Osteoarthritis in rhesus macaques: assessment of cartilage matrix quality by quantitative magnetic resonance imaging.

To assess cartilage quality with anatomical location and extent of osteoarthritis (OA), magnetic resonance imaging (MRI) of the knee joint from rhesus monkeys was performed. MRI measurements--T1 and T2 relaxation times, proton density and cartilage thickness were taken from 8 equal segments of articular cartilage volumes extending from anterior to posterior edge of 1 mm sagittal slices. To grade the severity of OA in each quadrant of the knee joint a modified Mankin score was applied on the histological sections. Our results suggest that MR relaxation times and proton density values vary with the severity of osteoarthritis.