Timo Liimatainen1, Mikko Nissi2,3, Miika T. Nieminen4,5, Shalom Michaeli6, Michael Garwood6, Olli Grhn7
1Department of Biotechnology and Molecular Medicine, University of Kuopio, Kuopio, Finland; 2Department of Physics, University of Kuopio, Kuopio, Finland; 3Department of Clinical Radiology, Kuopio University Hospital, Kuopio, Finland; 4Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland; 5Department of Medical Technology, University of Oulu, Oulu, Finland; 6Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States; 7Department of Neurobiology, University of Kuopio, Kuopio, Finland
Possibility of measuring the physicochemical properties of cartilage proteoglycans could help diagnosis and monitoring of osteoarthritis. Relaxation along a fictitious field (RAFF) was optimized to detect proton exchange between water and proteoglycans (OH groups), and its applicability for cartilage imaging was studied using Bloch-McConnell simulations and cartilage samples. Relaxation measurements with optimized RAFF provided better CNRs between deep and intermediate and between deep and superficial cartilage than continuous wave T1ρ corresponding to increasing proteoglycan content towards bone. The RAFF rate constant is suggested as a potential biomarker for cartilage degeneration, also for in vivo imaging.