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.