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Jonasson H, Fredriksson I, Bergstrand S, Östgren CJ, Larsson M, Strömberg T. Absorption and reduced scattering coefficients in epidermis and dermis from a Swedish cohort study. JOURNAL OF BIOMEDICAL OPTICS 2023; 28:115001. [PMID: 38078153 PMCID: PMC10704088 DOI: 10.1117/1.jbo.28.11.115001] [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: 07/10/2023] [Revised: 09/25/2023] [Accepted: 10/30/2023] [Indexed: 12/18/2023]
Abstract
Significance Knowledge of optical properties is important to accurately model light propagation in tissue, but in vivo reference data are sparse. Aim The aim of our study was to present in vivo skin optical properties from a large Swedish cohort including 3809 subjects using a three-layered skin model and spatially resolved diffuse reflectance spectroscopy (Periflux PF6000 EPOS). Approach Diffuse reflectance spectra (475 to 850 nm) at 0.4 and 1.2 mm source-detector separations were analyzed using an inverse Monte Carlo method. The model had one epidermis layer with variable thicknesses and melanin-related absorptions and two dermis layers with varying hemoglobin concentrations and equal oxygen saturations. The reduced scattering coefficient was equal across all layers. Results Median absorption coefficients (mm - 1 ) in the upper dermis ranged from 0.094 at 475 nm to 0.0048 at 850 nm and similarly in the lower dermis from 0.059 to 0.0035. The reduced scattering coefficient (mm - 1 ) ranged from 3.22 to 1.20, and the sampling depth (mm) ranged from 0.23 to 0.38 (0.4 mm separation) and from 0.49 to 0.68 (1.2 mm separation). There were differences in optical properties across sex, age groups, and BMI categories. Conclusions Reference material for skin optical properties is presented.
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Affiliation(s)
- Hanna Jonasson
- Linköping University, Department of Biomedical Engineering, Linköping, Sweden
| | - Ingemar Fredriksson
- Linköping University, Department of Biomedical Engineering, Linköping, Sweden
- Perimed AB, Järfälla, Stockholm, Sweden
| | - Sara Bergstrand
- Linköping University, Department of Health, Medicine, and Caring Sciences, Linköping, Sweden
| | - Carl Johan Östgren
- Linköping University, Department of Health, Medicine, and Caring Sciences, Linköping, Sweden
- Linköping University, Centre of Medical Image Science and Visualization Linköping, Sweden
| | - Marcus Larsson
- Linköping University, Department of Biomedical Engineering, Linköping, Sweden
| | - Tomas Strömberg
- Linköping University, Department of Biomedical Engineering, Linköping, Sweden
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2
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Samils L, Henricson J, Strömberg T, Fredriksson I, Iredahl F. Workload and sex effects in comprehensive assessment of cutaneous microcirculation. Microvasc Res 2023; 148:104547. [PMID: 37192688 DOI: 10.1016/j.mvr.2023.104547] [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: 03/29/2023] [Revised: 04/25/2023] [Accepted: 05/11/2023] [Indexed: 05/18/2023]
Abstract
INTRODUCTION Workload and sex-related differences have been proposed as factors of importance when evaluating the microcirculation. Simultaneous assessments with diffuse reflectance spectroscopy (DRS) and laser Doppler flowmetry (LDF) enable a comprehensive evaluation of the microcirculation. The aim of the study was to compare the response between sexes in the microcirculatory parameters red blood cell (RBC) tissue fraction, RBC oxygen saturation, average vessel diameter, and speed-resolved perfusion during baseline, cycling, and recovery, respectively. METHODS In 24 healthy participants (aged 20 to 30 years, 12 females), cutaneous microcirculation was assessed by LDF and DRS at baseline, during a workload generated by cycling at 75 to 80 % of maximal age-predicted heart rate, and recovery, respectively. RESULTS Females had significantly lower RBC tissue fraction and total perfusion in forearm skin microcirculation at all phases (baseline, workload, and recovery). All microvascular parameters increased significantly during cycling, most evident in RBC oxygen saturation (34 % increase on average) and perfusion (9-fold increase in total perfusion). For perfusion, the highest speeds (>10 mm/s) increased by a factor of 31, whereas the lowest speeds (<1 mm/s) increased by a factor of 2. CONCLUSION Compared to a resting state, all studied microcirculation measures increased during cycling. For perfusion, this was mainly due to increased speed, and only to a minor extent due to increased RBC tissue fraction. Skin microcirculatory differences between sexes were seen in RBC concentration and total perfusion.
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Affiliation(s)
- Linda Samils
- Department of Health, Medicine and Caring Sciences, Division of Community Medicine, Linköping University, Linköping, Sweden
| | - Joakim Henricson
- Department of Emergency Medicine in Linköping, Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
| | - Tomas Strömberg
- Department of Biomedical Engineering, Linköping University, Linköping, Sweden
| | - Ingemar Fredriksson
- Department of Biomedical Engineering, Linköping University, Linköping, Sweden
| | - Fredrik Iredahl
- Department of Health, Medicine and Caring Sciences, Division of Community Medicine, Linköping University, Linköping, Sweden.
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Caratenuto A, Li S, Wan Y, Zheng Y. Optical Epidermal Mimicry from Ultraviolet to Infrared Wavelengths. ACS APPLIED BIO MATERIALS 2022; 5:5231-5239. [PMID: 36331184 DOI: 10.1021/acsabm.2c00660] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Optical tissue phantoms present substantial value for medical imaging and therapeutic applications. We have developed an epidermal tissue phantom to mimic the optical properties of human skin from the ultraviolet to the infrared region, exceeding the breadth of existing studies. An epoxy matrix is combined with melanin-mimicking polydopamine via a cost-effective fabrication strategy. Reflectance and transmittance measurements enable calculation of the wavelength-dependent complex refractive index and absorption coefficient. Results are compared with literature data to establish agreement with a real human epidermis. By analyzing emissive power at a typical skin temperature, the epidermal tissue phantom is shown to accurately mimic the radiative properties of human skin. This simple, multifunctional material represents a promising substitute for human tissue for a variety of medical and bioengineering applications.
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Affiliation(s)
- Andrew Caratenuto
- Department of Mechanical and Industrial Engineering, Northeastern University, Boston, Massachusetts02115, United States
| | - Su Li
- Department of Mechanical and Industrial Engineering, Northeastern University, Boston, Massachusetts02115, United States
| | - Yinsheng Wan
- Department of Biology, Providence College, Providence, Rhode Island02918, United States
| | - Yi Zheng
- Department of Mechanical and Industrial Engineering, Northeastern University, Boston, Massachusetts02115, United States.,Department of Chemical Engineering, Northeastern University, Boston, Massachusetts02115, United States
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Ma KF, Kleiss SF, Schuurmann RCL, Nijboer TS, El Moumni M, Bokkers RPH, de Vries JPPM. Laser Doppler Flowmetry Combined with Spectroscopy to Determine Peripheral Tissue Perfusion and Oxygen Saturation: A Pilot Study in Healthy Volunteers and Patients with Peripheral Arterial Disease. J Pers Med 2022; 12:jpm12060853. [PMID: 35743638 PMCID: PMC9224808 DOI: 10.3390/jpm12060853] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Accepted: 05/20/2022] [Indexed: 12/27/2022] Open
Abstract
Background: In this study, we assessed the ability of the EPOS system (Perimed AB, Järfälla, Stockholm, Sweden) to detect differences in tissue perfusion between healthy volunteers and patients with peripheral arterial disease (PAD) with different severity of disease. Methods: This single-center prospective pilot study included 10 healthy volunteers and 20 patients with PAD scheduled for endovascular therapy (EVT). EPOS measurements were performed at rest at 32 °C and 44 °C, followed by transcutaneous oxygen pressure (TcPo2) measurements. The measurements were performed on the dorsal and medial side of the foot, as well as the lateral side of the calf. EPOS parameters included hemoglobin oxygen saturation (HbSo2) and speed-resolved red blood cell (RBC) perfusion. Results: HbSo2 at 44 °C was significantly different between the three groups for all measurement locations. The overall speed-resolved RBC perfusion at 44 °C was statistically significant between the groups on the dorsal and medial side of the foot but not on the calf. TcPo2 values were not significantly different between the three groups. Conclusions: This study demonstrates that the EPOS system can depict differences in tissue perfusion between healthy volunteers, patients with Fontaine class IIb PAD, and those with Fontaine class III or IV PAD but only after heating to 44 °C.
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Affiliation(s)
- Kirsten F. Ma
- Division of Vascular Surgery, Department of Surgery, University of Groningen, University Medical Center Groningen, 9713 GZ Groningen, The Netherlands; (S.F.K.); (R.C.L.S.); (T.S.N.); (J.-P.P.M.d.V.)
- Correspondence:
| | - Simone F. Kleiss
- Division of Vascular Surgery, Department of Surgery, University of Groningen, University Medical Center Groningen, 9713 GZ Groningen, The Netherlands; (S.F.K.); (R.C.L.S.); (T.S.N.); (J.-P.P.M.d.V.)
| | - Richte C. L. Schuurmann
- Division of Vascular Surgery, Department of Surgery, University of Groningen, University Medical Center Groningen, 9713 GZ Groningen, The Netherlands; (S.F.K.); (R.C.L.S.); (T.S.N.); (J.-P.P.M.d.V.)
| | - Thomas S. Nijboer
- Division of Vascular Surgery, Department of Surgery, University of Groningen, University Medical Center Groningen, 9713 GZ Groningen, The Netherlands; (S.F.K.); (R.C.L.S.); (T.S.N.); (J.-P.P.M.d.V.)
| | - Mostafa El Moumni
- Division of Trauma Surgery, Department of Surgery, University of Groningen, University Medical Center Groningen, 9713 GZ Groningen, The Netherlands;
| | - Reinoud P. H. Bokkers
- Department of Radiology, Medical Imaging Center, University of Groningen, University Medical Center Groningen, 9713 GZ Groningen, The Netherlands;
| | - Jean-Paul P. M. de Vries
- Division of Vascular Surgery, Department of Surgery, University of Groningen, University Medical Center Groningen, 9713 GZ Groningen, The Netherlands; (S.F.K.); (R.C.L.S.); (T.S.N.); (J.-P.P.M.d.V.)
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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: 4] [Impact Index Per Article: 2.0] [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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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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Jonasson H, Bergstrand S, Fredriksson I, Larsson M, Östgren CJ, Strömberg T. Post-ischemic skin peak oxygen saturation is associated with cardiovascular risk factors: a Swedish cohort study. Microvasc Res 2021; 140:104284. [PMID: 34826433 DOI: 10.1016/j.mvr.2021.104284] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 11/17/2021] [Accepted: 11/17/2021] [Indexed: 02/08/2023]
Abstract
The objective of this study was to explore the associations between skin microcirculatory function and established cardiovascular risk factors in a large Swedish cohort. As part of the Swedish CArdioPulmonary bioImage Study (SCAPIS), microcirculatory data were acquired at Linköping University hospital, Linköping, Sweden during 2016-2017. The subjects, aged 50-64 years, were randomly selected from the national population register. Microcirculatory reactivity was assessed using a 5-min arterial occlusion-release protocol. Comprehensive skin microcirculatory data were continuously acquired by using a fiberoptic probe placed on the lower right arm. After exclusion of missing data (208), 1557 subjects were remaining. Among the parameters, skin microcirculatory peak oxygen saturation after occlusion release, had the strongest relationship to the cardiovascular risk factors. The linear associations between peak oxygen saturation and cardiovascular risk factors were analyzed adjusted for age and sex. We found a negative association with peak oxygen saturation (standardized regression coefficient) for blood pressure (systolic -0.05 (95% CI: -0.10;-0.003) and diastolic -0.05 (-0.10; -0.003)), BMI -0.18 (-0.23; -0.13), waist circumference (males -0.20 (-0.32; -0.16), females -0.18 (-0.25; -0.11)), prevalent diabetes -0.31 (-0.49; -0.12), hypertension -0.30 (-0.42; -0.18), dyslipidemia -0.24 (-0.40; -0.09), fasting glucose level -0.06 (-0.12; -0.01), HbA1c -0.07 (-0.12; -0.02), triglyceride level -0.09 (-0.14; -0.04), hsCRP -0.12 (-0.17; -0.07), and current smoker versus never smoked -0.50 (-0.67; -0.34). A positive association with peak oxygen saturation was found for cholesterol level 0.05 (0.005; 0.11) and HDL 0.11 (0.06; 0.17). This is the first study showing that post-ischemic skin microvascular peak oxygen saturation is associated with virtually all established cardiovascular risk factors in a population-based middle-aged cohort.
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Affiliation(s)
- Hanna Jonasson
- Department of Biomedical Engineering, Linköping University, Linköping, Sweden.
| | - Sara Bergstrand
- Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden
| | - Ingemar Fredriksson
- Department of Biomedical Engineering, Linköping University, Linköping, Sweden; Perimed AB, Järfälla, Stockholm, Sweden
| | - Marcus Larsson
- Department of Biomedical Engineering, Linköping University, Linköping, Sweden
| | - Carl Johan Östgren
- Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden
| | - Tomas Strömberg
- Department of Biomedical Engineering, Linköping University, Linköping, Sweden
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Fredriksson I, Larsson M, Strömberg T, Iredahl F. Vasomotion analysis of speed resolved perfusion, oxygen saturation, red blood cell tissue fraction, and vessel diameter: Novel microvascular perspectives. Skin Res Technol 2021; 28:142-152. [PMID: 34758168 PMCID: PMC9907591 DOI: 10.1111/srt.13106] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 08/21/2021] [Indexed: 12/17/2022]
Abstract
BACKGROUND Vasomotion is the spontaneous oscillation in vascular tone in the microcirculation and is believed to be a physiological mechanism facilitating the transport of blood gases and nutrients to and from tissues. So far, Laser Doppler flowmetry has constituted the gold standard for in vivo vasomotion analysis. MATERIALS AND METHODS We applied vasomotion analysis to speed-resolved perfusion, oxygen saturation, red blood cell tissue (RBC) tissue fraction, and average vessel diameter from five healthy individuals at rest measured by the newly developed Periflux 6000 EPOS system over 10 minutes. Magnitude scalogram and the time-averaged wavelet spectra were divided into frequency intervals reflecting endothelial, neurogenic, myogenic, respiratory, and cardiac function. RESULTS Recurrent high-intensity periods of the myogenic, neurogenic, and endothelial frequency intervals were found. The neurogenic activity was considerably more pronounced for the oxygen saturation, RBC tissue fraction, and vessel diameter signals, than for the perfusion signals. In a correlation analysis we found that changes in perfusion in the myogenic, neurogenic, and endothelial frequency intervals precede changes in the other signals. Furthermore, changes in average vessel diameter were in general negatively correlated to the other signals in the same frequency intervals, indicating the importance of capillary recruitment. CONCLUSION We conclude that vasomotion can be observed in signals reflecting speed resolved perfusion, oxygen saturation, RBC tissue fraction, and vessel diameter. The new parameters enable new aspects of the microcirculation to be observed.
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Affiliation(s)
- Ingemar Fredriksson
- Department of Biomedical Engineering, Linköping University, Linköping, Sweden
| | - Marcus Larsson
- Department of Biomedical Engineering, Linköping University, Linköping, Sweden
| | - Tomas Strömberg
- Department of Biomedical Engineering, Linköping University, Linköping, Sweden
| | - Fredrik Iredahl
- Department of Health, Medicine and Caring Sciences, Linköping University, Division of Community Medicine, Linköping, Sweden.,Department of Primary health care, Region Östergötland, Linköping, Sweden
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Goldfain AM, Lemaillet P, Allen DW, Briggman KA, Hwang J. Polydimethylsiloxane tissue-mimicking phantoms with tunable optical properties. JOURNAL OF BIOMEDICAL OPTICS 2021; 27:JBO-210209SSRR. [PMID: 34796707 PMCID: PMC8601433 DOI: 10.1117/1.jbo.27.7.074706] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 10/25/2021] [Indexed: 05/05/2023]
Abstract
SIGNIFICANCE The polymer, polydimethylsiloxane (PDMS), has been increasingly used to make tissue simulating phantoms due to its excellent processability, durability, flexibility, and limited tunability of optical, mechanical, and thermal properties. We report on a robust technique to fabricate PDMS-based tissue-mimicking phantoms where the broad range of scattering and absorption properties are independently adjustable in the visible- to near-infrared wavelength range from 500 to 850 nm. We also report on an analysis method to concisely quantify the phantoms' broadband characteristics with four parameters. AIM We report on techniques to manufacture and characterize solid tissue-mimicking phantoms of PDMS polymers. Tunability of the absorption (μa ( λ ) ) and reduced scattering coefficient spectra (μs'(λ)) in the wavelength range of 500 to 850 nm is demonstrated by adjusting the concentrations of light absorbing carbon black powder (CBP) and light scattering titanium dioxide powder (TDP) added into the PDMS base material. APPROACH The μa ( λ ) and μs'(λ) of the phantoms were obtained through measurements with a broadband integrating sphere system and by applying an inverse adding doubling algorithm. Analyses of μa ( λ ) and μs'(λ) of the phantoms, by fitting them to linear and power law functions, respectively, demonstrate that independent control of μa ( λ ) and μs'(λ) is possible by systematically varying the concentrations of CBP and TDP. RESULTS Our technique quantifies the phantoms with four simple fitting parameters enabling a concise tabulation of their broadband optical properties as well as comparisons to the optical properties of biological tissues. We demonstrate that, to a limited extent, the scattering properties of our phantoms mimic those of human tissues of various types. A possible way to overcome this limitation is demonstrated with phantoms that incorporate polystyrene microbead scatterers. CONCLUSIONS Our manufacturing and analysis techniques may further promote the application of PDMS-based tissue-mimicking phantoms and may enable robust quality control and quality checks of the phantoms.
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Affiliation(s)
- Aaron M. Goldfain
- National Institute of Standards and Technology, Sensor Science Division, Gaithersburg, Maryland, United States
| | - Paul Lemaillet
- National Institute of Standards and Technology, Sensor Science Division, Gaithersburg, Maryland, United States
| | - David W. Allen
- National Institute of Standards and Technology, Sensor Science Division, Gaithersburg, Maryland, United States
| | - Kimberly A. Briggman
- National Institute of Standards and Technology, Applied Physics Division, Boulder, Colorado, United States
| | - Jeeseong Hwang
- National Institute of Standards and Technology, Applied Physics Division, Boulder, Colorado, United States
- Address all correspondence to Jeeseong Hwang,
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Ewerlöf M, Salerud EG, Strömberg T, Larsson M. Estimation of skin microcirculatory hemoglobin oxygen saturation and red blood cell tissue fraction using a multispectral snapshot imaging system: a validation study. JOURNAL OF BIOMEDICAL OPTICS 2021; 26:JBO-200291RR. [PMID: 33583154 PMCID: PMC7881095 DOI: 10.1117/1.jbo.26.2.026002] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 01/13/2021] [Indexed: 05/08/2023]
Abstract
SIGNIFICANCE Hemoglobin oxygen saturation and red blood cell (RBC) tissue fraction are important parameters when assessing microvascular status. Functional information can be attained using temporally resolved measurements performed during stimulus-response protocols. Pointwise assessments can currently be conducted with probe-based systems. However, snapshot multispectral imaging (MSI) can be used for spatial-temporal measurements. AIM To validate if hemoglobin oxygen saturation and RBC tissue fraction can be quantified using a snapshot MSI system and an inverse Monte Carlo algorithm. APPROACH Skin tissue measurements from the MSI system were compared to those from a validated probe-based system during arterial and venous occlusion provocation on 24 subjects in the wavelength interval 450 to 650 nm, to evaluate a wide range of hemoglobin oxygen saturation and RBC tissue fraction levels. RESULTS Arterial occlusion results show a mean linear regression R2 = 0.958 for hemoglobin oxygen saturation. Comparing relative RBC tissue fraction during venous occlusion results in R2 = 0.925. The MSI system shows larger dynamic changes than the reference system, which might be explained by a deeper sampling including more capacitance vessels. CONCLUSIONS The snapshot MSI system estimates hemoglobin oxygen saturation and RBC tissue fraction in skin microcirculation showing a high correlation (R2 > 0.9 in most subjects) with those measured by the reference method.
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Affiliation(s)
- Maria Ewerlöf
- Linköping University, Department of Biomedical Engineering, Linköping, Sweden
| | - E. Göran Salerud
- 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
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11
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Fredriksson I, Larsson M, Strömberg T. Machine learning for direct oxygen saturation and hemoglobin concentration assessment using diffuse reflectance spectroscopy. JOURNAL OF BIOMEDICAL OPTICS 2020; 25:JBO-200177SSR. [PMID: 33205635 PMCID: PMC7670094 DOI: 10.1117/1.jbo.25.11.112905] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 10/28/2020] [Indexed: 05/13/2023]
Abstract
SIGNIFICANCE Diffuse reflectance spectroscopy (DRS) is frequently used to assess oxygen saturation and hemoglobin concentration in living tissue. Methods solving the inverse problem may include time-consuming nonlinear optimization or artificial neural networks (ANN) determining the absorption coefficient one wavelength at a time. AIM To present an ANN-based method that directly outputs the oxygen saturation and the hemoglobin concentration using the shape of the measured spectra as input. APPROACH A probe-based DRS setup with dual source-detector separations in the visible wavelength range was used. ANNs were trained on spectra generated from a three-layer tissue model with oxygen saturation and hemoglobin concentration as target. RESULTS Modeled evaluation data with realistic measurement noise showed an absolute root-mean-square (RMS) deviation of 5.1% units for oxygen saturation estimation. The relative RMS deviation for hemoglobin concentration was 13%. This accuracy is at least twice as good as our previous nonlinear optimization method. On blood-intralipid phantoms, the RMS deviation from the oxygen saturation derived from partial oxygen pressure measurements was 5.3% and 1.6% in two separate measurement series. Results during brachial occlusion showed expected patterns. CONCLUSIONS The presented method, directly assessing oxygen saturation and hemoglobin concentration, is fast, accurate, and robust to noise.
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Affiliation(s)
- Ingemar Fredriksson
- Linköping University, Department of Biomedical Engineering, Linköping, Sweden
- Perimed AB, Stockholm, Sweden
- Address all correspondence to Ingemar Fredriksson,
| | - Marcus Larsson
- Linköping University, Department of Biomedical Engineering, Linköping, Sweden
| | - Tomas Strömberg
- Linköping University, Department of Biomedical Engineering, Linköping, Sweden
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12
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Bergkvist M, Henricson J, Bergstrand S, Strömberg T, Tesselaar E, Farnebo S. Assessment of oxygenation with polarized light spectroscopy enables new means for detecting vascular events in the skin. Microvasc Res 2020; 130:104000. [PMID: 32194082 DOI: 10.1016/j.mvr.2020.104000] [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: 09/01/2019] [Revised: 03/12/2020] [Accepted: 03/12/2020] [Indexed: 11/17/2022]
Abstract
INTRODUCTION Impaired oxygenation in the skin may occur in disease states and after reconstructive surgery. We used tissue viability imaging (TiVi) to measure changes in oxygenation and deoxygenation of haemoglobin in an in vitro model and in the dermal microcirculation of healthy individuals. MATERIALS AND METHODS Oxygenation was measured in human whole blood with different levels of oxygenation. In healthy subjects, changes in red blood cell concentration (CRBC,TiVi), oxygenation (ΔCOH,TiVi) and deoxygenation (ΔCDOH,TiVi) of haemoglobin were measured during and after arterial and venous occlusion using TiVi and were compared with measurements from the enhanced perfusion and oxygen saturation system (EPOS). RESULTS During arterial occlusion, CRBC,TiVi remained unchanged while ΔCOH,TiVi decreased to -44.2 (10.4) AU (p = 0.04), as compared to baseline. After release, CRBC,TiVi increased to 39.2 (18.8) AU (p < 0.001), ΔCOH,TiVi increased to 38.5. During venous occlusion, CRBC,TiVi increased to 28.9 (11.2) AU (p < 0.001), ΔCOH,TiVi decreased to -52.2 (46.1) AU (p < 0.001) compared to baseline after 5 min of venous occlusion. There was a significant correlation between the TiVi Oxygen Mapper and EPOS, for arterial (r = 0.92, p < 0.001) and venous occlusion (r = 0.87, p < 0.001), respectively. CONCLUSION This study shows that TiVi can measure trends in oxygenation and deoxygenation of haemoglobin during arterial and venous stasis in healthy individuals.
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Affiliation(s)
- Max Bergkvist
- Department of Hand Surgery, Plastic Surgery and Burns, Linköping University, Linköping, Sweden; Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden.
| | - Joakim Henricson
- Department of Biomedical and Clinical Sciences, Linköping University, Sweden; Departement of Emergency Medicine, Local Health Care Services in Central Östergötland, Linköping, Östergötland, Sweden
| | - Sara Bergstrand
- Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
| | - Tomas Strömberg
- Department of Biomedical Engineering, Linköping University, Linköping, Sweden
| | - Erik Tesselaar
- Department of Medical Radiation Physics, Linköping University, Linköping, Sweden; Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden
| | - Simon Farnebo
- Department of Hand Surgery, Plastic Surgery and Burns, Linköping University, Linköping, Sweden; Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden
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13
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Wang G, Jia S, Liu M, Song X, Li H, Chang X, Zhang W. Impact of local thermal stimulation on the correlation between oxygen saturation and speed-resolved blood perfusion. Sci Rep 2020; 10:183. [PMID: 31932611 PMCID: PMC6957488 DOI: 10.1038/s41598-019-57067-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 12/18/2019] [Indexed: 11/23/2022] Open
Abstract
The physiologically important relationship between oxygen saturation and blood flow is not entirely understood, particularly with regard to the multiple velocity components of flow and temperature. While our previous studies used classic laser Doppler flowmetry combined with an enhanced perfusion probe to assess local blood flow following thermal stimulation, oxygen saturation signals were not assessed. Thus, the current study used multiscale entropy (MSE) and multiscale fuzzy entropy (MFE) to measure the complexity of oxygen saturation signals following thermal stimulation in healthy subjects. The results indicate that thermal stimulation increases oxygen saturation and affects the measured signal complexity in a temperature-dependent fashion. Furthermore, stimulus temperature not only affects the correlation between speed-resolved blood perfusion and oxygen saturation, but also the correlation between the complexity area indices (CAI) of the two signals. These results reflect the complexity of local regulation and adaptation processes in response to stimuli at different temperatures.
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Affiliation(s)
- Guangjun Wang
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, China.
| | - Shuyong Jia
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, China
| | - Mi Liu
- Acupuncture and Tuina School, Hunan University of Chinese Medicine, Changsha, China
| | - Xiaojing Song
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, China
| | - Hongyan Li
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, China
| | - Xiaorong Chang
- Acupuncture and Tuina School, Hunan University of Chinese Medicine, Changsha, China.
| | - Weibo Zhang
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, China.
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Jonasson H, Fredriksson I, Larsson M, Strömberg T. Validation of speed-resolved laser Doppler perfusion in a multimodal optical system using a blood-flow phantom. JOURNAL OF BIOMEDICAL OPTICS 2019; 24:1-8. [PMID: 31512441 PMCID: PMC6997578 DOI: 10.1117/1.jbo.24.9.095002] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 08/14/2019] [Indexed: 05/24/2023]
Abstract
The PeriFlux 6000 EPOS system combines diffuse reflectance spectroscopy (DRS) and laser Doppler flowmetry (LDF) for the assessment of oxygen saturation (expressed in percentage), red blood cell (RBC) tissue fraction (expressed as volume fraction, %RBC), and perfusion (%RBC × mm / s) in the microcirculation. It also allows the possibility of separating the perfusion into three speed regions (0 to 1, 1 to 10, and >10 mm / s). We evaluate the speed-resolved perfusion components, i.e., the relative amount of perfusion within each speed region, using a blood-flow phantom. Human blood was pumped through microtubes with an inner diameter of 0.15 mm. Measured DRS and LDF spectra were compared to Monte Carlo-simulated spectra in an optimization routine, giving the best-fit parameters describing the measured spectra. The root-mean-square error for each of the three speed components (0 to 1, 1 to 10, and >10 mm / s, respectively) when describing the blood-flow speed in the microtubes was 2.9%, 8.1%, and 7.7%. The presented results show that the system can accurately discriminate blood perfusion originating from different blood-flow speeds, which may enable improved measurement of healthy and dysfunctional microcirculatory flow.
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Affiliation(s)
- Hanna Jonasson
- Linköping University, Department of Biomedical Engineering, Linköping, Sweden
| | - Ingemar Fredriksson
- Linköping University, Department of Biomedical Engineering, Linköping, Sweden
- Perimed AB, Järfälla, Stockholm, Sweden
| | - Marcus Larsson
- Linköping University, Department of Biomedical Engineering, Linköping, Sweden
| | - Tomas Strömberg
- Linköping University, Department of Biomedical Engineering, Linköping, Sweden
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15
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Saager RB, Rowland RA, Baldado ML, Kennedy GT, Bernal NP, Ponticorvo A, Christy RJ, Durkin AJ. Impact of hemoglobin breakdown products in the spectral analysis of burn wounds using spatial frequency domain spectroscopy. JOURNAL OF BIOMEDICAL OPTICS 2019; 24:1-4. [PMID: 30724041 PMCID: PMC6398280 DOI: 10.1117/1.jbo.24.2.020501] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 01/15/2019] [Indexed: 05/23/2023]
Abstract
Burn wounds and wound healing invoke several biological processes that may complicate the interpretation of spectral imaging data. Through analysis of spatial frequency domain spectroscopy data (450 to 1000 nm) obtained from longitudinal investigations using a graded porcine burn wound healing model, we have identified features in the absorption spectrum that appear to suggest the presence of hemoglobin breakdown products, e.g., methemoglobin. Our results show that the calculated concentrations of methemoglobin directly correlate with burn severity, 24 h after the injury. In addition, tissue parameters such as oxygenation (StO2) and water fraction may be underestimated by 20% and 78%, respectively, if methemoglobin is not included in the spectral analysis.
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Affiliation(s)
- Rolf B Saager
- University of California Irvine, Beckman Laser Institute and Medical Clinic, Irvine, California, United States
| | - Rebecca A Rowland
- University of California Irvine, Beckman Laser Institute and Medical Clinic, Irvine, California, United States
| | - Melissa L Baldado
- University of California Irvine, Beckman Laser Institute and Medical Clinic, Irvine, California, United States
| | - Gordon T Kennedy
- University of California Irvine, Beckman Laser Institute and Medical Clinic, Irvine, California, United States
| | - Nicole P Bernal
- UC Irvine Regional Burn Center, Department of Surgery, Orange, California, United States
| | - Adrien Ponticorvo
- University of California Irvine, Beckman Laser Institute and Medical Clinic, Irvine, California, United States
| | - Robert J Christy
- United States Army Institute of Surgical Research, Burn and Soft Tissue Injury, San Antonio, Texas, United States
| | - Anthony J Durkin
- 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
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16
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Horan ST, Gardner AR, Saager R, Durkin AJ, Venugopalan V. Recovery of layered tissue optical properties from spatial frequency-domain spectroscopy and a deterministic radiative transport solver. JOURNAL OF BIOMEDICAL OPTICS 2018; 24:1-11. [PMID: 30456934 PMCID: PMC6995875 DOI: 10.1117/1.jbo.24.7.071607] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 10/12/2018] [Indexed: 05/26/2023]
Abstract
We present a method to recover absorption and reduced scattering spectra for each layer of a two-layer turbid media from spatial frequency-domain spectroscopy data. We focus on systems in which the thickness of the top layer is less than the transport mean free path ( 0.1 - 0.8l * ) . We utilize an analytic forward solver, based upon the N'th-order spherical harmonic expansion with Fourier decomposition ( SHEFN ) method in conjunction with a multistage inverse solver. We test our method with data obtained using spatial frequency-domain spectroscopy with 32 evenly spaced wavelengths within λ = 450 to 1000 nm on six-layered tissue phantoms with distinct optical properties. We demonstrate that this approach can recover absorption and reduced scattering coefficient spectra for both layers with accuracy comparable with current Monte Carlo methods but with lower computational cost and potential flexibility to easily handle variations in parameters such as the scattering phase function or material refractive index. To our knowledge, this approach utilizes the most accurate deterministic forward solver used in such problems and can successfully recover properties from a two-layer media with superficial layer thicknesses.
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Affiliation(s)
- Sean T. Horan
- University of California, Department of Mathematics, Irvine, California, United States
- University of California, Beckman Laser Institute, Laser Microbeam and Medical Program, Irvine, California, United States
| | - Adam R. Gardner
- University of California, Beckman Laser Institute, Laser Microbeam and Medical Program, Irvine, California, United States
- University of California, Department of Chemical Engineering and Materials Science, Irvine, California, United States
| | - Rolf Saager
- University of California, Beckman Laser Institute, Laser Microbeam and Medical Program, Irvine, California, United States
- Linköping University, Department of Biomedical Engineering, Linköping, Sweden
| | - Anthony J. Durkin
- University of California, Beckman Laser Institute, Laser Microbeam and Medical Program, Irvine, California, United States
- University of California, Department of Biomedical Engineering, Irvine, California, United States
| | - Vasan Venugopalan
- University of California, Beckman Laser Institute, Laser Microbeam and Medical Program, Irvine, California, United States
- University of California, Department of Chemical Engineering and Materials Science, Irvine, California, United States
- University of California, Department of Biomedical Engineering, Irvine, California, United States
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17
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Jonasson H, Fredriksson I, Bergstrand S, Östgren CJ, Larsson M, Strömberg T. In vivo characterization of light scattering properties of human skin in the 475- to 850-nm wavelength range in a Swedish cohort. JOURNAL OF BIOMEDICAL OPTICS 2018; 23:1-6. [PMID: 30267487 DOI: 10.1117/1.jbo.23.12.121608] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 08/31/2018] [Indexed: 05/04/2023]
Abstract
We have determined in vivo optical scattering properties of normal human skin in 1734 subjects, mostly with fair skin type, within the Swedish CArdioPulmonary bioImage Study. The measurements were performed with a noninvasive system, integrating spatially resolved diffuse reflectance spectroscopy and laser Doppler flowmetry. Data were analyzed with an inverse Monte Carlo algorithm, accounting for both scattering, geometrical, and absorbing properties of the tissue. The reduced scattering coefficient was found to decrease from 3.16 ± 0.72 to 1.13 ± 0.27 mm-1 (mean ± SD) in the 475- to 850-nm wavelength range. There was a negative correlation between the reduced scattering coefficient and age, and a significant difference between men and women in the reduced scattering coefficient as well as in the fraction of small scattering particles. This large study on tissue scattering with mean values and normal variation can serve as a reference when designing diagnostic techniques or when evaluating the effect of therapeutic optical systems.
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Affiliation(s)
- Hanna Jonasson
- Linköping University, Department of Biomedical Engineering, Linköping, Sweden
- Linköping University, Department of Medical and Health Sciences, Linköping, Sweden
| | - Ingemar Fredriksson
- Linköping University, Department of Biomedical Engineering, Linköping, Sweden
- Perimed AB, Järfälla, Stockholm, Sweden
| | - Sara Bergstrand
- Linköping University, Department of Medical and Health Sciences, Linköping, Sweden
| | - Carl Johan Östgren
- Linköping University, Department of Medical and Health Sciences, Linköping, Sweden
| | - Marcus Larsson
- Linköping University, Department of Biomedical Engineering, Linköping, Sweden
| | - Tomas Strömberg
- Linköping University, Department of Biomedical Engineering, Linköping, Sweden
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18
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Liu G, Wu Q, Dwivedi P, Hu C, Zhu Z, Shen S, Chu J, Zhao G, Si T, Xu R. Hemoglobin-Laden Microcapsules for Simulating Oxygen Dynamics of Biological Tissue. ACS Biomater Sci Eng 2018; 4:3177-3184. [DOI: 10.1021/acsbiomaterials.8b00830] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Guangli Liu
- Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Huangshan Road, Hefei, Anhui 230027, China
| | - Qiang Wu
- Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Huangshan Road, Hefei, Anhui 230027, China
| | - Pankaj Dwivedi
- Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Huangshan Road, Hefei, Anhui 230027, China
| | - Chuanzhen Hu
- Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Huangshan Road, Hefei, Anhui 230027, China
| | - Zhiqiang Zhu
- Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Huangshan Road, Hefei, Anhui 230027, China
| | - Shuwei Shen
- Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Huangshan Road, Hefei, Anhui 230027, China
| | - Jiaru Chu
- Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Huangshan Road, Hefei, Anhui 230027, China
| | - Gang Zhao
- Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Huangshan Road, Hefei, Anhui 230027, China
| | - Ting Si
- Department of Modern Mechanics, University of Science and Technology of China, Huangshan Road, Hefei, Anhui 230027, China
| | - Ronald Xu
- Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Huangshan Road, Hefei, Anhui 230027, China
- Department of Biomedical Engineering, The Ohio State University, 1080 Carmack Road, Columbus, Ohio 43210, United States
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