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Crouzet C, Dunn CE, Choi B. Quantifying tissue properties and absolute hemodynamics using coherent spatial imaging. JOURNAL OF BIOMEDICAL OPTICS 2023; 28:127001. [PMID: 38116026 PMCID: PMC10730023 DOI: 10.1117/1.jbo.28.12.127001] [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: 08/01/2023] [Revised: 10/12/2023] [Accepted: 10/30/2023] [Indexed: 12/21/2023]
Abstract
Significance Measuring hemodynamic function is crucial for health assessment. Optical signals provide relative hemoglobin concentration changes, but absolute measurements require costly, bulky technology. Speckleplethysmography (SPG) uses coherent light to detect speckle fluctuations. Combining SPG with multispectral measurements may provide important physiological information on blood flow and absolute hemoglobin concentration. Aim To develop an affordable optical technology to measure tissue absorption, scattering, hemoglobin concentrations, tissue oxygen saturation (StO 2 ), and blood flow. Approach We integrated reflectance spectroscopy and laser speckle imaging to create coherent spatial imaging (CSI). CSI was validated against spatial frequency domain imaging (SFDI) using phantom-based measurements. In vivo arterial and venous occlusion experiments compared CSI with diffuse optical spectroscopy/diffuse correlation spectroscopy (DOS/DCS) measurements. Results CSI and SFDI agreed on tissue absorption and scattering in phantom tests. CSI and DOS/DCS showed similar trends and agreement in arterial occlusion results. During venous occlusion, both uncorrected and corrected blood flow decreased with increasing pressure, with an ∼ 200 % difference in overall blood flow decrease between the methods. CSI and DOS/DCS data showed expected hemoglobin concentrations, StO 2 , and blood flow trends. Conclusions CSI provides affordable and comprehensive hemodynamic information. It can potentially detect dysfunction and improve measurements, such as blood pressure, S p O 2 , and metabolism.
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Affiliation(s)
- Christian Crouzet
- University of California, Irvine, Beckman Laser Institute and Medical Clinic, Irvine, California, United States
| | - Cody E. Dunn
- University of California, Irvine, Beckman Laser Institute and Medical Clinic, Irvine, California, United States
- University of California, Irvine, Department of Biomedical Engineering, Irvine, California, United States
| | - Bernard Choi
- University of California, Irvine, Beckman Laser Institute and Medical Clinic, Irvine, California, United States
- University of California, Irvine, Department of Biomedical Engineering, Irvine, California, United States
- University of California, Irvine, Department of Surgery, Irvine, California, United States
- University of California, Irvine, Edwards Lifesciences Foundation Cardiovascular Innovation Research Center, California, United States
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2
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Hultman M, Larsson M, Strömberg T, Fredriksson I. Speed-resolved perfusion imaging using multi-exposure laser speckle contrast imaging and machine learning. JOURNAL OF BIOMEDICAL OPTICS 2023; 28:036007. [PMID: 36950019 PMCID: PMC10027009 DOI: 10.1117/1.jbo.28.3.036007] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Accepted: 02/27/2023] [Indexed: 05/19/2023]
Abstract
SIGNIFICANCE Laser speckle contrast imaging (LSCI) gives a relative measure of microcirculatory perfusion. However, due to the limited information in single-exposure LSCI, models are inaccurate for skin tissue due to complex effects from e.g. static and dynamic scatterers, multiple Doppler shifts, and the speed-distribution of blood. It has been demonstrated how to account for these effects in laser Doppler flowmetry (LDF) using inverse Monte Carlo (MC) algorithms. This allows for a speed-resolved perfusion measure in absolute units %RBC × mm/s, improving the physiological interpretation of the data. Until now, this has been limited to a single-point LDF technique but recent advances in multi-exposure LSCI (MELSCI) enable the analysis in an imaging modality. AIM To present a method for speed-resolved perfusion imaging in absolute units %RBC × mm/s, computed from multi-exposure speckle contrast images. APPROACH An artificial neural network (ANN) was trained on a large simulated dataset of multi-exposure contrast values and corresponding speed-resolved perfusion. The dataset was generated using MC simulations of photon transport in randomized skin models covering a wide range of physiologically relevant geometrical and optical tissue properties. The ANN was evaluated on in vivo data sets captured during an occlusion provocation. RESULTS Speed-resolved perfusion was estimated in the three speed intervals 0 to 1 mm / s , 1 to 10 mm / s , and > 10 mm / s , with relative errors 9.8%, 12%, and 19%, respectively. The perfusion had a linear response to changes in both blood tissue fraction and blood flow speed and was less affected by tissue properties compared with single-exposure LSCI. The image quality was subjectively higher compared with LSCI, revealing previously unseen macro- and microvascular structures. CONCLUSIONS The ANN, trained on modeled data, calculates speed-resolved perfusion in absolute units from multi-exposure speckle contrast. This method facilitates the physiological interpretation of measurements using MELSCI and may increase the clinical impact of the technique.
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Affiliation(s)
- Martin Hultman
- Linköping University, Department of Biomedical Engineering, Linköping, Sweden
- Perimed AB, Stockholm, Sweden
- Address all correspondence to Martin Hultman,
| | - Marcus Larsson
- Linköping University, Department of Biomedical Engineering, Linköping, Sweden
| | - Tomas Strömberg
- Linköping University, Department of Biomedical Engineering, Linköping, Sweden
| | - Ingemar Fredriksson
- Linköping University, Department of Biomedical Engineering, Linköping, Sweden
- Perimed AB, Stockholm, Sweden
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3
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Walter AB, Jansen ED. Development of a platform for broadband, spectra-fitted, tissue optical phantoms. JOURNAL OF BIOMEDICAL OPTICS 2023; 28:025001. [PMID: 36814953 PMCID: PMC9940728 DOI: 10.1117/1.jbo.28.2.025001] [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: 11/04/2022] [Accepted: 01/24/2023] [Indexed: 06/18/2023]
Abstract
SIGNIFICANCE Current methods of producing optical phantoms are incapable of accurately capturing the wavelength-dependent properties of tissue critical for many optical modalities. AIM We aim to introduce a method of producing solid, inorganic phantoms whose wavelength-dependent optical properties can be matched to those of tissue over the wavelength range of 370 to 950 nm. APPROACH The concentration-dependent optical properties of 20 pigments were characterized and used to determine combinations that result in optimal fits compared to the target properties over the full spectrum. Phantoms matching the optical properties of muscle and nerve, the diffuse reflectance of pale and melanistic skin, and the chromophore concentrations of a computational skin model with varying oxygen saturation ( StO 2 ) were made with this method. RESULTS Both optical property phantoms were found to accurately mimic their respective tissues' absorption and scattering properties across the entire spectrum. The diffuse reflectance phantoms were able to closely approximate skin reflectance regardless of skin type. All three computational skin phantoms were found to have emulated chromophore concentrations close to the model, with an average percent error for the StO 2 of 4.31%. CONCLUSIONS This multipigment phantom platform represents a powerful tool for creating spectrally accurate tissue phantoms, which should increase the availability of standards for many optical techniques.
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Affiliation(s)
- Alec B. Walter
- Vanderbilt University, Department of Biomedical Engineering, Nashville, Tennessee, United States
- Vanderbilt University, Biophotonics Center, Nashville, Tennessee, United States
| | - E. Duco Jansen
- Vanderbilt University, Department of Biomedical Engineering, Nashville, Tennessee, United States
- Vanderbilt University, Biophotonics Center, Nashville, Tennessee, United States
- Vanderbilt University Medical Center, Department of Neurosurgery, Nashville, Tennessee, United States
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4
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Philipopoulos GP, Sharareh B, Ganesan G, Tromberg BJ, O’Sullivan TD, Schwarzkopf R. Characterizing tourniquet induced hemodynamics during total knee arthroplasty using diffuse optical spectroscopy. J Orthop Res 2023; 41:104-114. [PMID: 35289956 PMCID: PMC9475493 DOI: 10.1002/jor.25327] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 03/03/2022] [Accepted: 03/11/2022] [Indexed: 02/04/2023]
Abstract
Tourniquet use creates a reduced blood surgical field during total knee arthroplasty (TKA), however, prolonged ischemia may cause postoperative tourniquet complications. To understand the effects of tourniquet-induced ischemia, we performed a prospective observational study using quantitative broadband diffuse optical spectroscopy (DOS) to measure tissue hemodynamics and water and lipid concentrations before, during, and after tourniquet placement in subjects undergoing TKA. Data was collected for 6 months and, of the total subjects analyzed (n = 24), 22 were primary TKAs and 2 were revision TKA cases. We specifically investigated tourniquet-induced hemodynamics based upon subject-specific tissue composition and observed a significant relationship between the linear rate of deoxygenation after tourniquet inflation and water/lipid ratio (W/L, p < 0.0001) and baseline somatic tissue oxygen saturation, StO2 (p = 0.05). Subjects with a low W/L ratio exhibited a lower tissue metabolic rate of oxygen consumption, (tMRO2 ) (p = 0.008). Changes in deoxyhemoglobin [HbR] (p = 0.009) and lipid fraction (p = 0.001) were significantly different between high and low W/L subject groups during deoxygenation. No significant differences were observed for hemodynamics during reperfusion and total tourniquet time was neither significantly related to the hemodynamic hyperemic response (p = 0.73) nor the time to max StO2 after tourniquet release (p = 0.57). In conclusion, we demonstrate that DOS is capable of real-time monitoring of tissue hemodynamics distal to the tourniquet during TKA, and that tissue composition should be considered. DOS may help surgeons stratify hemodynamics based upon tissue composition and eventually aid the preoperative risk assessment of vascular occlusions from tourniquet use during TKA.
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Affiliation(s)
- George P. Philipopoulos
- University of California, Irvine, Beckman Laser Institute and Medical Clinic, Laser Microbeam and Medical Program, 1002 Health Sciences Road, Irvine, CA 92617, USA
| | - Behnam Sharareh
- University of Washington, Department of Orthopaedics and Sport Medicine, Seattle, WA, USA
| | - Goutham Ganesan
- University of California, Irvine, Beckman Laser Institute and Medical Clinic, Laser Microbeam and Medical Program, 1002 Health Sciences Road, Irvine, CA 92617, USA
- University of California Irvine, Institute for Clinical and Translation Science, 843 Hewitt Hall, Irvine, USA, 92617
| | - Bruce J. Tromberg
- University of California, Irvine, Beckman Laser Institute and Medical Clinic, Laser Microbeam and Medical Program, 1002 Health Sciences Road, Irvine, CA 92617, USA
| | - Thomas D. O’Sullivan
- University of Notre Dame, Department of Electrical Engineering, 275 Fitzpatrick Hall, Notre Dame, IN 46556 USA
| | - Ran Schwarzkopf
- NYU Langone Orthopaedic Hospital, Hospital for Joint Diseases, 301 East 17 Street, New York, NY 10003 USA
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5
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Lam JH, Tu KJ, Kim J, Kim S. Smartphone-based single snapshot spatial frequency domain imaging. BIOMEDICAL OPTICS EXPRESS 2022; 13:6497-6507. [PMID: 36589565 PMCID: PMC9774861 DOI: 10.1364/boe.470665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 10/30/2022] [Accepted: 11/03/2022] [Indexed: 06/17/2023]
Abstract
We report a handheld, smartphone-based spatial frequency domain imaging device. We first examined the linear dynamic range of the smartphone camera sensor. We then calculated optical properties for a series of liquid phantoms with varying concentrations of nigrosin ink and Intralipid, demonstrating separation of absorption and scattering. The device was then tested on a human wrist, where optical properties and hemoglobin-based chromophores were calculated. Finally, we performed an arterial occlusion on a human hand and captured hemodynamics using our device. We hope to lay the foundation for an accessible SFDI device with mass-market appeal designed for dermatological and cosmetic applications.
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Affiliation(s)
- Jesse H. Lam
- Dankook University, Beckman Laser Institute Korea, School of Medicine, Cheonan, Chungnam, Republic of Korea
| | - Kelsey J. Tu
- Dankook University, Department of Biomedical Engineering, Cheonan, Chungnam, Republic of Korea
| | - Jeonghun Kim
- Dankook University, Department of Biomedical Engineering, Cheonan, Chungnam, Republic of Korea
- MEDiThings Co. Ltd., Industry-Academia Cooperation, Dankook University, Cheonan, Chungnam, Republic of Korea
| | - Sehwan Kim
- Dankook University, Department of Biomedical Engineering, Cheonan, Chungnam, Republic of Korea
- University of California, Irvine, Beckman Laser Institute, Department of Biomedical Engineering, Irvine, CA, USA
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6
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Herranz Olazábal J, Wieringa F, Hermeling E, Van Hoof C. Camera-Derived Photoplethysmography (rPPG) and Speckle Plethysmography (rSPG): Comparing Reflective and Transmissive Mode at Various Integration Times Using LEDs and Lasers. SENSORS (BASEL, SWITZERLAND) 2022; 22:6059. [PMID: 36015822 PMCID: PMC9412985 DOI: 10.3390/s22166059] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 08/10/2022] [Accepted: 08/12/2022] [Indexed: 06/15/2023]
Abstract
Background: Although both speckle plethysmography (SPG) and photoplethysmography (PPG) examine pulsatile changes in the vasculature using opto-electronics, PPG has a long history, whereas SPG is relatively new and less explored. The aim of this study was to compare the effects of integration time and light-source coherence on signal quality and waveform morphology for reflective and transmissive rSPG and rPPG. Methods: (A) Using time-domain multiplexing, we illuminated 10 human index fingers with pulsed lasers versus LEDs (both at 639 and 850 nm), in transmissive versus reflective mode. A synchronized camera (Basler acA2000-340 km, 25 cm distance, 200 fps) captured and demultiplexed four video channels (50 fps/channel) in four stages defined by illumination mode. From all video channels, we derived rPPG and rSPG, and applied a signal quality index (SQI, scale: Good > 0.95; Medium 0.95−0.85; Low 0.85−0.8; Negligible < 0.8); (B) For transmission videos only, we additionally calculated the intensity threshold area (ITA), as the area of the imaging exceeding a certain intensity value and used linear regression analysis to understand unexpected similarities between rPPG and rSPG. Results: All mean SQI-values. Reflective mode: Laser-rSPG > 0.965, LED-rSPG < 0.78, rPPG < 0.845. Transmissive mode: 0.853−0.989 for rSPG and rPPG at all illumination settings. Coherent mode: Reflective rSPG > 0.951, reflective rPPG < 0.740, transmissive rSPG and rPPG 0.990−0.898. Incoherent mode: Reflective all <0.798 and transmissive all 0.92−0.987. Linear regressions revealed similar R2 values of rPPG with rSPG (R2 = 0.99) and ITA (R2 = 0.98); Discussion: Laser-rSPG and LED-rPPG produced different waveforms in reflection, but not in transmission. We created the concept of ITA to investigate this behavior. Conclusions: Reflective Laser-SPG truly originated from coherence. Transmissive Laser-rSPG showed a loss of speckles, accompanied by waveform changes towards rPPG. Diffuse spatial intensity modulation polluted spatial-mode SPG.
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Affiliation(s)
- Jorge Herranz Olazábal
- IMEC, 3000 Leuven, Belgium
- Faculty of Engineering Science, Katholieke Universiteit Leuven (KUL), 3000 Leuven, Belgium
| | - Fokko Wieringa
- IMEC NL, 5656 AE Eindhoven, The Netherlands
- Division of Internal Medicine, Department of Nephrology, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands
| | | | - Chris Van Hoof
- IMEC, 3000 Leuven, Belgium
- Faculty of Engineering Science, Katholieke Universiteit Leuven (KUL), 3000 Leuven, Belgium
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7
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Taylor-Williams M, Spicer G, Bale G, Bohndiek SE. Noninvasive hemoglobin sensing and imaging: optical tools for disease diagnosis. JOURNAL OF BIOMEDICAL OPTICS 2022; 27:JBO-220074VR. [PMID: 35922891 PMCID: PMC9346606 DOI: 10.1117/1.jbo.27.8.080901] [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: 04/06/2022] [Accepted: 06/27/2022] [Indexed: 05/08/2023]
Abstract
SIGNIFICANCE Measurement and imaging of hemoglobin oxygenation are used extensively in the detection and diagnosis of disease; however, the applied instruments vary widely in their depth of imaging, spatiotemporal resolution, sensitivity, accuracy, complexity, physical size, and cost. The wide variation in available instrumentation can make it challenging for end users to select the appropriate tools for their application and to understand the relative limitations of different methods. AIM We aim to provide a systematic overview of the field of hemoglobin imaging and sensing. APPROACH We reviewed the sensing and imaging methods used to analyze hemoglobin oxygenation, including pulse oximetry, spectral reflectance imaging, diffuse optical imaging, spectroscopic optical coherence tomography, photoacoustic imaging, and diffuse correlation spectroscopy. RESULTS We compared and contrasted the ability of different methods to determine hemoglobin biomarkers such as oxygenation while considering factors that influence their practical application. CONCLUSIONS We highlight key limitations in the current state-of-the-art and make suggestions for routes to advance the clinical use and interpretation of hemoglobin oxygenation information.
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Affiliation(s)
- Michaela Taylor-Williams
- University of Cambridge, Department of Physics, Cavendish Laboratory, Cambridge, United Kingdom, United Kingdom
- University of Cambridge, Cancer Research UK Cambridge Institute, Cambridge, United Kingdom, United Kingdom
| | - Graham Spicer
- University of Cambridge, Department of Physics, Cavendish Laboratory, Cambridge, United Kingdom, United Kingdom
- University of Cambridge, Cancer Research UK Cambridge Institute, Cambridge, United Kingdom, United Kingdom
| | - Gemma Bale
- University of Cambridge, Department of Physics, Cavendish Laboratory, Cambridge, United Kingdom, United Kingdom
- University of Cambridge, Electrical Division, Department of Engineering, Cambridge, United Kingdom, United Kingdom
| | - Sarah E Bohndiek
- University of Cambridge, Department of Physics, Cavendish Laboratory, Cambridge, United Kingdom, United Kingdom
- University of Cambridge, Cancer Research UK Cambridge Institute, Cambridge, United Kingdom, United Kingdom
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8
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Lertsakdadet BS, Kennedy GT, Stone R, Kowalczewski C, Kowalczewski AC, Natesan S, Christy RJ, Durkin AJ, Choi B. Assessing multimodal optical imaging of perfusion in burn wounds. Burns 2022; 48:799-807. [PMID: 34696954 DOI: 10.1016/j.burns.2021.08.026] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 08/04/2021] [Accepted: 08/31/2021] [Indexed: 12/15/2022]
Abstract
A critical need exists for early, accurate diagnosis of burn wound severity to help identify the course of treatment and outcome of the wound. Laser speckle imaging (LSI) is a promising blood perfusion imaging approach, but it does not account for changes in tissue optical properties that can occur with burn wounds, which are highly dynamic environments. Here, we studied optical property dynamics following burn injury and debridement and the associated impact on interpretation of LSI measurements of skin perfusion. We used spatial frequency domain imaging (SFDI) measurements of tissue optical properties to study the impact of burn-induced changes in these properties on LSI measurements. An established preclinical porcine model of burn injury was used (n = 8). SFDI and LSI data were collected from burn wounds of varying severity. SFDI measurements demonstrate that optical properties change in response to burn injury in a porcine model. We then apply theoretical modeling to demonstrate that the measured range of optical property changes can affect the interpretation of LSI measurements of blood flow, but this effect is minimal for most of the measured data. Collectively, our results indicate that, even with a dynamic burn wound environment, blood-flow measurements with LSI can serve as an appropriate strategy for accurate assessment of burn severity.
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Affiliation(s)
- Ben S Lertsakdadet
- Beckman Laser Institute and Medical Clinic, University of California, Irvine, CA 92612, USA; Department of Biomedical Engineering, University of California, Irvine, CA, 92697, USA.
| | - Gordon T Kennedy
- Beckman Laser Institute and Medical Clinic, University of California, Irvine, CA 92612, USA.
| | - Randolph Stone
- United States Army Institute of Surgical Research, 36950 Chambers Pass, Fort Sam Houston, TX 78234, USA.
| | - Christine Kowalczewski
- United States Army Institute of Surgical Research, 36950 Chambers Pass, Fort Sam Houston, TX 78234, USA.
| | - Andrew C Kowalczewski
- United States Army Institute of Surgical Research, 36950 Chambers Pass, Fort Sam Houston, TX 78234, USA.
| | - Shanmugasundaram Natesan
- United States Army Institute of Surgical Research, 36950 Chambers Pass, Fort Sam Houston, TX 78234, USA.
| | - Robert J Christy
- United States Army Institute of Surgical Research, 36950 Chambers Pass, Fort Sam Houston, TX 78234, USA.
| | - Anthony J Durkin
- Beckman Laser Institute and Medical Clinic, University of California, Irvine, CA 92612, USA; Department of Biomedical Engineering, University of California, Irvine, CA, 92697, USA.
| | - Bernard Choi
- Beckman Laser Institute and Medical Clinic, University of California, Irvine, CA 92612, USA; Department of Biomedical Engineering, University of California, Irvine, CA, 92697, USA; Department of Surgery, University of California, Irvine, CA, 92697, USA; Edwards Lifesciences Center for Advanced Cardiovascular Technology, University of California, Irvine, CA, 92697, USA.
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9
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Majedy M, Saager RB, Strömberg T, Larsson M, Salerud EG. Spectral characterization of liquid hemoglobin phantoms with varying oxygenation states. JOURNAL OF BIOMEDICAL OPTICS 2021; 27:JBO-210213SSR. [PMID: 34850613 PMCID: PMC8632618 DOI: 10.1117/1.jbo.27.7.074708] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 11/16/2021] [Indexed: 06/13/2023]
Abstract
SIGNIFICANCE For optical methods to accurately assess hemoglobin oxygen saturation in vivo, an independently verifiable tissue-like standard is required for validation. For this purpose, we propose three hemoglobin preparations and evaluate methods to characterize them. AIM To spectrally characterize three different hemoglobin preparations using multiple spectroscopic methods and to compare their absorption spectra to commonly used reference spectra. APPROACH Absorption spectra of three hemoglobin preparations in solution were characterized using spectroscopic collimated transmission: whole blood, lysed blood, and ferrous-stabilized hemoglobin. Tissue-mimicking phantoms composed of Intralipid, and the hemoglobin solutions were characterized using spatial frequency-domain spectroscopy (SFDS) and enhanced perfusion and oxygen saturation (EPOS) techniques while using yeast to deplete oxygen. RESULTS All hemoglobin preparations exhibited similar absorption spectra when accounting for methemoglobin and scattering in their oxyhemoglobin and deoxyhemoglobin forms, respectively. However, systematic differences were observed in the fitting depending on the reference spectra used. For the tissue-mimicking phantoms, SFDS measurements at the surface of the phantom were affected by oxygen diffusion at the interface with air, associated with higher values than for the EPOS system. CONCLUSIONS We show the validity of different blood phantoms and what considerations need to be addressed in each case to utilize them equivalently.
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Affiliation(s)
- Motasam Majedy
- Linköping University, Department of Biomedical Engineering, Linköping, Sweden
| | - Rolf B. Saager
- 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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10
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van Manen L, Birkhoff WAJ, Eggermont J, Hoveling RJM, Nicklin P, Burggraaf J, Wilson R, Mieog JSD, Robinson DJ, Vahrmeijer AL, Bradbury MS, Dijkstra J. Detection of cutaneous oxygen saturation using a novel snapshot hyperspectral camera: a feasibility study. Quant Imaging Med Surg 2021; 11:3966-3977. [PMID: 34476182 DOI: 10.21037/qims-21-46] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 04/15/2021] [Indexed: 11/06/2022]
Abstract
Background Tissue necrosis, a consequence of inadequate tissue oxygenation, is a common post-operative complication. As current surgical assessments are often limited to visual and tactile feedback, additional techniques that can aid in the interrogation of tissue viability are needed to improve patient outcomes. In this bi-institutional pilot study, the performance of a novel snapshot hyperspectral imaging camera to detect superficial cutaneous oxygen saturation (StO2) was evaluated. Methods Healthy human volunteers were recruited at two participating centers. Cutaneous StO2 of the forearm was determined by a snapshot hyperspectral camera on two separate study days during occlusion-reperfusion of the brachial artery and after induction of local vasodilation. To calculate the blood StO2 at each pixel in the multispectral image, spectra were selected, and fitting was performed over wavelengths ranging from 470 to 950 nm. Results Quantitative detection of physiological changes in cutaneous StO2 levels was feasible in all sixteen volunteers. A significant (P<0.001) decrease in cutaneous StO2 levels from 78.3% (SD: 15.3) at baseline to 60.6% (SD: 19.8) at the end of occlusion phase was observed, although StO2 levels returned to baseline after five minutes. Mean cutaneous StO2 values were similar in the same subjects on separate study days (Pearson R2: 0.92 and 0.77, respectively) at both centers. Local vasodilation did not yield significant changes in cutaneous StO2 values. Conclusions This pilot study demonstrated the feasibility of a snapshot hyperspectral camera for detecting quantitative physiological changes in cutaneous StO2 in normal human volunteers, and serves as a precursor for further validation in perioperative studies.
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Affiliation(s)
- Labrinus van Manen
- Department of Surgery, Leiden University Medical Center, Leiden, The Netherlands
| | | | - Jeroen Eggermont
- Leiden University Medical Center, Division of Image Processing, Department of Radiology, Leiden, The Netherlands
| | | | - Philip Nicklin
- Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Jacobus Burggraaf
- Department of Surgery, Leiden University Medical Center, Leiden, The Netherlands.,Centre for Human Drug Research, Leiden, The Netherlands
| | - Roger Wilson
- Department of Anesthesiology, Critical Care Medicine, and Surgery, Memorial Sloan Kettering Cancer Center Research, New York, NY, USA
| | - J Sven D Mieog
- Department of Surgery, Leiden University Medical Center, Leiden, The Netherlands
| | - Dominic J Robinson
- Erasmus Medical Center, Center for Optical Diagnostics and Therapy, Department of Otorhinolaryngology and Head and Neck Surgery, Rotterdam, The Netherlands
| | | | - Michelle S Bradbury
- Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, USA.,MSK-Cornell Center for Translation of Cancer Nanomedicines, Memorial Sloan Kettering Cancer Center, New York, NY, USA.,Molecular Pharmacology Program, Sloan Kettering Institute for Cancer Research, New York, NY, USA
| | - Jouke Dijkstra
- Leiden University Medical Center, Division of Image Processing, Department of Radiology, Leiden, The Netherlands
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11
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Lopez-Pascual A, Trayhurn P, Martínez JA, González-Muniesa P. Oxygen in Metabolic Dysfunction and Its Therapeutic Relevance. Antioxid Redox Signal 2021; 35:642-687. [PMID: 34036800 DOI: 10.1089/ars.2019.7901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Significance: In recent years, a number of studies have shown altered oxygen partial pressure at a tissue level in metabolic disorders, and some researchers have considered oxygen to be a (macro) nutrient. Oxygen availability may be compromised in obesity and several other metabolism-related pathological conditions, including sleep apnea-hypopnea syndrome, the metabolic syndrome (which is a set of conditions), type 2 diabetes, cardiovascular disease, and cancer. Recent Advances: Strategies designed to reduce adiposity and its accompanying disorders have been mainly centered on nutritional interventions and physical activity programs. However, novel therapies are needed since these approaches have not been sufficient to counteract the worldwide increasing rates of metabolic disorders. In this regard, intermittent hypoxia training and hyperoxia could be potential treatments through oxygen-related adaptations. Moreover, living at a high altitude may have a protective effect against the development of abnormal metabolic conditions. In addition, oxygen delivery systems may be of therapeutic value for supplying the tissue-specific oxygen requirements. Critical Issues: Precise in vivo methods to measure oxygenation are vital to disentangle some of the controversies related to this research area. Further, it is evident that there is a growing need for novel in vitro models to study the potential pathways involved in metabolic dysfunction to find appropriate therapeutic targets. Future Directions: Based on the existing evidence, it is suggested that oxygen availability has a key role in obesity and its related comorbidities. Oxygen should be considered in relation to potential therapeutic strategies in the treatment and prevention of metabolic disorders. Antioxid. Redox Signal. 35, 642-687.
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Affiliation(s)
- Amaya Lopez-Pascual
- Department of Nutrition, Food Science and Physiology, School of Pharmacy and Nutrition, Centre for Nutrition Research, University of Navarra, Pamplona, Spain.,Neuroendocrine Cell Biology, Lund University Diabetes Centre, Lund University, Malmö, Sweden
| | - Paul Trayhurn
- Obesity Biology Unit, University of Liverpool, Liverpool, United Kingdom.,Clore Laboratory, The University of Buckingham, Buckingham, United Kingdom
| | - J Alfredo Martínez
- Department of Nutrition, Food Science and Physiology, School of Pharmacy and Nutrition, Centre for Nutrition Research, University of Navarra, Pamplona, Spain.,IdiSNA, Navarra Institute for Health Research, Pamplona, Spain.,CIBERobn Physiopathology of Obesity and Nutrition, Centre of Biomedical Research Network, ISCIII, Madrid, Spain.,Precision Nutrition and Cardiometabolic Health, IMDEA Food, Madrid Institute for Advanced Studies, Madrid, Spain
| | - Pedro González-Muniesa
- Department of Nutrition, Food Science and Physiology, School of Pharmacy and Nutrition, Centre for Nutrition Research, University of Navarra, Pamplona, Spain.,IdiSNA, Navarra Institute for Health Research, Pamplona, Spain.,CIBERobn Physiopathology of Obesity and Nutrition, Centre of Biomedical Research Network, ISCIII, Madrid, Spain
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12
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Lam JH, Hill B, Quang T, Amelard R, Kim S, Yazdi HS, Warren RV, Cutler KB, Tromberg BJ. Multi-modal diffuse optical spectroscopy for high-speed monitoring and wide-area mapping of tissue optical properties and hemodynamics. JOURNAL OF BIOMEDICAL OPTICS 2021; 26:JBO-210158RR. [PMID: 34390234 PMCID: PMC8362892 DOI: 10.1117/1.jbo.26.8.085002] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 07/30/2021] [Indexed: 05/15/2023]
Abstract
SIGNIFICANCE Diffuse optical spectroscopic imaging (DOSI) is a versatile technology sensitive to changes in tissue composition and hemodynamics and has been used for a wide variety of clinical applications. Specific applications have prompted the development of versions of the DOSI technology to fit specific clinical needs. This work describes the development and characterization of a multi-modal DOSI (MM-DOSI) system that can acquire metabolic, compositional, and pulsatile information at multiple penetration depths in a single hardware platform. Additionally, a 3D tracking system is integrated with MM-DOSI, which enables registration of the acquired data to the physical imaging area. AIM We demonstrate imaging, layered compositional analysis, and metabolism tracking capabilities using a single MM-DOSI system on optical phantoms as well as in vivo human tissue. APPROACH We characterize system performance with a silicone phantom containing an embedded object. To demonstrate multi-layer sensitivity, we imaged human calf tissue with a 4.8-mm skin-adipose thickness. Human thenar tissue was also measured using a combined broadband DOSI and continuous-wave near-infrared spectroscopy method (∼15 Hz acquisition rate). RESULTS High-resolution optical property maps of absorption (μa) and reduced scattering (μs ' ) were recovered on the phantom by capturing over 1000 measurement points in under 5 minutes. On human calf tissue, we show two probing depth layers have significantly different (p < 0.001) total-hemo/myoglobin and μs ' composition. On thenar tissue, we calculate tissue arterial oxygen saturation, venous oxygen saturation, and tissue metabolic rate of oxygen consumption during baseline and after release of an arterial occlusion. CONCLUSIONS The MM-DOSI can switch between collection of broadband spectra, high-resolution images, or multi-depth hemodynamics without any hardware reconfiguration. We conclude that MM-DOSI enables acquisition of high resolution, multi-modal data consolidated in a single platform, which can provide a more comprehensive understanding of tissue hemodynamics and composition for a wide range of clinical applications.
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Affiliation(s)
- Jesse H. Lam
- University of California, Irvine, Beckman Laser Institute, Department of Biomedical Engineering, Irvine, California, United States
- Dankook University, Beckman Laser Institute Korea, School of Medicine, Cheonan, Chungnam, Republic of Korea
| | - Brian Hill
- National Institutes of Health, National Institute of Child Health and Human Development, Bethesda, Maryland, United States
| | - Timothy Quang
- National Institutes of Health, National Institute of Child Health and Human Development, Bethesda, Maryland, United States
| | - Robert Amelard
- KITE-Toronto Rehabilitation Institute, University Health Network, Toronto, Ontario, Canada
- Schlegel-UW Research Institute for Aging, Waterloo, Ontario, Canada
| | - Sehwan Kim
- University of California, Irvine, Beckman Laser Institute, Department of Biomedical Engineering, Irvine, California, United States
- Dankook University, Beckman Laser Institute Korea, School of Medicine, Cheonan, Chungnam, Republic of Korea
| | - Hossein S. Yazdi
- University of California, Irvine, Beckman Laser Institute, Department of Biomedical Engineering, Irvine, California, United States
| | - Robert V. Warren
- University of California, Irvine, Beckman Laser Institute, Department of Biomedical Engineering, Irvine, California, United States
| | - Kyle B. Cutler
- University of California, Irvine, Beckman Laser Institute, Department of Biomedical Engineering, Irvine, California, United States
| | - Bruce J. Tromberg
- University of California, Irvine, Beckman Laser Institute, Department of Biomedical Engineering, Irvine, California, United States
- National Institutes of Health, National Institute of Biomedical Imaging and Bioengineering, Bethesda, Maryland, United States
- Address all correspondence to Bruce J. Tromberg,
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13
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Wang HL, Chen JW, Yang SH, Lo YC, Pan HC, Liang YW, Wang CF, Yang Y, Kuo YT, Lin YC, Chou CY, Lin SH, Chen YY. Multimodal Optical Imaging to Investigate Spatiotemporal Changes in Cerebrovascular Function in AUDA Treatment of Acute Ischemic Stroke. Front Cell Neurosci 2021; 15:655305. [PMID: 34149359 PMCID: PMC8209306 DOI: 10.3389/fncel.2021.655305] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Accepted: 05/10/2021] [Indexed: 01/03/2023] Open
Abstract
Administration of 12-(3-adamantan-1-yl-ureido)-dodecanoic acid (AUDA) has been demonstrated to alleviate infarction following ischemic stroke. Reportedly, the main effect of AUDA is exerting anti-inflammation and neovascularization via the inhibition of soluble epoxide hydrolase. However, the major contribution of this anti-inflammation and neovascularization effect in the acute phase of stroke is not completely elucidated. To investigate the neuroprotective effects of AUDA in acute ischemic stroke, we combined laser speckle contrast imaging and optical intrinsic signal imaging techniques with the implantation of a lab-designed cranial window. Forepaw stimulation was applied to assess the functional changes via measuring cerebral metabolic rate of oxygen (CMRO2) that accompany neural activity. The rats that received AUDA in the acute phase of photothrombotic ischemia stroke showed a 30.5 ± 8.1% reduction in the ischemic core, 42.3 ± 15.1% reduction in the ischemic penumbra (p < 0.05), and 42.1 ± 4.6% increase of CMRO2 in response to forepaw stimulation at post-stroke day 1 (p < 0.05) compared with the control group (N = 10 for each group). Moreover, at post-stroke day 3, increased functional vascular density was observed in AUDA-treated rats (35.9 ± 1.9% higher than that in the control group, p < 0.05). At post-stroke day 7, a 105.4% ± 16.4% increase of astrocytes (p < 0.01), 30.0 ± 10.9% increase of neurons (p < 0.01), and 65.5 ± 15.0% decrease of microglia (p < 0.01) were observed in the penumbra region in AUDA-treated rats (N = 5 for each group). These results suggested that AUDA affects the anti-inflammation at the beginning of ischemic injury and restores neuronal metabolic rate of O2 and tissue viability. The neovascularization triggered by AUDA restored CBF and may contribute to ischemic infarction reduction at post-stroke day 3. Moreover, for long-term neuroprotection, astrocytes in the penumbra region may play an important role in protecting neurons from apoptotic injury.
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Affiliation(s)
- Han-Lin Wang
- Department of Biomedical Engineering, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Jia-Wei Chen
- Department of Biomedical Engineering, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Shih-Hung Yang
- Department of Mechanical Engineering, National Cheng Kung University, Tainan, Taiwan
| | - Yu-Chun Lo
- The Ph.D. Program for Neural Regenerative Medicine, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan
| | - Han-Chi Pan
- National Laboratory Animal Center, Taipei, Taiwan
| | - Yao-Wen Liang
- Department of Biomedical Engineering, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Ching-Fu Wang
- Department of Biomedical Engineering, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Yi Yang
- Department of Biomedical Engineering, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Yun-Ting Kuo
- Department of Biomedical Engineering, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Yi-Chen Lin
- Department of Biomedical Engineering, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Chin-Yu Chou
- Department of Biomedical Engineering, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Sheng-Huang Lin
- Department of Neurology, Hualien Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Hualien, Taiwan.,Department of Neurology, School of Medicine, Tzu Chi University, Hualien, Taiwan
| | - You-Yin Chen
- Department of Biomedical Engineering, National Yang Ming Chiao Tung University, Taipei, Taiwan.,The Ph.D. Program for Neural Regenerative Medicine, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan
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14
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Meijer RPJ, van Manen L, Hartgrink HH, Burggraaf J, Gioux S, Vahrmeijer AL, Mieog JSD. Quantitative dynamic near-infrared fluorescence imaging using indocyanine green for analysis of bowel perfusion after mesenteric resection. JOURNAL OF BIOMEDICAL OPTICS 2021; 26:JBO-200408LR. [PMID: 34109769 PMCID: PMC8189572 DOI: 10.1117/1.jbo.26.6.060501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 04/23/2021] [Indexed: 06/12/2023]
Abstract
SIGNIFICANCE Near-infrared (NIR) fluorescence imaging using indocyanine green (ICG) has proven to be a feasible application for real-time intraoperative assessment of tissue perfusion, although quantification of NIR fluorescence signals is pivotal for standardized assessment of tissue perfusion. AIM Four patients are described with possible compromised bowel perfusion after mesenteric resection. Based on these patients we want to emphasize the difficulties in the quantification of NIR fluorescence imaging for perfusion analysis. APPROACH During image-guided fluorescence assessment, 5 mg of ICG (2.5 mg / ml) was intravenously administered by the anesthesiologist. NIR fluorescence imaging was done with the open camera system of Quest Medical Imaging. Fluorescence data taken from the regions of interest (bowel at risk, transition zone of bowel at risk and adjacent normally perfused bowel, and normally perfused reference bowel) were quantitatively analyzed after surgery for fluorescence intensity-and perfusion time-related parameters. RESULTS Bowel perfusion, as assessed clinically by independent surgeons based on NIR fluorescence imaging, resulted in different treatment strategies, three with excellent clinical outcome, but one with a perfusion related complication. Post-surgery quantitative analysis of fluorescence dynamics showed different patterns in the affected bowel segment compared to the unaffected reference segments for the four patients. CONCLUSIONS Similar intraoperative fluorescence results could lead to different surgical treatment strategies, which demonstrated the difficulties in interpretation of uncorrected fluorescence signals. Real-time quantification and standardization of NIR fluorescence perfusion imaging could probably aid surgeons in the nearby future.
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Affiliation(s)
- Ruben P. J. Meijer
- Leiden University Medical Center, Department of Surgery, Leiden, The Netherlands
- Centre for Human Drug Research, Leiden, The Netherlands
| | - Labrinus van Manen
- Leiden University Medical Center, Department of Surgery, Leiden, The Netherlands
| | - Henk H. Hartgrink
- Leiden University Medical Center, Department of Surgery, Leiden, The Netherlands
| | - Jacobus Burggraaf
- Leiden University Medical Center, Department of Surgery, Leiden, The Netherlands
- Centre for Human Drug Research, Leiden, The Netherlands
| | - Sylvain Gioux
- University of Strasbourg, ICube Laboratory, Strasbourg, France
| | | | - J. Sven D. Mieog
- Leiden University Medical Center, Department of Surgery, Leiden, The Netherlands
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15
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Wilson RH, Crouzet C, Torabzadeh M, Bazrafkan A, Maki N, Tromberg BJ, Akbari Y, Choi B. High-speed quantitative optical imaging of absolute metabolism in the rat cortex. NEUROPHOTONICS 2021; 8:025001. [PMID: 33842666 PMCID: PMC8027868 DOI: 10.1117/1.nph.8.2.025001] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 03/17/2021] [Indexed: 05/10/2023]
Abstract
Significance: Quantitative measures of blood flow and metabolism are essential for improved assessment of brain health and response to ischemic injury. Aim: We demonstrate a multimodal technique for measuring the cerebral metabolic rate of oxygen ( CMRO 2 ) in the rodent brain on an absolute scale ( μ M O 2 / min ). Approach: We use laser speckle imaging at 809 nm and spatial frequency domain imaging at 655, 730, and 850 nm to obtain spatiotemporal maps of cerebral blood flow, tissue absorption ( μ a ), and tissue scattering ( μ s ' ). Knowledge of these three values enables calculation of a characteristic blood flow speed, which in turn is input to a mathematical model with a "zero-flow" boundary condition to calculate absolute CMRO 2 . We apply this method to a rat model of cardiac arrest (CA) and cardiopulmonary resuscitation. With this model, the zero-flow condition occurs during entry into CA. Results: The CMRO 2 values calculated with our method are in good agreement with those measured with magnetic resonance and positron emission tomography by other groups. Conclusions: Our technique provides a quantitative metric of absolute cerebral metabolism that can potentially be used for comparison between animals and longitudinal monitoring of a single animal over multiple days. Though this report focuses on metabolism in a model of ischemia and reperfusion, this technique can potentially be applied to far broader types of acute brain injury and whole-body pathological occurrences.
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Affiliation(s)
- Robert H. Wilson
- University of California, Department of Medicine, Irvine, California, United States
- University of California, Beckman Laser Institute, Irvine, California, United States
- University of California, Health Policy Research Institute, Irvine, California, United States
- Address all correspondence to Bernard Choi, ; Yama Akbari, ; Robert H. Wilson,
| | - Christian Crouzet
- University of California, Beckman Laser Institute, Irvine, California, United States
| | - Mohammad Torabzadeh
- University of California, Department of Medicine, Irvine, California, United States
- University of California, Department of Biomedical Engineering, Irvine, California, United States
| | - Afsheen Bazrafkan
- University of California, Department of Neurology, Irvine, California, United States
| | - Niki Maki
- University of California, Department of Neurology, Irvine, California, United States
| | - Bruce J. Tromberg
- University of California, Beckman Laser Institute, Irvine, California, United States
| | - Yama Akbari
- University of California, Department of Neurology, Irvine, California, United States
- University of California, School of Medicine, Irvine, California, United States
- Address all correspondence to Bernard Choi, ; Yama Akbari, ; Robert H. Wilson,
| | - Bernard Choi
- University of California, Beckman Laser Institute, Irvine, California, United States
- University of California, Department of Biomedical Engineering, Irvine, California, United States
- University of California, Department of Surgery, Irvine, California, United States
- Address all correspondence to Bernard Choi, ; Yama Akbari, ; Robert H. Wilson,
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16
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Hultman M, Larsson M, Strömberg T, Fredriksson I. Real-time video-rate perfusion imaging using multi-exposure laser speckle contrast imaging and machine learning. JOURNAL OF BIOMEDICAL OPTICS 2020; 25:JBO-200207R. [PMID: 33191685 PMCID: PMC7666876 DOI: 10.1117/1.jbo.25.11.116007] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 10/21/2020] [Indexed: 05/03/2023]
Abstract
SIGNIFICANCE Multi-exposure laser speckle contrast imaging (MELSCI) estimates microcirculatory blood perfusion more accurately than single-exposure LSCI. However, the technique has been hampered by technical limitations due to massive data throughput requirements and nonlinear inverse search algorithms, limiting it to an offline technique where data must be postprocessed. AIM To present an MELSCI system capable of continuous acquisition and processing of MELSCI data, enabling real-time video-rate perfusion imaging with high accuracy. APPROACH The MELSCI algorithm was implemented in programmable hardware (field programmable gate array) closely interfaced to a high-speed CMOS sensor for real-time calculation. Perfusion images were estimated in real-time from the MELSCI data using an artificial neural network trained on simulated data. The MELSCI perfusion was compared to two existing single-exposure metrics both quantitatively in a controlled phantom experiment and qualitatively in vivo. RESULTS The MELSCI perfusion shows higher signal dynamics compared to both single-exposure metrics, both spatially and temporally where heartbeat-related variations are resolved in much greater detail. The MELSCI perfusion is less susceptible to measurement noise and is more linear with respect to laser Doppler perfusion in the phantom experiment (R2 = 0.992). CONCLUSIONS The presented MELSCI system allows for real-time acquisition and calculation of high-quality perfusion at 15.6 frames per second.
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Affiliation(s)
- Martin Hultman
- Linköping University, Department of Biomedical Engineering, Linköping, Sweden
- Address all correspondence to Martin Hultman,
| | - Marcus Larsson
- Linköping University, Department of Biomedical Engineering, Linköping, Sweden
| | - Tomas Strömberg
- Linköping University, Department of Biomedical Engineering, Linköping, Sweden
| | - Ingemar Fredriksson
- Linköping University, Department of Biomedical Engineering, Linköping, Sweden
- Perimed AB, Järfälla, Stockholm, Sweden
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17
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Bu L, Xu N, Wang Y, Liu H. Decreased low-frequency brain effective connectivity in seafarers during voyages: a functional near-infrared spectroscopy study. Physiol Meas 2020; 41:095003. [PMID: 32759489 DOI: 10.1088/1361-6579/abad13] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE During voyages, seafarers experience psychological problems that act to decrease operational safety. Psychological problems in seafarers can lead to changes in functional brain networks. This study investigated the low-frequency brain effective connectivity (EC) in seafarers during voyages by using the coupling strength (CS) of functional near-infrared spectroscopy (fNIRS) imaging. APPROACH This study recruited 15 seafarers (seafarer group) working on a container ship and 15 healthy age-matched controls (control group). The EC was assessed using dynamic Bayesian inference (DBI) of the oxygenated hemoglobin concentration (delta HbO2) as measured through a 14-channel fNIRS system. These channels covered the left and right prefrontal cortices (LPFC/RPFC), left and right motor cortices (LMC/RMC), and left and right occipital lobes (LOL/ROL). MAIN RESULTS The EC levels of LPFC to RMC (F = 4.239, p = 0.049), LPFC to ROL (F = 5.385, p = 0.028), LOL to RPFC (F = 11.128, p = 0.002), ROL to RPFC (F = 10.714, p = 0.003) and LMC to ROL (F= 6.136, p = 0.02) were significantly lower in the seafarer group than in the control group. Correlation analysis revealed that the patient health questionnaire-9 (PHQ-9) scores were positively correlated with the systolic blood pressure (SBP) values, delta HbO2 values and EC levels, respectively. Meanwhile, the correlation analysis revealed that the SBP values significantly positively correlated with the CS values. SIGNIFICANCE Decreased EC levels may be a marker of psychological subhealth in seafarers. The approach combines fNIRS and PHQ-9 scores, providing a quantitative method for the assessment of mental health problems and further help with better rehabilitation designs in seafarers during voyages.
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Affiliation(s)
- Lingguo Bu
- Department of Physical Medicine and Rehabilitation, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250012, People's Republic of China. School of Mechanical and Aerospace Engineering, Nanyang Technological University, 639798, Singapore
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18
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Lu H, Gong Z, Song Y, Jiang R. Application of P(jv-a) CO 2 in monitoring cerebral oxygen supply-demand balance in injured brain. J Clin Neurosci 2019; 71:213-216. [PMID: 31864831 DOI: 10.1016/j.jocn.2019.11.028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 10/07/2019] [Accepted: 11/26/2019] [Indexed: 10/25/2022]
Abstract
Transcranial Doppler sonography (TCD) assayed cerebral blood flow (CBF) may vary between different intracranial pathologies. Blood gas analysis of the jugular bulb provides a novel way to estimate the global relationship between CBF and oxygen metabolism. In this study, 25 patients with brain trauma, spontaneous intracerebral hemorrhage, and acute cerebral infarction were recruited. Jugular venous oxygen saturation (SjvO2) increased significantly at different time points after hyperventilation (p < 0.05). A negative correlation between the partial pressure of CO2 between jugular venous bulb and radial artery blood (P(jv-a)CO2) and CBF could be observed in acute brain injury and spontaneous intracerebral hemorrhage groups, while P(jv-a)CO2 and CBF show positive correlation in acute cerebral infarction group. Our results suggest that serial P(jv-a)CO2 analysis combing with SjvO2 can be utilized to monitor the change of CBF for patients undergoing craniocerebral surgery.
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Affiliation(s)
- Huaihai Lu
- Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin 300052, China
| | - Zhitao Gong
- Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin 300052, China
| | - Yiming Song
- Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin 300052, China
| | - Rongcai Jiang
- Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin 300052, China.
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19
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Bloygrund H, Franjy-Tal Y, Rosenzweig T, Abookasis D. Multiparameter wide-field integrated optical imaging system-based spatially modulated illumination and laser speckles in model of tissue injuries. JOURNAL OF BIOPHOTONICS 2019; 12:e201900141. [PMID: 31187933 DOI: 10.1002/jbio.201900141] [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: 04/16/2019] [Revised: 06/03/2019] [Accepted: 06/07/2019] [Indexed: 06/09/2023]
Abstract
In this report, an integrated optical platform based on spatial illumination together with laser speckle contrast technique was utilized to measure multiple parameters in live tissue including absorption, scattering, saturation, composition, metabolism, and blood flow. Measurements in three models of tissue injury including drug toxicity, artery occlusion, and acute hyperglycemia were used to test the efficacy of this system. With this hybrid apparatus, a series of structured light patterns at low and high spatial frequencies are projected onto the tissue surface and diffuse reflected light is captured by a CCD camera. A six position filter wheel, equipped with four bandpass filters centered at wavelengths of 650, 690, 800 and 880 nm is placed in front of the camera. Then, light patterns are blocked and a laser source at 650 nm illuminates the tissue while the diffusely reflected light is captured by the camera through the two remaining open holes in the wheel. In this manner, near-infrared (NIR) and laser speckle images are captured and stored together in the computer for off-line processing to reconstruct the tissue's properties. Spatial patterns are used to differentiate the effects of tissue scattering from those of absorption, allowing accurate quantification of tissue hemodynamics and morphology, while a coherent light source is used to study blood flow changes, a feature which cannot be measured with the NIR structured light. This combined configuration utilizes the strengths of each system in a complementary way, thus collecting a larger range of sample properties. In addition, once the flow and hemodynamics are measured, tissue oxygen metabolism can be calculated, a property which cannot be measured independently. Therefore, this merged platform can be considered a multiparameter wide-field imaging and spectroscopy modality. Overall, experiments demonstrate the capability of this spatially coregistered imaging setup to provide complementary, useful information of various tissue metrics in a simple and noncontact manner, making it attractive for use in a variety of biomedical applications.
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Affiliation(s)
- Hadas Bloygrund
- Department of Electrical and Electronics Engineering, Ariel University, Ariel, Israel
| | - Yarden Franjy-Tal
- Department of Electrical and Electronics Engineering, Ariel University, Ariel, Israel
| | - Tovit Rosenzweig
- Department of Molecular Biology and Nutritional Studies, Ariel University, Ariel, Israel
| | - David Abookasis
- Department of Electrical and Electronics Engineering, Ariel University, Ariel, Israel
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20
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Shemesh D, Bokobza N, Rozenberg K, Rosenzweig T, Abookasis D. Decreased cerebral blood flow and hemodynamic parameters during acute hyperglycemia in mice model observed by dual-wavelength speckle imaging. JOURNAL OF BIOPHOTONICS 2019; 12:e201900002. [PMID: 30950209 DOI: 10.1002/jbio.201900002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Revised: 02/25/2019] [Accepted: 04/02/2019] [Indexed: 06/09/2023]
Abstract
In this study, we use dual-wavelength optical imaging-based laser speckle technique to assess cerebral blood flow and metabolic parameters in a mouse model of acute hyperglycemia (high blood glucose). The effect of acute glucose levels on physiological processes has been extensively described in multiple organ systems such as retina, kidney, and others. We postulated that hyperglycemia also alters brain function, which in turn can be monitored optically using dual-wavelength laser speckle imaging (DW-LSI) platform. DW-LSI is a wide-field, noncontact optical imaging modality that integrates the principles of laser flowmetry and oximetry to obtain macroscopic information such as hemoglobin concentration and blood flow. A total of eight mice (C57/BL6) were used, randomized into two groups of normoglycemia (control, n = 3) and hyperglycemia (n = 5). Hyperglycemia was induced by intraperitoneal injection of a commonly used anesthetic drug combining ketamine and xylazine (KX combo). We found that this KX combo increases blood glucose (BG) levels from 150 to 350 mg/dL, approximately, when measured 18 minutes post-administration. BG continues to increase throughout the test period, with BG reaching an average of 463 ± 20.34 mg/dL within 60 minutes. BG levels were measured every 10 minutes from tail blood using commercially available glucometer. Experimental results demonstrated reductions in cerebral blood flow (CBF) by 55%, tissue oxygen saturation (SO2 ) by 15%, and cerebral metabolic rate of oxygen (CMRO2 ) by 75% following acute hyperglycemia. The observed decrease in these parameters was consistent with results reported in the literature, measured by a variety of experimental techniques. Measurements with laser Doppler flowmetry (LDF) were also performed which confirmed a reduction in CBF following acute hyperglycemia. In summary, our findings indicate that acute hyperglycemia modified brain hemodynamic response and induced significant changes in blood flow and metabolism. As far as we are aware, the implementation of the DW-LSI to monitor brain hemodynamic and metabolic response to acute hyperglycemia in intact mouse brain has not been previously reported.
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Affiliation(s)
- David Shemesh
- Department of Electrical and Electronics Engineering, Ariel University, Ariel, Israel
| | - Naor Bokobza
- Department of Electrical and Electronics Engineering, Ariel University, Ariel, Israel
| | | | - Tovit Rosenzweig
- Department of Molecular Biology, Ariel University, Ariel, Israel
| | - David Abookasis
- Department of Electrical and Electronics Engineering, Ariel University, Ariel, Israel
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21
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Aguénounon E, Dadouche F, Uhring W, Gioux S. Real-time optical properties and oxygenation imaging using custom parallel processing in the spatial frequency domain. BIOMEDICAL OPTICS EXPRESS 2019; 10:3916-3928. [PMID: 31452984 PMCID: PMC6701546 DOI: 10.1364/boe.10.003916] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 06/06/2019] [Accepted: 06/11/2019] [Indexed: 05/03/2023]
Abstract
The development of real-time, wide-field and quantitative diffuse optical imaging methods is becoming increasingly popular for biological and medical applications. Recent developments introduced a novel approach for real-time multispectral acquisition in the spatial frequency domain using spatio-temporal modulation of light. Using this method, optical properties maps (absorption and reduced scattering) could be obtained for two wavelengths (665 nm and 860 nm). These maps, in turn, are used to deduce oxygen saturation levels in tissues. However, while the acquisition was performed in real-time, processing was performed post-acquisition and was not in real-time. In the present article, we present CPU and GPU processing implementations for this method with special emphasis on processing time. The obtained results show that the proposed custom direct method using a General Purpose Graphic Processing Unit (GPGPU) and C CUDA (Compute Unified Device Architecture) implementation enables 1.6 milliseconds processing time for a 1 Mega-pixel image with a maximum average error of 0.1% in extracting optical properties.
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Gioux S, Mazhar A, Cuccia DJ. Spatial frequency domain imaging in 2019: principles, applications, and perspectives. JOURNAL OF BIOMEDICAL OPTICS 2019; 24:1-18. [PMID: 31222987 PMCID: PMC6995958 DOI: 10.1117/1.jbo.24.7.071613] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 05/09/2019] [Indexed: 05/20/2023]
Abstract
Spatial frequency domain imaging (SFDI) has witnessed very rapid growth over the last decade, owing to its unique capabilities for imaging optical properties and chromophores over a large field-of-view and in a rapid manner. We provide a comprehensive review of the principles of this imaging method as of 2019, review the modeling of light propagation in this domain, describe acquisition methods, provide an understanding of the various implementations and their practical limitations, and finally review applications that have been published in the literature. Importantly, we also introduce a group effort by several key actors in the field for the dissemination of SFDI, including publications, advice in hardware and implementations, and processing code, all freely available online.
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Affiliation(s)
- Sylvain Gioux
- University of Strasbourg, ICube Laboratory, Strasbourg, France
- Address all correspondence to Sylvain Gioux, E-mail:
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23
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Kim S, Kim M, Kim JG. Development of simple diffuse optical metabolic spectroscopy for tissue metabolism measurement. BIOMEDICAL OPTICS EXPRESS 2019; 10:2956-2966. [PMID: 31259065 PMCID: PMC6583354 DOI: 10.1364/boe.10.002956] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 04/21/2019] [Accepted: 05/13/2019] [Indexed: 05/05/2023]
Abstract
In the field of biomedicine, there are optical systems that provide the tissue metabolic rate of oxygen consumption (tMRO2) by the simultaneous measurement of blood flow and oxygenation level. However, current optical systems are costly and require complex optical alignments, which are inconvenient for clinical applications. Therefore, in this study, we developed a simple diffuse optical metabolic spectroscopy system by combining a broadband light source and a laser and by sharing a spectrometer as a detector for both diffuse optical spectroscopy and diffuse speckle contrast analysis. This system simultaneously measures blood flow, volume, and oxygenation in a simple and cost-effective manner. The system response to flow is demonstrated through the flow phantom experiments. The results of the experiments show that flow response is in the range 0~0.9 ml/min, with a resolution better than 0.1 ml/min. During the blood phantom study, the blood volume fraction increased linearly with blood accumulation. Further, the change in oxygenation was monitored with the modulation of the oxygen level in the gas supply. Finally, tMRO2 changes were measured during ischemia, induced by the upper arm cuff and the results showed a decrease and a recovery of tMRO2 with cuff inflation and deflation, respectively. This simple diffuse optical metabolic spectroscopic system can easily be applied in medical environments by providing a simple and convenient solution for measuring tMRO2.
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Gioux S, Mazhar A, Cuccia DJ. Spatial frequency domain imaging in 2019: principles, applications, and perspectives. JOURNAL OF BIOMEDICAL OPTICS 2019. [PMID: 31222987 DOI: 10.1117/1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Spatial frequency domain imaging (SFDI) has witnessed very rapid growth over the last decade, owing to its unique capabilities for imaging optical properties and chromophores over a large field-of-view and in a rapid manner. We provide a comprehensive review of the principles of this imaging method as of 2019, review the modeling of light propagation in this domain, describe acquisition methods, provide an understanding of the various implementations and their practical limitations, and finally review applications that have been published in the literature. Importantly, we also introduce a group effort by several key actors in the field for the dissemination of SFDI, including publications, advice in hardware and implementations, and processing code, all freely available online.
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Affiliation(s)
- Sylvain Gioux
- University of Strasbourg, ICube Laboratory, Strasbourg, France
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25
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Aguénounon E, Dadouche F, Uhring W, Ducros N, Gioux S. Single snapshot imaging of optical properties using a single-pixel camera: a simulation study. JOURNAL OF BIOMEDICAL OPTICS 2019; 24:1-6. [PMID: 31037929 PMCID: PMC6995955 DOI: 10.1117/1.jbo.24.7.071612] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Accepted: 03/29/2019] [Indexed: 05/29/2023]
Abstract
We present the effects of using a single-pixel camera approach to extract optical properties with the single-snapshot spatial frequency-domain imaging method. We acquired images of a human hand for spatial frequencies ranging from 0.1 to 0.4 mm - 1 with increasing compression ratios using adaptive basis scan wavelet prediction strategy. In summary, our findings indicate that the extracted optical properties remained usable up to 99% of compression rate at a spatial frequency of 0.2 mm - 1 with errors of 5% in reduced scattering and 10% in absorption.
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Affiliation(s)
| | - Foudil Dadouche
- University of Strasbourg, ICube Laboratory, Illkirch, France
| | - Wilfried Uhring
- University of Strasbourg, ICube Laboratory, Illkirch, France
| | - Nicolas Ducros
- University Lyon, INSA Lyon, UCBL, CNRS 5220, INSERM U1206, CREATIS, Villeurbanne, France
| | - Sylvain Gioux
- University of Strasbourg, ICube Laboratory, Illkirch, France
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26
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Schmidt M, Aguénounon E, Nahas A, Torregrossa M, Tromberg BJ, Uhring W, Gioux S. Real-time, wide-field, and quantitative oxygenation imaging using spatiotemporal modulation of light. JOURNAL OF BIOMEDICAL OPTICS 2019; 24:1-7. [PMID: 30868804 PMCID: PMC6995963 DOI: 10.1117/1.jbo.24.7.071610] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Accepted: 01/28/2019] [Indexed: 05/07/2023]
Abstract
Quantitative diffuse optical imaging has the potential to provide valuable functional information about tissue status, such as oxygen saturation or blood content to healthcare practitioners in real time. However, significant technical challenges have so far prevented such tools from being deployed in the clinic. Toward achieving this goal, prior research introduced methods based on spatial frequency domain imaging (SFDI) that allow real-time (within milliseconds) wide-field imaging of optical properties but at a single wavelength. However, for this technology to be useful to clinicians, images must be displayed in terms of metrics related to the physiological state of the tissue, hence interpretable to guide decision-making. For this purpose, recent developments introduced multispectral SFDI methods for rapid imaging of oxygenation parameters up to 16 frames per seconds (fps). We introduce real-time, wide-field, and quantitative blood parameters imaging using spatiotemporal modulation of light. Using this method, we are able to quantitatively obtain optical properties at 100 fps at two wavelengths (665 and 860 nm), and therefore oxygenation, oxyhemoglobin, and deoxyhemoglobin, using a single camera with, at most, 4.2% error in comparison with standard SFDI acquisitions.
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Affiliation(s)
- Manon Schmidt
- University of Strasbourg, ICube Laboratory, Strasbourg, France
| | | | - Amir Nahas
- University of Strasbourg, ICube Laboratory, Strasbourg, France
| | | | - Bruce J. Tromberg
- Beckman Laser Institute and Medical Clinic, Laser Microbeam and Medical Program, Irvine, California, United States
- University of California, Department of Biomedical Engineering, Irvine, California, United States
| | - Wilfried Uhring
- University of Strasbourg, ICube Laboratory, Strasbourg, France
| | - Sylvain Gioux
- University of Strasbourg, ICube Laboratory, Strasbourg, France
- Address all correspondence to Sylvain Gioux, E-mail:
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27
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Aguénounon E, Dadouche F, Uhring W, Gioux S. Single snapshot of optical properties image quality improvement using anisotropic two-dimensional windows filtering. JOURNAL OF BIOMEDICAL OPTICS 2019; 24:1-21. [PMID: 30927346 PMCID: PMC6996016 DOI: 10.1117/1.jbo.24.7.071611] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 02/12/2019] [Indexed: 05/04/2023]
Abstract
Imaging methods permitting real-time, wide-field, and quantitative optical mapping of biological tissue properties offer an unprecedented range of applications for clinical use. Following the development of spatial frequency domain imaging, we introduce a real-time demodulation method called single snapshot of optical properties (SSOPs). However, since this method uses only a single image to generate absorption and reduced scattering maps, it was limited by a degraded image quality resulting in artifacts that diminished its potential for clinical use. We present filtering strategies for improving the image quality of optical properties maps obtained using SSOPs. We investigate the effect of anisotropic two-dimensional filtering strategies for spatial frequencies ranging from 0.1 to 0.4 mm - 1 directly onto N = 10 hands. Both accuracy and image quality of the optical properties are quantified in comparison with standard, multiple image acquisitions in the spatial frequency domain. Overall, using optimized filters, mean errors in predicting optical properties using SSOP remain under 8.8% in absorption and 7.5% in reduced scattering, while significantly improving image quality. Overall this work contributes to advance real-time, wide-field, and quantitative diffuse optical imaging toward clinical evaluation.
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Affiliation(s)
| | - Foudil Dadouche
- University of Strasbourg, ICube Laboratory, Illkirch, France
| | - Wilfried Uhring
- University of Strasbourg, ICube Laboratory, Illkirch, France
| | - Sylvain Gioux
- University of Strasbourg, ICube Laboratory, Illkirch, France
- Address all correspondence to Sylvain Gioux, E-mail:
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28
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Panigrahi S, Gioux S. Machine learning approach for rapid and accurate estimation of optical properties using spatial frequency domain imaging. JOURNAL OF BIOMEDICAL OPTICS 2018; 24:1-6. [PMID: 30550050 PMCID: PMC6995874 DOI: 10.1117/1.jbo.24.7.071606] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 10/16/2018] [Indexed: 05/03/2023]
Abstract
Fast estimation of optical properties from reflectance measurements at two spatial frequencies could pave way for real-time, wide-field and quantitative mapping of vital signs of tissues. We present a machine learning-based approach for estimating optical properties in the spatial frequency domain, where a random forest regression algorithm is trained over data obtained from Monte-Carlo photon transport simulations. The algorithm learns the nonlinear mapping between diffuse reflectance at two spatial frequencies, and the absorption and reduced scattering coefficient of the tissue under consideration. Using this method, absorption and reduced scattering properties could be obtained over a 1 megapixel image in 450 ms with errors as low as 0.556% in absorption and 0.126% in reduced scattering.
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Affiliation(s)
| | - Sylvain Gioux
- University of Strasbourg, ICube Laboratory, Strasbourg, France
- Address all correspondence to: Sylvain Gioux, E-mail:
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29
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Ghijsen M, Rice TB, Yang B, White SM, Tromberg BJ. Wearable speckle plethysmography (SPG) for characterizing microvascular flow and resistance. BIOMEDICAL OPTICS EXPRESS 2018; 9:3937-3952. [PMID: 30338166 PMCID: PMC6191642 DOI: 10.1364/boe.9.003937] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 07/11/2018] [Accepted: 07/18/2018] [Indexed: 05/04/2023]
Abstract
In this work we introduce a modified form of laser speckle imaging (LSI) referred to as affixed transmission speckle analysis (ATSA) that uses a single coherent light source to probe two physiological signals: one related to pulsatile vascular expansion (classically known as the photoplethysmographic (PPG) waveform) and one related to pulsatile vascular blood flow (named here the speckle plethysmographic (SPG) waveform). The PPG signal is determined by recording intensity fluctuations, and the SPG signal is determined via the LSI dynamic light scattering technique. These two co-registered signals are obtained by transilluminating a single digit (e.g. finger) which produces quasi-periodic waveforms derived from the cardiac cycle. Because PPG and SPG waveforms probe vascular expansion and flow, respectively, in cm-thick tissue, these complementary phenomena are offset in time and have rich dynamic features. We characterize the timing offset and harmonic content of the waveforms in 16 human subjects and demonstrate physiologic relevance for assessing microvascular flow and resistance.
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Affiliation(s)
- Michael Ghijsen
- Laser Microbeam and Medical Program, Beckman Laser Institute, 1002 Health Sciences Road, Irvine, CA 92612, USA
- Department of Biomedical Engineering, University of California, Irvine, CA 92697, USA
| | - Tyler B. Rice
- Laser Associated Sciences Inc., 16 Foxglove Way, Irvine, CA 92612, USA
| | - Bruce Yang
- Laser Associated Sciences Inc., 16 Foxglove Way, Irvine, CA 92612, USA
| | - Sean M. White
- Laser Associated Sciences Inc., 16 Foxglove Way, Irvine, CA 92612, USA
| | - Bruce J. Tromberg
- Laser Microbeam and Medical Program, Beckman Laser Institute, 1002 Health Sciences Road, Irvine, CA 92612, USA
- Department of Biomedical Engineering, University of California, Irvine, CA 92697, USA
- Department of Surgery, University of California, Irvine Medical Center, Orange, CA 92868, USA
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