr. Department of Electrical and Computer Engineering, University of Toronto, 10 King’s College Rd, Toronto, ON M5S3G8, Canada
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25
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Parilov E, Beeson K, Potasek M, Zhu T, Sun H, Sourvanos D. A Monte Carlo simulation for Moving Light Source in Intracavity PDT. PROCEEDINGS OF SPIE--THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING 2023; 12359:1235903. [PMID: 37206985 PMCID: PMC10194003 DOI: 10.1117/12.2649538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
We developed a simulation method for modeling the light fluence delivery in intracavity Photodynamic Therapy (icav-PDT) for pleural lung cancer using a moving light source. Due to the large surface area of the pleural lung cavity, the light source needs to be moved to deliver a uniform dose around the entire cavity. While multiple fixed detectors are used for dosimetry at a few locations, an accurate simulation of light fluence and fluence rate is still needed for the rest of the cavity. We extended an existing Monte Carlo (MC) based light propagation solver to support moving light sources by densely sampling the continuous light source trajectory and assigning the proper number of photon packages launched along the way. The performance of Simphotek GPU CUDA-based implementation of the method - PEDSy-MC - has been demonstrated on a life-size lung-shaped phantom, custom printed for testing icav-PDT navigation system at the Perlman School of Medicine (PSM) - calculations completed under a minute (for some cases) and within minutes have been achieved. We demonstrate results within a 5% error of the analytic solution for multiple detectors in the phantom. PEDSy-MC is accompanied by a dose-cavity visualization tool that allows real-time inspection of dose values of the treated cavity in 2D and 3D, which will be expanded to ongoing clinical trials at PSM. PSM has developed a technology to measure 8-detectors in a pleural cavity phantom using Photofrin-mediated PDT that has been used during validation.
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Affiliation(s)
| | - Karl Beeson
- Simphotek, Inc., 211 Warren St., Newark, NJ 07103
| | - Mary Potasek
- Simphotek, Inc., 211 Warren St., Newark, NJ 07103
| | - Timothy Zhu
- Perlman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Hongjing Sun
- Perlman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Dennis Sourvanos
- Department of Periodontics, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
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26
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Lange F, Verma V, Harvey-Jones K, Mitra S, Tachtsidis I. Neonatal Brain Temperature Monitoring Based on Broadband Near-Infrared Spectroscopy. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1438:167-172. [PMID: 37845456 DOI: 10.1007/978-3-031-42003-0_26] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2023]
Abstract
We present here the initial development of a novel algorithm based on broadband near-infrared spectroscopy (bNIRS) data to estimate the changes in brain temperature (BT) in neonates. We first explored the validity of the methodology on a simple numerical phantom and reported good agreements between the theoretical and retrieved values of BT and hemodynamic parameters changes, which are the parameters usually targeted by bNIRS. However, we noted an underestimation of the absolute values of temperature and haemoglobins' concentration changes when large variations of tissue saturation were induced, probably due to a crosstalk between the species in this specific case. We then tested this methodology on data acquired on 2 piglets during a protocol that induces seizures. We showed that despite a decrease in rectal temperature (RT) over time (-0.1048 °C 1.5 h after seizure induction, 95% CI: -0.1035 to -0.1061 °C), BT was raising (0.3122 °C 1.5 h after seizure induction, 95% CI: 0.3207 to 0.3237 °C). We also noted that the piglet displaying the largest decrease in RT also displays the highest increase in BT, which could be a marker of the severity of the seizure induced brain injury. These initial results are encouraging and show that having access to the changes in BT non-invasively could help to better understand the impact of BT on injury severity and to improve the current cooling methodologies in the neonatal neurocritical care following neonatal encephalopathy.
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Affiliation(s)
- F Lange
- Department of Medical Physics and Biomedical Engineering, University College London, London, UK.
| | - V Verma
- Institute for Women's Health, University College London, London, UK
| | - K Harvey-Jones
- Institute for Women's Health, University College London, London, UK
| | - S Mitra
- Institute for Women's Health, University College London, London, UK
| | - I Tachtsidis
- Department of Medical Physics and Biomedical Engineering, University College London, London, UK
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27
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Vella D, Lukač M, Jernejčič U, Lukač N, Klaneček Ž, Milanič M, Jezeršek M. Measurements of hair temperature avalanche effect with alexandrite and Nd:YAG hair removal lasers. Lasers Surg Med 2023; 55:89-98. [PMID: 36490355 PMCID: PMC10107531 DOI: 10.1002/lsm.23622] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 10/17/2022] [Accepted: 11/28/2022] [Indexed: 12/14/2022]
Abstract
BACKGROUND AND OBJECTIVES In this study, we investigate the photothermal response of human hair using a pulsed laser source employed in the hair removal treatment. The purpose is to understand the dynamics behind the most common clinical practice to better define the salient features that may contribute to the efficiency of the process. STUDY DESIGN/MATERIALS AND METHODS Temperature changes of hair samples (dark brown color) from a human scalp (skin type Fitpatrick II) were measured by a thermal camera following irradiation with single and multiple neodymium: yttrium-aluminum-garnet (Nd:YAG) (1064 nm) and alexandrite (755 nm) laser pulses. Particularly, the hair was treated with an individual laser pulse of a sufficiently high fluence, or with a series of lower fluence laser pulses. We investigated the temperature increase in a broad range of fluence and number of pulses. From the data analysis we extrapolated important parameters such as thermal gain and threshold fluence that can be used for determining optimal parameters for the hair removal procedure. Our experimental investigations and hypothesis were supported by a numerical simulation of the light-matter interaction in a skin-hair model, and by optical transmittance measurements of the irradiated hair. RESULTS An enhancement of the temperature response of the irradiated hair, that deviates from the linear behavior, is observed when hair is subjected to an individual laser pulse of a sufficiently high fluence or to a series of lower fluence laser pulses. Here, we defined the nonlinear and rapid temperature built-up as an avalanche effect. We estimated the threshold fluence at which this process takes place to be at 10 and 2.5 J/cm2 for 1064 and 755 nm laser wavelengths, respectively. The thermal gain expressed by the degree of the deviation from the linear behavior can be higher than 2 when low laser fluence and multiple laser pulses are applied (n = 50). The comparison of the calculated gain for the two different laser wavelengths and the number of pulses reveals a much higher efficiency when low fluence and multiple pulses are delivered. The avalanche effect manifests when the hair temperature exceeds 45°C. The enhanced temperature increase during the subsequent delivery of laser pulses could be ascribed to the temperature-induced changes in the hair's structural properties. Simulations of the hair temperature under Nd:YAG and alexandrite irradiation indicate that the avalanche phenomenon observed in the hair suspended in air may apply also to the hair located within the skin matrix. Namely, for the same fluence, similar temperature increase was obtained also for the hair located within the skin. CONCLUSION The observed "avalanche" effect may contribute to the reported clinical efficacy of laser hair removal and may at least partially explain the observed efficacy of the brushing hair removal procedures where laser fluence is usually low. The repeated irradiation during the brushing procedure may lead to an avalanche-like gradual increase of the hair's thermal response resulting in sufficiently high final hair temperatures as required for effective hair reduction.
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Affiliation(s)
- Daniele Vella
- Laboratory for Laser Techniques, Faculty of Mechanical Engineering, University of Ljubljana, Ljubljana, Slovenia
| | - Matjaž Lukač
- Department of Complex Matter, Institut Jozef Stefan, Ljubljana, Slovenia
| | | | - Nejc Lukač
- Laboratory for Laser Techniques, Faculty of Mechanical Engineering, University of Ljubljana, Ljubljana, Slovenia
| | - Žan Klaneček
- Department of Physics, Faculty of Mathematics and Physics, University of Ljubljana, Ljubljana, Slovenia
| | - Matija Milanič
- Department of Complex Matter, Institut Jozef Stefan, Ljubljana, Slovenia.,Department of Physics, Faculty of Mathematics and Physics, University of Ljubljana, Ljubljana, Slovenia
| | - Matija Jezeršek
- Laboratory for Laser Techniques, Faculty of Mechanical Engineering, University of Ljubljana, Ljubljana, Slovenia
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28
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Sassaroli A, Tommasi F, Cavalieri S, Martelli F. Fluence rate directly derived from photon pathlengths: a tool for Monte Carlo simulations in biomedical optics. BIOMEDICAL OPTICS EXPRESS 2023; 14:148-162. [PMID: 36698672 PMCID: PMC9842009 DOI: 10.1364/boe.477339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 11/25/2022] [Accepted: 11/28/2022] [Indexed: 06/17/2023]
Abstract
In biomedical optics, the mean fluence rate of photons, assessed in a sub-volume of a propagating medium, is classically obtained in Monte Carlo simulations by taking into account the power deposited by the absorbed photons in the sub-volume. In the present contribution, we propose and analytically demonstrate an alternative method based on the assessment of the mean pathlength traveled by all the photons inside the sub-volume. Few practical examples of its applications are given. This method has the advantage of improving, in many cases, the statistics and the convergence of the Monte Carlo simulations. Further, it also works when the absorption coefficient is nil and for a non-constant spatial distribution of the absorption coefficient inside the sub-volume. The proposed approach is a re-visitation of a well-known method applied in radiation and nuclear physics in the context of radiative transfer, where it can be derived in a more natural manner.
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Affiliation(s)
- Angelo Sassaroli
- Department of Biomedical Engineering, Tufts University, 4 Colby Street, Medford, MA 02155, USA
| | - Federico Tommasi
- Dipartimento di Fisica e Astronomia dell’Università degli Studi di Firenze, via Giovanni Sansone 1, 50019 Sesto Fiorentino, Italy
| | - Stefano Cavalieri
- Dipartimento di Fisica e Astronomia dell’Università degli Studi di Firenze, via Giovanni Sansone 1, 50019 Sesto Fiorentino, Italy
| | - Fabrizio Martelli
- Dipartimento di Fisica e Astronomia dell’Università degli Studi di Firenze, via Giovanni Sansone 1, 50019 Sesto Fiorentino, Italy
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29
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Efficient computation of the steady-state and time-domain solutions of the photon diffusion equation in layered turbid media. Sci Rep 2022; 12:18979. [PMID: 36347893 PMCID: PMC9643457 DOI: 10.1038/s41598-022-22649-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 10/18/2022] [Indexed: 11/09/2022] Open
Abstract
Accurate and efficient forward models of photon migration in heterogeneous geometries are important for many applications of light in medicine because many biological tissues exhibit a layered structure of independent optical properties and thickness. However, closed form analytical solutions are not readily available for layered tissue-models, and often are modeled using computationally expensive numerical techniques or theoretical approximations that limit accuracy and real-time analysis. Here, we develop an open-source accurate, efficient, and stable numerical routine to solve the diffusion equation in the steady-state and time-domain for a layered cylinder tissue model with an arbitrary number of layers and specified thickness and optical coefficients. We show that the steady-state ([Formula: see text] ms) and time-domain ([Formula: see text] ms) fluence (for an 8-layer medium) can be calculated with absolute numerical errors approaching machine precision. The numerical implementation increased computation speed by 3 to 4 orders of magnitude compared to previously reported theoretical solutions in layered media. We verify our solutions asymptotically to homogeneous tissue geometries using closed form analytical solutions to assess convergence and numerical accuracy. Approximate solutions to compute the reflected intensity are presented which can decrease the computation time by an additional 2-3 orders of magnitude. We also compare our solutions for 2, 3, and 5 layered media to gold-standard Monte Carlo simulations in layered tissue models of high interest in biomedical optics (e.g. skin/fat/muscle and brain). The presented routine could enable more robust real-time data analysis tools in heterogeneous tissues that are important in many clinical applications such as functional brain imaging and diffuse optical spectroscopy.
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30
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Muller JW, Arabul MÜ, Schwab HM, Rutten MCM, van Sambeek MRHM, Wu M, Lopata RGP. Modeling toolchain for realistic simulation of photoacoustic data acquisition. JOURNAL OF BIOMEDICAL OPTICS 2022; 27:096005. [PMID: 36104838 PMCID: PMC9470848 DOI: 10.1117/1.jbo.27.9.096005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 08/31/2022] [Indexed: 06/15/2023]
Abstract
SIGNIFICANCE Physics-based simulations of photoacoustic (PA) signals are used to validate new methods, to characterize PA setups and to generate training datasets for machine learning. However, a thoroughly validated PA simulation toolchain that can simulate realistic images is still lacking. AIM A quantitative toolchain was developed to model PA image acquisition in complex tissues, by simulating both the optical fluence and the acoustic wave propagation. APPROACH Sampling techniques were developed to decrease artifacts in acoustic simulations. The performance of the simulations was analyzed by measuring the point spread function (PSF) and using a rotatable three-channel phantom, filled with cholesterol, a human carotid plaque sample, and porcine blood. Ex vivo human plaque samples were simulated to validate the methods in more complex tissues. RESULTS The sampling techniques could enhance the quality of the simulated PA images effectively. The resolution and intensity of the PSF in the turbid medium matched the experimental data well. Overall, the appearance, signal-to-noise ratio and speckle of the images could be simulated accurately. CONCLUSIONS A PA toolchain was developed and validated, and the results indicate a great potential of PA simulations in more complex and heterogeneous media.
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Affiliation(s)
- Jan-Willem Muller
- Eindhoven University of Technology, Photoacoustics and Ultrasound Laboratory Eindhoven, Department of Biomedical Engineering, Eindhoven, The Netherlands
- Catharina Hospital, Department of Vascular Surgery, Eindhoven, The Netherlands
| | - Mustafa Ü. Arabul
- Eindhoven University of Technology, Photoacoustics and Ultrasound Laboratory Eindhoven, Department of Biomedical Engineering, Eindhoven, The Netherlands
| | - Hans-Martin Schwab
- Eindhoven University of Technology, Photoacoustics and Ultrasound Laboratory Eindhoven, Department of Biomedical Engineering, Eindhoven, The Netherlands
| | - Marcel C. M. Rutten
- Cardiovascular Biomechanics Group, Department of Biomedical Engineering, Eindhoven, The Netherlands
| | - Marc R. H. M. van Sambeek
- Eindhoven University of Technology, Photoacoustics and Ultrasound Laboratory Eindhoven, Department of Biomedical Engineering, Eindhoven, The Netherlands
- Catharina Hospital, Department of Vascular Surgery, Eindhoven, The Netherlands
| | - Min Wu
- Eindhoven University of Technology, Photoacoustics and Ultrasound Laboratory Eindhoven, Department of Biomedical Engineering, Eindhoven, The Netherlands
| | - Richard G. P. Lopata
- Eindhoven University of Technology, Photoacoustics and Ultrasound Laboratory Eindhoven, Department of Biomedical Engineering, Eindhoven, The Netherlands
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31
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Ayaz H, Baker WB, Blaney G, Boas DA, Bortfeld H, Brady K, Brake J, Brigadoi S, Buckley EM, Carp SA, Cooper RJ, Cowdrick KR, Culver JP, Dan I, Dehghani H, Devor A, Durduran T, Eggebrecht AT, Emberson LL, Fang Q, Fantini S, Franceschini MA, Fischer JB, Gervain J, Hirsch J, Hong KS, Horstmeyer R, Kainerstorfer JM, Ko TS, Licht DJ, Liebert A, Luke R, Lynch JM, Mesquida J, Mesquita RC, Naseer N, Novi SL, Orihuela-Espina F, O’Sullivan TD, Peterka DS, Pifferi A, Pollonini L, Sassaroli A, Sato JR, Scholkmann F, Spinelli L, Srinivasan VJ, St. Lawrence K, Tachtsidis I, Tong Y, Torricelli A, Urner T, Wabnitz H, Wolf M, Wolf U, Xu S, Yang C, Yodh AG, Yücel MA, Zhou W. Optical imaging and spectroscopy for the study of the human brain: status report. NEUROPHOTONICS 2022; 9:S24001. [PMID: 36052058 PMCID: PMC9424749 DOI: 10.1117/1.nph.9.s2.s24001] [Citation(s) in RCA: 55] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
This report is the second part of a comprehensive two-part series aimed at reviewing an extensive and diverse toolkit of novel methods to explore brain health and function. While the first report focused on neurophotonic tools mostly applicable to animal studies, here, we highlight optical spectroscopy and imaging methods relevant to noninvasive human brain studies. We outline current state-of-the-art technologies and software advances, explore the most recent impact of these technologies on neuroscience and clinical applications, identify the areas where innovation is needed, and provide an outlook for the future directions.
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Affiliation(s)
- Hasan Ayaz
- Drexel University, School of Biomedical Engineering, Science, and Health Systems, Philadelphia, Pennsylvania, United States
- Drexel University, College of Arts and Sciences, Department of Psychological and Brain Sciences, Philadelphia, Pennsylvania, United States
| | - Wesley B. Baker
- Children’s Hospital of Philadelphia, Division of Neurology, Philadelphia, Pennsylvania, United States
- Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Giles Blaney
- Tufts University, Department of Biomedical Engineering, Medford, Massachusetts, United States
| | - David A. Boas
- Boston University Neurophotonics Center, Boston, Massachusetts, United States
- Boston University, College of Engineering, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - Heather Bortfeld
- University of California, Merced, Departments of Psychological Sciences and Cognitive and Information Sciences, Merced, California, United States
| | - Kenneth Brady
- Lurie Children’s Hospital, Northwestern University Feinberg School of Medicine, Department of Anesthesiology, Chicago, Illinois, United States
| | - Joshua Brake
- Harvey Mudd College, Department of Engineering, Claremont, California, United States
| | - Sabrina Brigadoi
- University of Padua, Department of Developmental and Social Psychology, Padua, Italy
| | - Erin M. Buckley
- Georgia Institute of Technology, Wallace H. Coulter Department of Biomedical Engineering, Atlanta, Georgia, United States
- Emory University School of Medicine, Department of Pediatrics, Atlanta, Georgia, United States
| | - Stefan A. Carp
- Massachusetts General Hospital, Harvard Medical School, Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, Massachusetts, United States
| | - Robert J. Cooper
- University College London, Department of Medical Physics and Bioengineering, DOT-HUB, London, United Kingdom
| | - Kyle R. Cowdrick
- Georgia Institute of Technology, Wallace H. Coulter Department of Biomedical Engineering, Atlanta, Georgia, United States
| | - Joseph P. Culver
- Washington University School of Medicine, Department of Radiology, St. Louis, Missouri, United States
| | - Ippeita Dan
- Chuo University, Faculty of Science and Engineering, Tokyo, Japan
| | - Hamid Dehghani
- University of Birmingham, School of Computer Science, Birmingham, United Kingdom
| | - Anna Devor
- Boston University, College of Engineering, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - Turgut Durduran
- ICFO – The Institute of Photonic Sciences, The Barcelona Institute of Science and Technology, Castelldefels, Barcelona, Spain
- Institució Catalana de Recerca I Estudis Avançats (ICREA), Barcelona, Spain
| | - Adam T. Eggebrecht
- Washington University in St. Louis, Mallinckrodt Institute of Radiology, St. Louis, Missouri, United States
| | - Lauren L. Emberson
- University of British Columbia, Department of Psychology, Vancouver, British Columbia, Canada
| | - Qianqian Fang
- Northeastern University, Department of Bioengineering, Boston, Massachusetts, United States
| | - Sergio Fantini
- Tufts University, Department of Biomedical Engineering, Medford, Massachusetts, United States
| | - Maria Angela Franceschini
- Massachusetts General Hospital, Harvard Medical School, Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, Massachusetts, United States
| | - Jonas B. Fischer
- ICFO – The Institute of Photonic Sciences, The Barcelona Institute of Science and Technology, Castelldefels, Barcelona, Spain
| | - Judit Gervain
- University of Padua, Department of Developmental and Social Psychology, Padua, Italy
- Université Paris Cité, CNRS, Integrative Neuroscience and Cognition Center, Paris, France
| | - Joy Hirsch
- Yale School of Medicine, Department of Psychiatry, Neuroscience, and Comparative Medicine, New Haven, Connecticut, United States
- University College London, Department of Medical Physics and Biomedical Engineering, London, United Kingdom
| | - Keum-Shik Hong
- Pusan National University, School of Mechanical Engineering, Busan, Republic of Korea
- Qingdao University, School of Automation, Institute for Future, Qingdao, China
| | - Roarke Horstmeyer
- Duke University, Department of Biomedical Engineering, Durham, North Carolina, United States
- Duke University, Department of Electrical and Computer Engineering, Durham, North Carolina, United States
- Duke University, Department of Physics, Durham, North Carolina, United States
| | - Jana M. Kainerstorfer
- Carnegie Mellon University, Department of Biomedical Engineering, Pittsburgh, Pennsylvania, United States
- Carnegie Mellon University, Neuroscience Institute, Pittsburgh, Pennsylvania, United States
| | - Tiffany S. Ko
- Children’s Hospital of Philadelphia, Division of Cardiothoracic Anesthesiology, Philadelphia, Pennsylvania, United States
| | - Daniel J. Licht
- Children’s Hospital of Philadelphia, Division of Neurology, Philadelphia, Pennsylvania, United States
| | - Adam Liebert
- Polish Academy of Sciences, Nalecz Institute of Biocybernetics and Biomedical Engineering, Warsaw, Poland
| | - Robert Luke
- Macquarie University, Department of Linguistics, Sydney, New South Wales, Australia
- Macquarie University Hearing, Australia Hearing Hub, Sydney, New South Wales, Australia
| | - Jennifer M. Lynch
- Children’s Hospital of Philadelphia, Division of Cardiothoracic Anesthesiology, Philadelphia, Pennsylvania, United States
| | - Jaume Mesquida
- Parc Taulí Hospital Universitari, Critical Care Department, Sabadell, Spain
| | - Rickson C. Mesquita
- University of Campinas, Institute of Physics, Campinas, São Paulo, Brazil
- Brazilian Institute of Neuroscience and Neurotechnology, Campinas, São Paulo, Brazil
| | - Noman Naseer
- Air University, Department of Mechatronics and Biomedical Engineering, Islamabad, Pakistan
| | - Sergio L. Novi
- University of Campinas, Institute of Physics, Campinas, São Paulo, Brazil
- Western University, Department of Physiology and Pharmacology, London, Ontario, Canada
| | | | - Thomas D. O’Sullivan
- University of Notre Dame, Department of Electrical Engineering, Notre Dame, Indiana, United States
| | - Darcy S. Peterka
- Columbia University, Zuckerman Mind Brain Behaviour Institute, New York, United States
| | | | - Luca Pollonini
- University of Houston, Department of Engineering Technology, Houston, Texas, United States
| | - Angelo Sassaroli
- Tufts University, Department of Biomedical Engineering, Medford, Massachusetts, United States
| | - João Ricardo Sato
- Federal University of ABC, Center of Mathematics, Computing and Cognition, São Bernardo do Campo, São Paulo, Brazil
| | - Felix Scholkmann
- University of Bern, Institute of Complementary and Integrative Medicine, Bern, Switzerland
- University of Zurich, University Hospital Zurich, Department of Neonatology, Biomedical Optics Research Laboratory, Zürich, Switzerland
| | - Lorenzo Spinelli
- National Research Council (CNR), IFN – Institute for Photonics and Nanotechnologies, Milan, Italy
| | - Vivek J. Srinivasan
- University of California Davis, Department of Biomedical Engineering, Davis, California, United States
- NYU Langone Health, Department of Ophthalmology, New York, New York, United States
- NYU Langone Health, Department of Radiology, New York, New York, United States
| | - Keith St. Lawrence
- Lawson Health Research Institute, Imaging Program, London, Ontario, Canada
- Western University, Department of Medical Biophysics, London, Ontario, Canada
| | - Ilias Tachtsidis
- University College London, Department of Medical Physics and Biomedical Engineering, London, United Kingdom
| | - Yunjie Tong
- Purdue University, Weldon School of Biomedical Engineering, West Lafayette, Indiana, United States
| | - Alessandro Torricelli
- Politecnico di Milano, Dipartimento di Fisica, Milan, Italy
- National Research Council (CNR), IFN – Institute for Photonics and Nanotechnologies, Milan, Italy
| | - Tara Urner
- Georgia Institute of Technology, Wallace H. Coulter Department of Biomedical Engineering, Atlanta, Georgia, United States
| | - Heidrun Wabnitz
- Physikalisch-Technische Bundesanstalt (PTB), Berlin, Germany
| | - Martin Wolf
- University of Zurich, University Hospital Zurich, Department of Neonatology, Biomedical Optics Research Laboratory, Zürich, Switzerland
| | - Ursula Wolf
- University of Bern, Institute of Complementary and Integrative Medicine, Bern, Switzerland
| | - Shiqi Xu
- Duke University, Department of Biomedical Engineering, Durham, North Carolina, United States
| | - Changhuei Yang
- California Institute of Technology, Department of Electrical Engineering, Pasadena, California, United States
| | - Arjun G. Yodh
- University of Pennsylvania, Department of Physics and Astronomy, Philadelphia, Pennsylvania, United States
| | - Meryem A. Yücel
- Boston University Neurophotonics Center, Boston, Massachusetts, United States
- Boston University, College of Engineering, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - Wenjun Zhou
- University of California Davis, Department of Biomedical Engineering, Davis, California, United States
- China Jiliang University, College of Optical and Electronic Technology, Hangzhou, Zhejiang, China
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McMillan L, Bruce GD, Dholakia K. Meshless Monte Carlo radiation transfer method for curved geometries using signed distance functions. JOURNAL OF BIOMEDICAL OPTICS 2022; 27:JBO-210394SSRRR. [PMID: 35927789 PMCID: PMC9350858 DOI: 10.1117/1.jbo.27.8.083003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 07/20/2022] [Indexed: 05/18/2023]
Abstract
SIGNIFICANCE Monte Carlo radiation transfer (MCRT) is the gold standard for modeling light transport in turbid media. Typical MCRT models use voxels or meshes to approximate experimental geometry. A voxel-based geometry does not allow for the precise modeling of smooth curved surfaces, such as may be found in biological systems or food and drink packaging. Mesh-based geometry allows arbitrary complex shapes with smooth curved surfaces to be modeled. However, mesh-based models also suffer from issues such as the computational cost of generating meshes and inaccuracies in how meshes handle reflections and refractions. AIM We present our algorithm, which we term signedMCRT (sMCRT), a geometry-based method that uses signed distance functions (SDF) to represent the geometry of the model. SDFs are capable of modeling smooth curved surfaces precisely while also modeling complex geometries. APPROACH We show that using SDFs to represent the problem's geometry is more precise than voxel and mesh-based methods. RESULTS sMCRT is validated against theoretical expressions, and voxel and mesh-based MCRT codes. We show that sMCRT can precisely model arbitrary complex geometries such as microvascular vessel network using SDFs. In comparison with the current state-of-the-art in MCRT methods specifically for curved surfaces, sMCRT is more precise for cases where the geometry can be defined using combinations of shapes. CONCLUSIONS We believe that SDF-based MCRT models are a complementary method to voxel and mesh models in terms of being able to model complex geometries and accurately treat curved surfaces, with a focus on precise simulation of reflections and refractions. sMCRT is publicly available at https://github.com/lewisfish/signedMCRT.
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Affiliation(s)
- Lewis McMillan
- University of St Andrews, SUPA School of Physics and Astronomy, St Andrews, Scotland
- Address all correspondence to Lewis McMillan,
| | - Graham D. Bruce
- University of St Andrews, SUPA School of Physics and Astronomy, St Andrews, Scotland
| | - Kishan Dholakia
- University of St Andrews, SUPA School of Physics and Astronomy, St Andrews, Scotland
- Yonsei University, College of Science, Department of Physics, Seoul, South Korea
- The University of Adelaide, School of Biological Sciences, Adelaide, South Australia, Australia
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Fu X, Richards JE. Age-related changes in diffuse optical tomography sensitivity profiles from childhood to adulthood. JOURNAL OF BIOMEDICAL OPTICS 2022; 27:083004. [PMID: 35810323 PMCID: PMC9270691 DOI: 10.1117/1.jbo.27.8.083004] [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: 02/27/2022] [Accepted: 06/22/2022] [Indexed: 06/15/2023]
Abstract
SIGNIFICANCE Diffuse optical tomography (DOT) uses near-infrared light spectroscopy to measure changes in cerebral hemoglobin concentration. Anatomical interpretations of the brain location that generates the hemodynamic signal require accurate descriptions of the DOT sensitivity to the underlying cortex. DOT sensitivity profiles are different in infants compared with adults. However, the descriptions of DOT sensitivity profiles from early childhood to adulthood are lacking despite the continuous head and brain development. AIM We aim to investigate age-related differences in DOT sensitivity profiles in individuals aged from 2 to 34 years with narrow age ranges of 0.5 or 1 year. APPROACH We implemented existing photon migration simulation methods and computed source-detector channel DOT sensitivity using age-appropriate, realistic head models. RESULTS DOT sensitivity profiles change systematically as a function of source-detector separation distance for all age groups. Children displayed distinctive DOT sensitivity profiles compared to older individuals, and the differences were enhanced at larger separation distances. CONCLUSIONS The findings have important implications for the design of source-detector placement and image reconstruction. Age-appropriate realistic head models should be used to provide anatomical guidance for standalone DOT data. Using age-inappropriate head models will have more negative impacts on estimation accuracy in younger children.
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Affiliation(s)
- Xiaoxue Fu
- University of South Carolina, Department of Psychology, Columbia, South Carolina, United States
| | - John E. Richards
- University of South Carolina, Department of Psychology, Columbia, South Carolina, United States
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Analysis of Numerical Artifacts Using Tetrahedral Meshes in Low Frequency Numerical Dosimetry. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12136526] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Anatomical realistic voxel models of human beings are commonly used in numerical dosimetry to evaluate the human exposure to low-frequency electromagnetic fields. The downside of these models is that they do not correctly reproduce the boundaries of curved surfaces. The stair-casing approximation errors introduce computational artifacts in the evaluation of the induced electric field and the use of post-processing filtering methods is essential to mitigate these errors. With a suitable exposure scenario, this paper shows that tetrahedral meshes make it possible to remove stair-casing errors. However, using tetrahedral meshes is not a sufficient condition to completely remove artifacts, because the quality of the tetrahedral mesh plays an important role. The analyses carried out show that in real exposure scenarios, other sources of artifacts cause peak values of the induced electric field even with regular meshes. In these cases, the adoption of filtering techniques cannot be avoided.
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Yan S, Jacques SL, Ramella-Roman JC, Fang Q. Graphics-processing-unit-accelerated Monte Carlo simulation of polarized light in complex three-dimensional media. JOURNAL OF BIOMEDICAL OPTICS 2022; 27:JBO-220009SSR. [PMID: 35534924 PMCID: PMC9084406 DOI: 10.1117/1.jbo.27.8.083015] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 04/08/2022] [Indexed: 05/18/2023]
Abstract
SIGNIFICANCE Monte Carlo (MC) methods have been applied for studying interactions between polarized light and biological tissues, but most existing MC codes supporting polarization modeling can only simulate homogeneous or multi-layered domains, resulting in approximations when handling realistic tissue structures. AIM Over the past decade, the speed of MC simulations has seen dramatic improvement with massively parallel computing techniques. Developing hardware-accelerated MC simulation algorithms that can accurately model polarized light inside three-dimensional (3D) heterogeneous tissues can greatly expand the utility of polarization in biophotonics applications. APPROACH Here, we report a highly efficient polarized MC algorithm capable of modeling arbitrarily complex media defined over a voxelated domain. Each voxel of the domain can be associated with spherical scatters of various radii and densities. The Stokes vector of each simulated photon packet is updated through photon propagation, creating spatially resolved polarization measurements over the detectors or domain surface. RESULTS We have implemented this algorithm in our widely disseminated MC simulator, Monte Carlo eXtreme (MCX). It is validated by comparing with a reference central-processing-unit-based simulator in both homogeneous and layered domains, showing excellent agreement and a 931-fold speedup. CONCLUSION The polarization-enabled MCX offers biophotonics community an efficient tool to explore polarized light in bio-tissues, and is freely available at http://mcx.space/.
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Affiliation(s)
- Shijie Yan
- Northeastern University, Department of Electrical and Computer Engineering, Boston, Massachusetts, United States
| | - Steven L. Jacques
- University of Washington, Department of Bioengineering, Seattle, Washington, United States
| | - Jessica C. Ramella-Roman
- Florida International University, Department of Biomedical Engineering, Miami, Florida, United States
| | - Qianqian Fang
- Northeastern University, Department of Bioengineering, Boston, Massachusetts, United States
- Address all correspondence to Qianqian Fang,
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Miura K, Khantachawana A, Tanaka SM. Optical bone densitometry robust to variation of soft tissue using machine learning techniques: validation by Monte Carlo simulation. JOURNAL OF BIOMEDICAL OPTICS 2022; 27:JBO-220023GRR. [PMID: 35585663 PMCID: PMC9116466 DOI: 10.1117/1.jbo.27.5.056004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Accepted: 04/29/2022] [Indexed: 06/15/2023]
Abstract
SIGNIFICANCE To achieve early detection of osteoporosis, a simple bone densitometry method using optics was proposed. However, individual differences in soft tissue structure and optical properties can cause errors in quantitative bone densitometry. Therefore, developing optical bone densitometry that is robust to soft tissue variations is important for the early detection of osteoporosis. AIM The purpose of this study was to develop an optical bone densitometer that is insensitive to soft tissue, using Monte Carlo simulation and machine learning techniques, and to verify its feasibility. APPROACH We propose a method to measure spatially resolved diffuse light from three directions of the biological tissue model and used machine learning techniques to predict bone density from these data. The three directions are backward, forward, and lateral to the direction of ballistic light irradiation. The method was validated using Monte Carlo simulations using synthetic biological tissue models with 1211 different random structural and optical properties. RESULTS The results were computed after a 10-fold cross-validation. From the simulated optical data, the machine learning model predicted bone density with a coefficient of determination of 0.760. CONCLUSIONS The optical bone densitometry method proposed in this study was found to be robust against individual differences in soft tissue.
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Affiliation(s)
- Kaname Miura
- Kanazawa University, Graduate School of Natural Science and Technology, Division of Mechanical Science and Engineering, Kanazawa, Japan
- King Mongkut’s University of Technology Thonburi, Faculty of Engineering, Biological Engineering Program, Bangkok, Thailand
| | - Anak Khantachawana
- King Mongkut’s University of Technology Thonburi, Department of Mechanical Engineering, Faculty of Engineering, Bangkok, Thailand
| | - Shigeo M. Tanaka
- Kanazawa University, Institute of Science and Engineering, Faculty of Frontier Engineering, Kanazawa, Japan
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Blaney G, Bottoni M, Sassaroli A, Fernandez C, Fantini S. Broadband diffuse optical spectroscopy of two-layered scattering media containing oxyhemoglobin, deoxyhemoglobin, water, and lipids. JOURNAL OF INNOVATIVE OPTICAL HEALTH SCIENCES 2022; 15:2250020. [PMID: 35720681 PMCID: PMC9203000 DOI: 10.1142/s1793545822500201] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
We investigated the relationship between chromophore concentrations in two-layered scattering media and the apparent chromophore concentrations measured with broadband optical spectroscopy in conjunction with commonly used homogeneous medium inverse models. We used diffusion theory togenerate optical data from a two-layered distribution of relevant tissue absorbers, namely, oxyhemoglobin, deoxyhemoglobin, water, and lipids, with a top-layer thickness in the range 1-15 mm. The generated data consisted of broadband continuous-wave (CW) diffuse reflectance in the wavelength range 650-1024 nm, and frequency-domain (FD) diffuse reflectance at 690 and 830 nm; two source-detector distances of 25 and 35 mm were used to simulate a dual-slope technique. The data were inverted using diffusion theory for a semi-infinite homogeneous medium to generate reduced scattering coefficients at 690 and 830 nm (from FD data) and effective absorption spectra in the range 650-1024 nm (from CW data). The absorption spectra were then converted into effective total concentration and oxygen saturation of hemoglobin, as well as water and lipid concentrations. For absolute values, it was found that the effective hemoglobin parameters are typically representative of the bottom layer, whereas water and lipid represent some average of the respective concentrations in the two layers. For concentration changes, lipid showed a significant cross-talk with other absorber concentrations, thus indicating that lipid dynamics obtained in these conditions may not be reliable. These systematic simulations of broadband spectroscopy of two-layered media provide guidance on how to interpret effective optical properties measured with similar instrumental setups under the assumption of medium homogeneity.
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Affiliation(s)
- Giles Blaney
- Department of Biomedical Engineering, Tufts University 4 Colby St, Medford, MA 02155, USA
| | - Martina Bottoni
- Department of Biomedical Engineering, Tufts University 4 Colby St, Medford, MA 02155, USA
- Department of Biomedical Engineering, Politecnico di Torino 24 Corso Duca degli Abruzzi, Torino, TO 10129, Italy
| | - Angelo Sassaroli
- Department of Biomedical Engineering, Tufts University 4 Colby St, Medford, MA 02155, USA
| | - Cristianne Fernandez
- Department of Biomedical Engineering, Tufts University 4 Colby St, Medford, MA 02155, USA
| | - Sergio Fantini
- Department of Biomedical Engineering, Tufts University 4 Colby St, Medford, MA 02155, USA
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Fine J, McShane MJ, Coté GL. Monte Carlo method for assessment of a multimodal insertable biosensor. JOURNAL OF BIOMEDICAL OPTICS 2022; 27:JBO-210299SSRR. [PMID: 35505461 PMCID: PMC9064117 DOI: 10.1117/1.jbo.27.8.083017] [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: 09/28/2021] [Accepted: 04/12/2022] [Indexed: 05/25/2023]
Abstract
SIGNIFICANCE Continuous glucose monitors (CGMs) are increasingly utilized as a way to provide healthcare to the over 10% of Americans that have diabetes. Fully insertable and optically transduced biosensors are poised to further improve CGMs by extending the device lifetime and reducing cost. However, optical modeling of light propagation in tissue is necessary to ascertain device performance. AIM Monte Carlo modeling of photon transport through tissue was used to assess the luminescent output of a fully insertable glucose biosensor that uses a multimodal Förster resonance energy transfer competitive binding assay and a phosphorescence lifetime decay enzymatic assay. APPROACH A Monte Carlo simulation framework of biosensor luminescence and tissue autofluorescence was built using MCmatlab. Simulations were first validated against previous research and then applied to predict the response of a biosensor in development. RESULTS Our results suggest that a diode within the safety standards for light illumination on the skin, with far-red excitation, allows the luminescent biosensor to yield emission strong enough to be detectable by a common photodiode. CONCLUSIONS The computational model showed that the expected fluorescent power output of a near-infrared light actuated barcode was five orders of magnitude greater than a visible spectrum excited counterpart biosensor.
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Affiliation(s)
- Jesse Fine
- Texas A&M University, Department of Biomedical Engineering, College Station, Texas, United States
| | - Michael J. McShane
- Texas A&M University, Department of Biomedical Engineering, College Station, Texas, United States
- Texas A&M University, Department of Materials Science and Engineering, College Station, Texas, United States
- Texas A&M University, Center for Remote Health Technologies and Systems, Texas A&M Engineering Experiment Station, College Station, Texas, United States
| | - Gerard L. Coté
- Texas A&M University, Department of Biomedical Engineering, College Station, Texas, United States
- Texas A&M University, Center for Remote Health Technologies and Systems, Texas A&M Engineering Experiment Station, College Station, Texas, United States
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Sassaroli A, Tommasi F, Cavalieri S, Fini L, Liemert A, Kienle A, Binzoni T, Martelli F. Two-step verification method for Monte Carlo codes in biomedical optics applications. JOURNAL OF BIOMEDICAL OPTICS 2022; 27:JBO-210404GRR. [PMID: 35445592 PMCID: PMC9020254 DOI: 10.1117/1.jbo.27.8.083018] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Accepted: 03/21/2022] [Indexed: 06/14/2023]
Abstract
SIGNIFICANCE Code verification is an unavoidable step prior to using a Monte Carlo (MC) code. Indeed, in biomedical optics, a widespread verification procedure for MC codes is still missing. Analytical benchmarks that can be easily used for the verification of different MC routines offer an important resource. AIM We aim to provide a two-step verification procedure for MC codes enabling the two main tasks of an MC simulator: (1) the generation of photons' trajectories and (2) the intersections of trajectories with boundaries separating the regions with different optical properties. The proposed method is purely based on elementary analytical benchmarks, therefore, the correctness of an MC code can be assessed with a one-sample t-test. APPROACH The two-step verification is based on the following two analytical benchmarks: (1) the exact analytical formulas for the statistical moments of the spatial coordinates where the scattering events occur in an infinite medium and (2) the exact invariant solutions of the radiative transfer equation for radiance, fluence rate, and mean path length in media subjected to a Lambertian illumination. RESULTS We carried out a wide set of comparisons between MC results and the two analytical benchmarks for a wide range of optical properties (from non-scattering to highly scattering media, with different types of scattering functions) in an infinite non-absorbing medium (step 1) and in a non-absorbing slab (step 2). The deviations between MC results and exact analytical values are usually within two standard errors (i.e., t-tests not rejected at a 5% level of significance). The comparisons show that the accuracy of the verification increases with the number of simulated trajectories so that, in principle, an arbitrary accuracy can be obtained. CONCLUSIONS Given the simplicity of the verification method proposed, we envision that it can be widely used in the field of biomedical optics.
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Affiliation(s)
- Angelo Sassaroli
- Tufts University, Department of Biomedical Engineering, Medford, Massachusetts, United States
| | - Federico Tommasi
- Dipartimento di Fisica e Astronomia dell’Università degli Studi di Firenze, Sesto Fiorentino, Italy
| | - Stefano Cavalieri
- Dipartimento di Fisica e Astronomia dell’Università degli Studi di Firenze, Sesto Fiorentino, Italy
| | - Lorenzo Fini
- Dipartimento di Fisica e Astronomia dell’Università degli Studi di Firenze, Sesto Fiorentino, Italy
| | - André Liemert
- Institut für Lasertechnologien in der Medizin und Meßtechnik an der Universität Ulm (ILM), Ulm, Germany
| | - Alwin Kienle
- Institut für Lasertechnologien in der Medizin und Meßtechnik an der Universität Ulm (ILM), Ulm, Germany
| | - Tiziano Binzoni
- University of Geneva, Department of Basic Neurosciences, Geneva, Switzerland
- University Hospital, Department of Radiology and Medical Informatics, Geneva, Switzerland
| | - Fabrizio Martelli
- Dipartimento di Fisica e Astronomia dell’Università degli Studi di Firenze, Sesto Fiorentino, Italy
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Bürmen M, Pernuš F, Naglič P. MCDataset: a public reference dataset of Monte Carlo simulated quantities for multilayered and voxelated tissues computed by massively parallel PyXOpto Python package. JOURNAL OF BIOMEDICAL OPTICS 2022; 27:JBO-210365SSRRR. [PMID: 35437973 PMCID: PMC9016074 DOI: 10.1117/1.jbo.27.8.083012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 03/18/2022] [Indexed: 05/16/2023]
Abstract
SIGNIFICANCE Current open-source Monte Carlo (MC) method implementations for light propagation modeling are many times tedious to build and require third-party licensed software that can often discourage prospective researchers in the biomedical optics community from fully utilizing the light propagation tools. Furthermore, the same drawback also limits rigorous cross-validation of physical quantities estimated by various MC codes. AIM Proposal of an open-source tool for light propagation modeling and an easily accessible dataset to encourage fruitful communications amongst researchers and pave the way to a more consistent comparison between the available implementations of the MC method. APPROACH The PyXOpto implementation of the MC method for multilayered and voxelated tissues based on the Python programming language and PyOpenCL extension enables massively parallel computation on numerous OpenCL-enabled devices. The proposed implementation is used to compute a large dataset of reflectance, transmittance, energy deposition, and sampling volume for various source, detector, and tissue configurations. RESULTS The proposed PyXOpto agrees well with the original MC implementation. However, further validation reveals a noticeable bias introduced by the random number generator used in the original MC implementation. CONCLUSIONS Establishing a common dataset is highly important for the validation of existing and development of MC codes for light propagation in turbid media.
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Affiliation(s)
- Miran Bürmen
- University of Ljubljana, Faculty of Electrical Engineering, Ljubljana, Slovenia
| | - Franjo Pernuš
- University of Ljubljana, Faculty of Electrical Engineering, Ljubljana, Slovenia
- Sensum d.o.o., Ljubljana, Slovenia
| | - Peter Naglič
- University of Ljubljana, Faculty of Electrical Engineering, Ljubljana, Slovenia
- Address all correspondence to Peter Naglič,
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Zhang Y, Fang Q. BlenderPhotonics: an integrated open-source software environment for three-dimensional meshing and photon simulations in complex tissues. JOURNAL OF BIOMEDICAL OPTICS 2022; 27:083014. [PMID: 35429155 PMCID: PMC9010662 DOI: 10.1117/1.jbo.27.8.083014] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 03/23/2022] [Indexed: 06/14/2023]
Abstract
SIGNIFICANCE Rapid advances in biophotonics techniques require quantitative, model-based computational approaches to obtain functional and structural information from increasingly complex and multiscaled anatomies. The lack of efficient tools to accurately model tissue structures and subsequently perform quantitative multiphysics modeling greatly impedes the clinical translation of these modalities. AIM Although the mesh-based Monte Carlo (MMC) method expands our capabilities in simulating complex tissues using tetrahedral meshes, the generation of such domains often requires specialized meshing tools, such as Iso2Mesh. Creating a simplified and intuitive interface for tissue anatomical modeling and optical simulations is essential toward making these advanced modeling techniques broadly accessible to the user community. APPROACH We responded to the above challenge by combining the powerful, open-source three-dimensional (3D) modeling software, Blender, with state-of-the-art 3D mesh generation and MC simulation tools, utilizing the interactive graphical user interface in Blender as the front-end to allow users to create complex tissue mesh models and subsequently launch MMC light simulations. RESULTS Here, we present a tutorial to our Python-based Blender add-on-BlenderPhotonics-to interface with Iso2Mesh and MMC, which allows users to create, configure and refine complex simulation domains and run hardware-accelerated 3D light simulations with only a few clicks. We provide a comprehensive introduction to this tool and walk readers through five examples, ranging from simple shapes to sophisticated realistic tissue models. CONCLUSIONS BlenderPhotonics is user friendly and open source, and it leverages the vastly rich ecosystem of Blender. It wraps advanced modeling capabilities within an easy-to-use and interactive interface. The latest software can be downloaded at http://mcx.space/bp.
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Affiliation(s)
- Yuxuan Zhang
- Northeastern University, Department of Bioengineering, Boston, Massachusetts, United States
| | - Qianqian Fang
- Northeastern University, Department of Bioengineering, Boston, Massachusetts, United States
- Northeastern University, Department of Electrical and Computer Engineering, Boston, Massachusetts, United States
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Nizam NI, Ochoa M, Smith JT, Gao S, Intes X. Monte Carlo-based data generation for efficient deep learning reconstruction of macroscopic diffuse optical tomography and topography applications. JOURNAL OF BIOMEDICAL OPTICS 2022; 27:083016. [PMID: 35484688 PMCID: PMC9048385 DOI: 10.1117/1.jbo.27.8.083016] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 04/12/2022] [Indexed: 06/14/2023]
Abstract
SIGNIFICANCE Deep learning (DL) models are being increasingly developed to map sensor data to the image domain directly. However, DL methodologies are data-driven and require large and diverse data sets to provide robust and accurate image formation performances. For research modalities such as 2D/3D diffuse optical imaging, the lack of large publicly available data sets and the wide variety of instrumentation designs, data types, and applications leads to unique challenges in obtaining well-controlled data sets for training and validation. Meanwhile, great efforts over the last four decades have focused on developing accurate and computationally efficient light propagation models that are flexible enough to simulate a wide variety of experimental conditions. AIM Recent developments in Monte Carlo (MC)-based modeling offer the unique advantage of simulating accurately light propagation spatially, temporally, and over an extensive range of optical parameters, including minimally to highly scattering tissue within a computationally efficient platform. Herein, we demonstrate how such MC platforms, namely "Monte Carlo eXtreme" and "Mesh-based Monte Carlo," can be leveraged to generate large and representative data sets for training the DL model efficiently. APPROACH We propose data generator pipeline strategies using these platforms and demonstrate their potential in fluorescence optical topography, fluorescence optical tomography, and single-pixel diffuse optical tomography. These applications represent a large variety in instrumentation design, sample properties, and contrast function. RESULTS DL models trained using the MC-based in silico datasets, validated further with experimental data not used during training, show accurate and promising results. CONCLUSION Overall, these MC-based data generation pipelines are expected to support the development of DL models for rapid, robust, and user-friendly image formation in a wide variety of applications.
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Affiliation(s)
- Navid Ibtehaj Nizam
- Rensselaer Polytechnic Institute, Department of Biomedical Engineering, Troy, New York, United States
| | - Marien Ochoa
- Rensselaer Polytechnic Institute, Department of Biomedical Engineering, Troy, New York, United States
| | - Jason T. Smith
- Rensselaer Polytechnic Institute, Department of Biomedical Engineering, Troy, New York, United States
| | - Shan Gao
- Rensselaer Polytechnic Institute, Department of Biomedical Engineering, Troy, New York, United States
| | - Xavier Intes
- Rensselaer Polytechnic Institute, Department of Biomedical Engineering, Troy, New York, United States
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Wang S, Dai XY, Ji S, Saeidi T, Schwiegelshohn F, Yassine AA, Lilge L, Betz V. Scalable and accessible personalized photodynamic therapy optimization with FullMonte and PDT-SPACE. JOURNAL OF BIOMEDICAL OPTICS 2022; 27:JBO-210358SSRR. [PMID: 35380030 PMCID: PMC8978262 DOI: 10.1117/1.jbo.27.8.083006] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Accepted: 03/09/2022] [Indexed: 05/08/2023]
Abstract
SIGNIFICANCE Open-source software packages have been extensively used in the past three decades in medical imaging and diagnostics, aiming to study the feasibility of the application ex vivo. Unfortunately, most of the existing open-source tools require some software engineering background to install the prerequisite libraries, choose a suitable computational platform, and combine several software tools to address different applications. AIM To facilitate the use of open-source software in medical applications, enabling computational studies of treatment outcomes prior to the complex in-vivo setting. APPROACH FullMonteWeb, an open-source, user-friendly web-based software with a graphical user interface for interstitial photodynamic therapy (iPDT) modeling, visualization, and optimization, is introduced. The software can perform Monte Carlo simulations of light propagation in biological tissues, along with iPDT plan optimization. FullMonteWeb installs and runs the required software and libraries on Amazon Web Services (AWS), allowing scalable computing without complex set up. RESULTS FullMonteWeb allows simulation of large and small problems on the most appropriate compute hardware, enabling cost improvements of 10 × versus always running on a single platform. Case studies in optical property estimation and diffuser placement optimization highlight FullMonteWeb's versatility. CONCLUSION The FullMonte open source suite enables easier and more cost-effective in-silico studies for iPDT.
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Affiliation(s)
- Shuran Wang
- University of Toronto, Edward S. Rogers Sr. Department of Electrical and Computer Engineering, Toronto, Ontario, Canada
| | - Xiao Ying Dai
- University of Toronto, Edward S. Rogers Sr. Department of Electrical and Computer Engineering, Toronto, Ontario, Canada
| | - Shengxiang Ji
- University of Toronto, Edward S. Rogers Sr. Department of Electrical and Computer Engineering, Toronto, Ontario, Canada
| | - Tina Saeidi
- University of Toronto, Department of Medical Biophysics, Toronto, Ontario, Canada
| | - Fynn Schwiegelshohn
- University of Toronto, Edward S. Rogers Sr. Department of Electrical and Computer Engineering, Toronto, Ontario, Canada
| | - Abdul-Amir Yassine
- University of Toronto, Edward S. Rogers Sr. Department of Electrical and Computer Engineering, Toronto, Ontario, Canada
- Address all correspondence to Abdul-Amir Yassine,
| | - Lothar Lilge
- University of Toronto, Department of Medical Biophysics, Toronto, Ontario, Canada
- University Health Network, Princess Margaret Cancer Centre, Toronto, Ontario, Canada
| | - Vaughn Betz
- University of Toronto, Edward S. Rogers Sr. Department of Electrical and Computer Engineering, Toronto, Ontario, Canada
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Vera DA, García HA, Victoria Waks Serra M, Baez GR, Iriarte DI, Pomarico JA. A Monte Carlo study of near infrared light propagation in the human head with lesions-a time-resolved approach. Biomed Phys Eng Express 2022; 8. [PMID: 35235912 DOI: 10.1088/2057-1976/ac59f3] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 03/01/2022] [Indexed: 11/11/2022]
Abstract
Several clinical conditions leading to traumatic brain injury can cause hematomas or edemas inside the cerebral tissue. If these are not properly treated in time, they are prone to produce long-term neurological disabilities, or even death. Low-cost, portable and easy-to-handle devices are desired for continuous monitoring of these conditions and Near Infrared Spectroscopy (NIRS) techniques represent an appropriate choice. In this work, we use Time-Resolved (TR) Monte Carlo simulations to present a study of NIR light propagation over a digital MRI phantom. Healthy and injured (hematoma/edema) situations are considered. TR Diffuse Reflectance simulations for different lesion volumes and interoptode distances are performed in the frontal area and the left parietal area. Results show that mean partial pathlengths, photon measurement density functions and time dependent contrasts are sensitive to the presence of lesions, allowing their detection mainly for intermediate optodes separations, which proves that these metrics represent robust means of diagnose and monitoring. Conventional Continuous Wave (CW) contrasts are also presented as a particular case of the time dependent ones, but they result less sensitive to the lesions, and have higher associated uncertainties.
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Affiliation(s)
- Demián A Vera
- Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires (CIFICEN, UNCPBA-CICPBA - CONICET) Pinto 399, B7000GHG-Tandil, Buenos Aires, Argentina
| | - Héctor A García
- Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires (CIFICEN, UNCPBA-CICPBA - CONICET) Pinto 399, B7000GHG-Tandil, Buenos Aires, Argentina
| | - Ma Victoria Waks Serra
- Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires (CIFICEN, UNCPBA-CICPBA - CONICET) Pinto 399, B7000GHG-Tandil, Buenos Aires, Argentina
| | - Guido R Baez
- Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires (CIFICEN, UNCPBA-CICPBA - CONICET) Pinto 399, B7000GHG-Tandil, Buenos Aires, Argentina
| | - Daniela I Iriarte
- Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires (CIFICEN, UNCPBA-CICPBA - CONICET) Pinto 399, B7000GHG-Tandil, Buenos Aires, Argentina
| | - Juan A Pomarico
- Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires (CIFICEN, UNCPBA-CICPBA - CONICET) Pinto 399, B7000GHG-Tandil, Buenos Aires, Argentina
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Wu MM, Perdue K, Chan ST, Stephens KA, Deng B, Franceschini MA, Carp SA. Complete head cerebral sensitivity mapping for diffuse correlation spectroscopy using subject-specific magnetic resonance imaging models. BIOMEDICAL OPTICS EXPRESS 2022; 13:1131-1151. [PMID: 35414976 PMCID: PMC8973189 DOI: 10.1364/boe.449046] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 01/16/2022] [Accepted: 01/17/2022] [Indexed: 05/11/2023]
Abstract
We characterize cerebral sensitivity across the entire adult human head for diffuse correlation spectroscopy, an optical technique increasingly used for bedside cerebral perfusion monitoring. Sixteen subject-specific magnetic resonance imaging-derived head models were used to identify high sensitivity regions by running Monte Carlo light propagation simulations at over eight hundred uniformly distributed locations on the head. Significant spatial variations in cerebral sensitivity, consistent across subjects, were found. We also identified correlates of such differences suitable for real-time assessment. These variations can be largely attributed to changes in extracerebral thickness and should be taken into account to optimize probe placement in experimental settings.
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Affiliation(s)
- Melissa M. Wu
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, USA
| | | | - Suk-Tak Chan
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, USA
| | - Kimberly A. Stephens
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, USA
| | - Bin Deng
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, USA
| | | | - Stefan A. Carp
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, USA
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Ewerlöf M, Strömberg T, Larsson M, Salerud EG. Multispectral snapshot imaging of skin microcirculatory hemoglobin oxygen saturation using artificial neural networks trained on in vivo data. JOURNAL OF BIOMEDICAL OPTICS 2022; 27:036004. [PMID: 35340134 PMCID: PMC8957373 DOI: 10.1117/1.jbo.27.3.036004] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Accepted: 03/03/2022] [Indexed: 06/14/2023]
Abstract
SIGNIFICANCE Developing algorithms for estimating blood oxygenation from snapshot multispectral imaging (MSI) data is challenging due to the complexity of sensor characteristics and photon transport modeling in tissue. We circumvent this using a method where artificial neural networks (ANNs) are trained on in vivo MSI data with target values from a point-measuring reference method. AIM To develop and evaluate a methodology where a snapshot filter mosaic camera is utilized for imaging skin hemoglobin oxygen saturation (SO2), using ANNs. APPROACH MSI data were acquired during occlusion provocations. ANNs were trained to estimate SO2 with MSI data as input, targeting data from a validated probe-based reference system. Performance of ANNs with different properties and training data sets was compared. RESULTS The method enables spatially resolved estimation of skin tissue SO2. Results are comparable to those acquired using a Monte-Carlo-based approach when relevant training data are used. CONCLUSIONS Training an ANN on in vivo MSI data covering a wide range of target values acquired during an occlusion protocol enable real-time estimation of SO2 maps. Data from the probe-based reference system can be used as target despite differences in sampling depth and measurement position.
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Affiliation(s)
- Maria Ewerlöf
- Linköping University, Department of Biomedical Engineering, Linköping, Sweden
| | - Tomas Strömberg
- Linköping University, Department of Biomedical Engineering, Linköping, Sweden
| | - Marcus Larsson
- Linköping University, Department of Biomedical Engineering, Linköping, Sweden
| | - E. Göran Salerud
- Linköping University, Department of Biomedical Engineering, Linköping, Sweden
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Cai Z, Machado A, Chowdhury RA, Spilkin A, Vincent T, Aydin Ü, Pellegrino G, Lina JM, Grova C. Diffuse optical reconstructions of functional near infrared spectroscopy data using maximum entropy on the mean. Sci Rep 2022; 12:2316. [PMID: 35145148 PMCID: PMC8831678 DOI: 10.1038/s41598-022-06082-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Accepted: 01/24/2022] [Indexed: 02/07/2023] Open
Abstract
Functional near-infrared spectroscopy (fNIRS) measures the hemoglobin concentration changes associated with neuronal activity. Diffuse optical tomography (DOT) consists of reconstructing the optical density changes measured from scalp channels to the oxy-/deoxy-hemoglobin concentration changes within the cortical regions. In the present study, we adapted a nonlinear source localization method developed and validated in the context of Electro- and Magneto-Encephalography (EEG/MEG): the Maximum Entropy on the Mean (MEM), to solve the inverse problem of DOT reconstruction. We first introduced depth weighting strategy within the MEM framework for DOT reconstruction to avoid biasing the reconstruction results of DOT towards superficial regions. We also proposed a new initialization of the MEM model improving the temporal accuracy of the original MEM framework. To evaluate MEM performance and compare with widely used depth weighted Minimum Norm Estimate (MNE) inverse solution, we applied a realistic simulation scheme which contained 4000 simulations generated by 250 different seeds at different locations and 4 spatial extents ranging from 3 to 40[Formula: see text] along the cortical surface. Our results showed that overall MEM provided more accurate DOT reconstructions than MNE. Moreover, we found that MEM was remained particularly robust in low signal-to-noise ratio (SNR) conditions. The proposed method was further illustrated by comparing to functional Magnetic Resonance Imaging (fMRI) activation maps, on real data involving finger tapping tasks with two different montages. The results showed that MEM provided more accurate HbO and HbR reconstructions in spatial agreement with the main fMRI cluster, when compared to MNE.
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Affiliation(s)
- Zhengchen Cai
- Department of Physics and PERFORM Centre, Concordia University, Montreal, Canada.
| | - Alexis Machado
- Multimodal Functional Imaging Lab, Biomedical Engineering Department, McGill University, Montreal, Canada
| | - Rasheda Arman Chowdhury
- Multimodal Functional Imaging Lab, Biomedical Engineering Department, McGill University, Montreal, Canada
| | - Amanda Spilkin
- Department of Physics and PERFORM Centre, Concordia University, Montreal, Canada
| | - Thomas Vincent
- Department of Physics and PERFORM Centre, Concordia University, Montreal, Canada
- Neurology and Neurosurgery Department, Montreal Neurological Institute, McGill University, Montreal, Canada
- Centre de médecine préventive et d'activité physique, Montréal Heart Institute, Montréal, Canada
| | - Ümit Aydin
- Department of Physics and PERFORM Centre, Concordia University, Montreal, Canada
- MRC Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - Giovanni Pellegrino
- Neurology and Neurosurgery Department, Montreal Neurological Institute, McGill University, Montreal, Canada
| | - Jean-Marc Lina
- École de technologie supérieure de l'Université du Québec, Montréal, Canada
- Centre de Recherches Mathématiques, Université de Montréal, Montréal, Canada
| | - Christophe Grova
- Department of Physics and PERFORM Centre, Concordia University, Montreal, Canada
- Multimodal Functional Imaging Lab, Biomedical Engineering Department, McGill University, Montreal, Canada
- Neurology and Neurosurgery Department, Montreal Neurological Institute, McGill University, Montreal, Canada
- Centre de Recherches Mathématiques, Université de Montréal, Montréal, Canada
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Vanegas M, Mireles M, Fang Q. MOCA: a systematic toolbox for designing and assessing modular functional near-infrared brain imaging probes. NEUROPHOTONICS 2022; 9:017801. [PMID: 36278785 PMCID: PMC8823693 DOI: 10.1117/1.nph.9.1.017801] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 01/11/2022] [Indexed: 05/20/2023]
Abstract
Significance The expansion of functional near-infrared spectroscopy (fNIRS) systems toward broader utilities has led to the emergence of modular fNIRS systems composed of repeating optical source/detector modules. Compared to conventional fNIRS systems, modular fNIRS systems are more compact and flexible, making wearable and long-term monitoring possible. However, the large number of design parameters makes understanding their impact on a probe's performance a daunting task. Aim We aim to create a systematic software platform to facilitate the design, characterization, and comparison of modular fNIRS probes. Approach Our software-modular optode configuration analyzer (MOCA)-implements semi-automatic algorithms that assist in tessellating user-specified regions-of-interest, in interconnecting modules of various shapes, and in quantitatively comparing probe performance using metrics, such as spatial channel distributions and average brain sensitivity of the resulting probes. There is also support for limited parameter sweeping capabilities. Results Through several examples, we show that users can use MOCA to design and optimize modular fNIRS probes, study trade-offs between several module shapes, improve brain sensitivity in probes via module re-orientation, and enhance probe performance via adjusting module spatial layouts. Conclusion Despite its simplicity, our modular probe design platform offers a framework to describe and quantitatively assess probes made by modules, opening a new door for the growing fNIRS user community to approach the challenging problem of module- and probe-parameter selection and fine-tuning.
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Affiliation(s)
- Morris Vanegas
- Northeastern University, Department of Bioengineering, Boston, Massachusetts, United States
| | - Miguel Mireles
- Northeastern University, Department of Bioengineering, Boston, Massachusetts, United States
| | - Qianqian Fang
- Northeastern University, Department of Bioengineering, Boston, Massachusetts, United States
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Fang Q, Yan S. MCX Cloud-a modern, scalable, high-performance and in-browser Monte Carlo simulation platform with cloud computing. JOURNAL OF BIOMEDICAL OPTICS 2022; 27:JBO-210206SSR. [PMID: 34989198 PMCID: PMC8728956 DOI: 10.1117/1.jbo.27.8.083008] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 11/17/2021] [Indexed: 05/06/2023]
Abstract
SIGNIFICANCE Despite the ample progress made toward faster and more accurate Monte Carlo (MC) simulation tools over the past decade, the limited usability and accessibility of these advanced modeling tools remain key barriers to widespread use among the broad user community. AIM An open-source, high-performance, web-based MC simulator that builds upon modern cloud computing architectures is highly desirable to deliver state-of-the-art MC simulations and hardware acceleration to general users without the need for special hardware installation and optimization. APPROACH We have developed a configuration-free, in-browser 3D MC simulation platform-Monte Carlo eXtreme (MCX) Cloud-built upon an array of robust and modern technologies, including a Docker Swarm-based cloud-computing backend and a web-based graphical user interface (GUI) that supports in-browser 3D visualization, asynchronous data communication, and automatic data validation via JavaScript Object Notation (JSON) schemas. RESULTS The front-end of the MCX Cloud platform offers an intuitive simulation design, fast 3D data rendering, and convenient simulation sharing. The Docker Swarm container orchestration backend is highly scalable and can support high-demand GPU MC simulations using MCX over a dynamically expandable virtual cluster. CONCLUSION MCX Cloud makes fast, scalable, and feature-rich MC simulations readily available to all biophotonics researchers without overhead. It is fully open-source and can be freely accessed at http://mcx.space/cloud.
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Affiliation(s)
- Qianqian Fang
- Northeastern University, Department of Bioengineering, Boston, Massachusetts, United States
- Northeastern University, Department of Electrical and Computer Engineering, Boston, Massachusetts, United States
- Address all correspondence to Qianqian Fang,
| | - Shijie Yan
- Northeastern University, Department of Electrical and Computer Engineering, Boston, Massachusetts, United States
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Effects of Different Optical Properties of Head Tissues on Near-Infrared Spectroscopy Using Monte Carlo Simulations. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1395:39-43. [PMID: 36527611 DOI: 10.1007/978-3-031-14190-4_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
In near-infrared spectroscopy (NIRS), it is crucial to have an accurate and realistic model of photon transport in the adult head for obtaining accurate brain oxygenation values. There are several studies on the influence of thickness, the morphology of extracerebral layers, and source-detector distance on the sensitivity of NIRS to the brain. However, the optical properties of the different layers vary between different publications. How is the performance of NIRS affected when the real optical properties differ from the assumed ones?We aim to investigate the influence of variation in scattering and absorption in a five-layered head model (scalp, skull, CSF, grey and white matter). We performed Monte Carlo simulations focusing on a five-layered slab mesh. The range of optical properties is based on a review of the published literature. We assessed the effect on light propagation by measuring the difference in the mean partial path lengths, attenuation, and the number of the detected photons between the different optical properties performing Monte Carlo simulations. For changes in the reduced scattering, we found that the upper layers tend to have a negative impact. In contrast, changes in lower layers tend to impact the brain's influence metrics positively. Furthermore, for small source-detector distances, the relative percentage difference between lower and higher values is greater than larger distances. Conclusions: We conclude that the assumption of different optical properties has a substantial effect on the sensitivity to the brain. This means that it is important to determine the correct optical properties for NIRS measurements in vitro and in vivo.
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