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Qi X, Bertling K, Torniainen J, Kong F, Gillespie T, Primiero C, Stark MS, Dean P, Indjin D, Li LH, Linfield EH, Davies AG, Brünig M, Mills T, Rosendahl C, Soyer HP, Rakić AD. Terahertz in vivo imaging of human skin: Toward detection of abnormal skin pathologies. APL Bioeng 2024; 8:016117. [PMID: 38476403 PMCID: PMC10932572 DOI: 10.1063/5.0190573] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Accepted: 02/19/2024] [Indexed: 03/14/2024] Open
Abstract
Terahertz (THz) imaging has long held promise for skin cancer detection but has been hampered by the lack of practical technological implementation. In this article, we introduce a technique for discriminating several skin pathologies using a coherent THz confocal system based on a THz quantum cascade laser. High resolution in vivo THz images (with diffraction limited to the order of 100 μm) of several different lesion types were acquired and compared against one another using the amplitude and phase values. Our system successfully separated pathologies using a combination of phase and amplitude information and their respective surface textures. The large scan field (50 × 40 mm) of the system allows macroscopic visualization of several skin lesions in a single frame. Utilizing THz imaging for dermatological assessment of skin lesions offers substantial additional diagnostic value for clinicians. THz images contain information complementary to the information contained in the conventional digital images.
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Affiliation(s)
- X. Qi
- School of Electrical Engineering and Computer Science, The University of Queensland, Brisbane QLD 4072, Australia
| | - K. Bertling
- School of Electrical Engineering and Computer Science, The University of Queensland, Brisbane QLD 4072, Australia
| | - J. Torniainen
- School of Electrical Engineering and Computer Science, The University of Queensland, Brisbane QLD 4072, Australia
| | - F. Kong
- Dermatology Research Centre, Frazer Institute, The University of Queensland, Woolloongabba QLD 4102, Australia
| | - T. Gillespie
- School of Electrical Engineering and Computer Science, The University of Queensland, Brisbane QLD 4072, Australia
| | - C. Primiero
- Dermatology Research Centre, Frazer Institute, The University of Queensland, Woolloongabba QLD 4102, Australia
| | - M. S. Stark
- Dermatology Research Centre, Frazer Institute, The University of Queensland, Woolloongabba QLD 4102, Australia
| | - P. Dean
- School of Electronic and Electrical Engineering, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - D. Indjin
- School of Electronic and Electrical Engineering, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - L. H. Li
- School of Electronic and Electrical Engineering, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - E. H. Linfield
- School of Electronic and Electrical Engineering, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - A. G. Davies
- School of Electronic and Electrical Engineering, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - M. Brünig
- School of Electrical Engineering and Computer Science, The University of Queensland, Brisbane QLD 4072, Australia
| | - T. Mills
- OscillaDx Pty Ltd, Brisbane, Queensland, Australia
| | - C. Rosendahl
- General Practice Clinical Unit, Faculty of Medicinee, The University of Queensland, Herston QLD 4029, Australia
| | - H. P. Soyer
- Dermatology Research Centre, Frazer Institute, The University of Queensland, Woolloongabba QLD 4102, Australia
| | - A. D. Rakić
- School of Electrical Engineering and Computer Science, The University of Queensland, Brisbane QLD 4072, Australia
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Sarin JK, Te Moller NCR, Mohammadi A, Prakash M, Torniainen J, Brommer H, Nippolainen E, Shaikh R, Mäkelä JTA, Korhonen RK, van Weeren PR, Afara IO, Töyräs J. Machine learning augmented near-infrared spectroscopy: In vivo follow-up of cartilage defects. Osteoarthritis Cartilage 2021; 29:423-432. [PMID: 33359249 DOI: 10.1016/j.joca.2020.12.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 11/06/2020] [Accepted: 12/11/2020] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To assess the potential of near-infrared spectroscopy (NIRS) for in vivo arthroscopic monitoring of cartilage defects. METHOD Sharp and blunt cartilage grooves were induced in the radiocarpal and intercarpal joints of Shetland ponies and monitored at baseline (0 weeks) and at three follow-up timepoints (11, 23, and 39 weeks) by measuring near-infrared spectra in vivo at and around the grooves. The animals were sacrificed after 39 weeks and the joints were harvested. Spectra were reacquired ex vivo to ensure reliability of in vivo measurements and for reference analyses. Additionally, cartilage thickness and instantaneous modulus were determined via computed tomography and mechanical testing, respectively. The relationship between the ex vivo spectra and cartilage reference properties was determined using convolutional neural network. RESULTS In an independent test set, the trained networks yielded significant correlations for cartilage thickness (ρ = 0.473) and instantaneous modulus (ρ = 0.498). These networks were used to predict the reference properties at baseline and at follow-up time points. In the radiocarpal joint, cartilage thickness increased significantly with both groove types after baseline and remained swollen. Additionally, at 39 weeks, a significant difference was observed in cartilage thickness between controls and sharp grooves. For the instantaneous modulus, a significant decrease was observed with both groove types in the radiocarpal joint from baseline to 23 and 39 weeks. CONCLUSION NIRS combined with machine learning enabled determination of cartilage properties in vivo, thereby providing longitudinal evaluation of post-intervention injury development. Additionally, radiocarpal joints were found more vulnerable to cartilage degeneration after damage than intercarpal joints.
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Affiliation(s)
- J K Sarin
- Department of Applied Physics, University of Eastern Finland, Kuopio, Finland; Diagnostic Imaging Center, Kuopio University Hospital, Kuopio, Finland.
| | - N C R Te Moller
- Department of Clinical Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands.
| | - A Mohammadi
- Department of Applied Physics, University of Eastern Finland, Kuopio, Finland.
| | - M Prakash
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland.
| | - J Torniainen
- Department of Applied Physics, University of Eastern Finland, Kuopio, Finland; Diagnostic Imaging Center, Kuopio University Hospital, Kuopio, Finland.
| | - H Brommer
- Department of Clinical Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands.
| | - E Nippolainen
- Department of Applied Physics, University of Eastern Finland, Kuopio, Finland.
| | - R Shaikh
- Department of Applied Physics, University of Eastern Finland, Kuopio, Finland.
| | - J T A Mäkelä
- Department of Applied Physics, University of Eastern Finland, Kuopio, Finland.
| | - R K Korhonen
- Department of Applied Physics, University of Eastern Finland, Kuopio, Finland.
| | - P R van Weeren
- Department of Clinical Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands; Regenerative Medicine Utrecht, Utrecht, the Netherlands.
| | - I O Afara
- Department of Applied Physics, University of Eastern Finland, Kuopio, Finland.
| | - J Töyräs
- Department of Applied Physics, University of Eastern Finland, Kuopio, Finland; Diagnostic Imaging Center, Kuopio University Hospital, Kuopio, Finland; School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane, Australia.
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Ristaniemi A, Torniainen J, Stenroth L, Finnilä M, Paakkonen T, Töyräs J, Korhonen R. Comparison of water, hydroxyproline, uronic acid and elastin contents of bovine knee ligaments and patellar tendon and their relationships with biomechanical properties. J Mech Behav Biomed Mater 2020; 104:103639. [DOI: 10.1016/j.jmbbm.2020.103639] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 01/13/2020] [Accepted: 01/13/2020] [Indexed: 12/13/2022]
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Prakash M, Joukainen A, Torniainen J, Honkanen MKM, Rieppo L, Afara IO, Kröger H, Töyräs J, Sarin JK. Near-infrared spectroscopy enables quantitative evaluation of human cartilage biomechanical properties during arthroscopy. Osteoarthritis Cartilage 2019; 27:1235-1243. [PMID: 31026649 DOI: 10.1016/j.joca.2019.04.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 02/11/2019] [Accepted: 04/09/2019] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To investigate the feasibility of near-infrared (NIR) spectroscopy (NIRS) for evaluation of human articular cartilage biomechanical properties during arthroscopy. DESIGN A novel arthroscopic NIRS probe designed in our research group was utilized by an experienced orthopedic surgeon to measure NIR spectra from articular cartilage of human cadaver knee joints (ex vivo, n = 18) at several measurement locations during an arthroscopic surgery. Osteochondral samples (n = 265) were extracted from the measurement sites for reference analysis. NIR spectra were remeasured in a controlled laboratory environment (in vitro), after which the corresponding cartilage thickness and biomechanical properties were determined. Hybrid multivariate regression models based on principal component analysis and linear mixed effects modeling (PCA-LME) were utilized to relate cartilage in vitro spectra and biomechanical properties, as well as to account for the spatial dependency. Additionally, a k-nearest neighbors (kNN) classifier was employed to reject outlying ex vivo NIR spectra resulting from a non-optimal probe-cartilage contact. Model performance was evaluated for both in vitro and ex vivo NIR spectra via Spearman's rank correlation (ρ) and the ratio of performance to interquartile range (RPIQ). RESULTS Regression models accurately predicted cartilage thickness and biomechanical properties from in vitro NIR spectra (Model: 0.77 ≤ ρ ≤ 0.87, 2.03 ≤ RPIQ ≤ 3.0; Validation: 0.74 ≤ ρ ≤ 0.84, 1.87 ≤ RPIQ ≤ 2.90). When predicting cartilage properties from ex vivo NIR spectra (0.33 ≤ ρ ≤ 0.57 and 1.02 ≤ RPIQ ≤ 2.14), a kNN classifier enhanced the accuracy of predictions (0.52 ≤ ρ ≤ 0.87 and 1.06 ≤ RPIQ ≤ 1.88). CONCLUSION Arthroscopic NIRS could substantially enhance identification of damaged cartilage by enabling quantitative evaluation of cartilage biomechanical properties. The results demonstrate the capacity of NIRS in clinical applications.
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Affiliation(s)
- M Prakash
- Department of Applied Physics, University of Eastern Finland, Finland; Diagnostic Imaging Center, Kuopio University Hospital, Kuopio, Finland.
| | - A Joukainen
- Department of Orthopedics, Traumatology and Hand Surgery, Kuopio University Hospital, Kuopio, Finland.
| | - J Torniainen
- Department of Applied Physics, University of Eastern Finland, Finland; Diagnostic Imaging Center, Kuopio University Hospital, Kuopio, Finland.
| | - M K M Honkanen
- Department of Applied Physics, University of Eastern Finland, Finland; Diagnostic Imaging Center, Kuopio University Hospital, Kuopio, Finland.
| | - L Rieppo
- Department of Applied Physics, University of Eastern Finland, Finland; Research Unit of Medical Imaging, Physics and Technology, Faculty of Medicine, University of Oulu, Oulu, Finland.
| | - I O Afara
- Department of Applied Physics, University of Eastern Finland, Finland.
| | - H Kröger
- Department of Orthopedics, Traumatology and Hand Surgery, Kuopio University Hospital, Kuopio, Finland.
| | - J Töyräs
- Department of Applied Physics, University of Eastern Finland, Finland; Diagnostic Imaging Center, Kuopio University Hospital, Kuopio, Finland; School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane, Australia.
| | - J K Sarin
- Department of Applied Physics, University of Eastern Finland, Finland; Diagnostic Imaging Center, Kuopio University Hospital, Kuopio, Finland.
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Torniainen J, Kainz MJ, Jones RI, Keinänen M, Vuorinen PJ, Kiljunen M. Influence of the marine feeding area on the muscle and egg fatty-acid composition of Atlantic salmon Salmo salar spawners estimated from the scale stable isotopes. J Fish Biol 2017; 90:1717-1733. [PMID: 28101948 DOI: 10.1111/jfb.13258] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Accepted: 11/30/2016] [Indexed: 06/06/2023]
Abstract
Fatty acids in muscle tissue and eggs of female Atlantic salmon Salmo salar spawners were analysed to evaluate the dietary quality of their final feeding areas in the Baltic Sea. The final likely feeding area was identified by comparing stable carbon and nitrogen isotope composition of the outermost growth region (final annulus) of scales of returned S. salar with that of reference S. salar caught from different feeding areas. Some overlap of stable-isotope reference values among the three areas, in addition to prespawning fasting, decreased the ability of muscle tri-acylglycerols to discriminate the final likely feeding area and the area's dietary quality. Among three long-chained polyunsaturated fatty acids, docosahexaenoic acid (DHA; 22:6n-3), eicosapentaenoic acid (EPA; 20:5n-3) and arachidonic acid (ARA; 20:4n-6), the proportions of ARA in total lipids of spawning S. salar muscle and eggs showed a significant negative correlation with increasing probability of S. salar having returned from the Baltic Sea main basin (i.e. the Baltic Sea proper). The results suggest that ARA in muscle and eggs is the best dietary indicator for dietary characteristics of final marine feeding area dietary characteristics among S. salar in the Baltic Sea.
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Affiliation(s)
- J Torniainen
- University of Jyvaskyla, Department of Biological and Environmental Science, P. O. Box 35, FI-40014, Jyvaskyla, Finland
- University of Jyvaskyla, Natural History Museum, P. O. Box 35, FI-40014, Jyvaskyla, Finland
| | - M J Kainz
- WasserCluster - Biologische Station Lunz, A-3293, Lunz am See, Austria
| | - R I Jones
- University of Jyvaskyla, Department of Biological and Environmental Science, P. O. Box 35, FI-40014, Jyvaskyla, Finland
| | - M Keinänen
- Natural Resources Institute Finland (Luke), P. O. Box 2, FI-00791, Helsinki, Finland
| | - P J Vuorinen
- Natural Resources Institute Finland (Luke), P. O. Box 2, FI-00791, Helsinki, Finland
| | - M Kiljunen
- University of Jyvaskyla, Department of Biological and Environmental Science, P. O. Box 35, FI-40014, Jyvaskyla, Finland
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