Estimating the severity of osteoarthritis with magnetic resonance spectroscopy.

This study explores the possibility of estimating the severity of osteoarthritis in the elderly through magnetic resonance measurements of proton relaxation times in articular cartilage. Twenty-five paired samples were cut from eight cartilage specimens. The specimens had been taken in the normal course of knee surgery from patients aged 60 years or older. The reciprocal of the T1 relaxation time (1/T1) was found to have a negative association with the histological-histochemical grade of the severity of osteoarthritis. A revised, weighted version of the Mankin-Dorfman severity scale yielded stronger correlations with 1/T1 and with percent water. A nonlinear regression equation expressing osteoarthritis as a function of 1/T1 explained 38% of the variation in the severity of osteoarthritis as measured by the new scale. A superior methodology for estimating the severity of osteoarthritis on the basis of contour maps of the magnetic resonance response is suggested.