OBJECTIVES: We compare the T1 and
T2 relaxation times and
magnetization transfer ratios (MTRs) of normal subjects and patients with
osteoarthritis (OA) to evaluate the ability of these techniques to aid in the early diagnosis and treatment of OA. MATERIALS AND METHODS: The
knee joints in 11 normal volunteers and 40 patients with OA were prospectively evaluated using
T1 relaxation times as measured using delayed gadolinium-enhanced
MRI of
cartilage (dGEMRIC),
T2 relaxation times (multiple spin-echo sequence, T2 mapping), and MTRs. The OA patients were further categorized into mild, moderate, and severe OA. RESULTS: The
mean T1 relaxation times of the four groups (normal, mild OA, moderate OA, and severe OA) were: 487.3 +/- 27.7, 458.0 +/- 55.9, 405.9 +/- 57.3, and 357.9 +/- 36.7 respectively (p <0.001). The
mean T2 relaxation times of the four groups were: 37.8 +/- 3.3, 44.0 +/- 8.5, 50.9 +/- 9.5, and 57.4 +/- 4.8 respectively (p < 0.001).
T1 relaxation time decreased and
T2 relaxation time increased with worsening degeneration of patellar
cartilage. The result of the
covariance analysis showed that the
covariate age had a significant influence on
T2 relaxation time (p < 0.001). No significant differences between the normal and OA groups using MTR were noted. CONCLUSION: T1 and
T2 relaxation times are relatively sensitive to early degenerative changes in the patellar
cartilage, whereas the MTR may have some limitations with regard to early detection of OA. In addition, The T1 and
T2 relaxation times negatively
correlate with each other, which is a novel finding.
