title: Imaging of subchondral bone by optical coherence tomography upon optical clearing of articular cartilage.
abstract: Optical clearing is an effective method to reduce light scattering of biological tissues that provides significant enhancement of light penetration into the biological tissues making non-invasive diagnosis more feasible. In current report Optical Coherence Tomography (OCT) in conjunction with optical clearing is applied for assessment of deep cartilage layers and cartilage-bone interface. The solution of Iohexol in water has been used as an optical clearing agent. The cartilage-bone boundary becomes visible after 15 min of optical clearing that enabling non-invasive estimation of its roughness: Sa = 10 ± 1 µm. The results show that for 0.9 mm thick cartilage optical clearing is stopped after 50 min with an increase of refractive index from 1.386 ± 0.008 to 1.510 ± 0.009. Current approach enables more reliable detection of arthroscopically inaccessible regions, including cartilage-bone boundary and subchondral bone, and potentially improves accuracy of the osteoarthritis diagnosis.
authors.affiliation: Optoelectronics and Measurement Techniques Laboratory, University of Oulu, P.O. Box 4500, 90014, Oulu, Finland. bykov@ee.oulu.fi.|ITMO University, 49 Kronverksky pr., Saint-Petersburg, 197101, Russia. bykov@ee.oulu.fi.|Interdisciplinary Laboratory of Biophotonics, Tomsk State University, Tomsk, 634050, Russia. bykov@ee.oulu.fi.
authors.forename: Alexander
authors.initials: A
authors.lastname: Bykov
authors.affiliation: Optoelectronics and Measurement Techniques Laboratory, University of Oulu, P.O. Box 4500, 90014, Oulu, Finland.
authors.forename: Tapio
authors.initials: T
authors.lastname: Hautala
authors.affiliation: Optoelectronics and Measurement Techniques Laboratory, University of Oulu, P.O. Box 4500, 90014, Oulu, Finland.
authors.forename: Matti
authors.initials: M
authors.lastname: Kinnunen
authors.affiliation: Optoelectronics and Measurement Techniques Laboratory, University of Oulu, P.O. Box 4500, 90014, Oulu, Finland.|ITMO University, 49 Kronverksky pr., Saint-Petersburg, 197101, Russia.|Interdisciplinary Laboratory of Biophotonics, Tomsk State University, Tomsk, 634050, Russia.
authors.forename: Alexey
authors.initials: A
authors.lastname: Popov
authors.affiliation: Department of Medical Technology, Institute of Biomedicine, University of Oulu, P.O. Box 5000, 90014, Oulu, Finland.|Medical Research Center, University of Oulu and Oulu University Hospital, P.O. Box 50, 90029, Oulu, Finland.
authors.forename: Sakari
authors.initials: S
authors.lastname: Karhula
authors.affiliation: Department of Medical Technology, Institute of Biomedicine, University of Oulu, P.O. Box 5000, 90014, Oulu, Finland.|Medical Research Center, University of Oulu and Oulu University Hospital, P.O. Box 50, 90029, Oulu, Finland.|Department of Diagnostic Radiology, Oulu University Hospital, P.O. Box 50, 90029, Oulu, Finland.
authors.forename: Simo
authors.initials: S
authors.lastname: Saarakkala
authors.affiliation: Medical Research Center, University of Oulu and Oulu University Hospital, P.O. Box 50, 90029, Oulu, Finland.|Department of Diagnostic Radiology, Oulu University Hospital, P.O. Box 50, 90029, Oulu, Finland.|Department of Radiology, University of Oulu, P.O. Box 5000, 90014, Oulu, Finland.
authors.forename: Miika T
authors.initials: MT
authors.lastname: Nieminen
authors.affiliation: Optoelectronics and Measurement Techniques Laboratory, University of Oulu, P.O. Box 4500, 90014, Oulu, Finland.|Research-Educational Institute of Optics and Biophotonics, Saratov State University, 410012, Saratov, Russia.|Institute of Precise Mechanics and Control of Russian Academy of Sciences, Russian Academy of Sciences, 410028, Saratov, Russia.
authors.forename: Valery
authors.initials: V
authors.lastname: Tuchin
authors.affiliation: Optoelectronics and Measurement Techniques Laboratory, University of Oulu, P.O. Box 4500, 90014, Oulu, Finland.|ITMO University, 49 Kronverksky pr., Saint-Petersburg, 197101, Russia.|Interdisciplinary Laboratory of Biophotonics, Tomsk State University, Tomsk, 634050, Russia.
authors.forename: Igor
authors.initials: I
authors.lastname: Meglinski
mesh_terms: D000818:Animals; D001842:Bone and Bones; D002358:Cartilage, Articular; D002417:Cattle; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D055620:Optical Phenomena; D012542:Scattering, Radiation; D041623:Tomography, Optical Coherence / Q000379:methods*
keywords: Optical Coherence Tomography (OCT); articular cartilage; optical clearing; osteoarthritis; subchondral bone