Research Unit of Medical Imaging, Physics and Technology, Faculty of Medicine, University of Oulu, Oulu, Finland; Department of Regenerative Medicine, State Research Institute, Centre for Innovative Medicine, Santariskiu 5, LT-08406 Vilnius, Lithuania; University Medical Center Utrecht, Departments of Orthopedics, Rheumatology & Clinical Immunology, 508 GA Utrecht, the Netherlands; Centre for Sport, Exercise and Osteoarthritis Versus Arthritis, Queen's Medical Centre, Nottingham, United Kingdom; Corresponding author at: Research Unit of Medical Imaging, Physics and Technology, Faculty of Medicine, University of Oulu, Oulu, Finland.