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Keywords:

  • osteoarthritis;
  • cartilage;
  • magnetic resonance imaging;
  • T (T1rho);
  • T2.;
  • texture analysis

Abstract

T and T2 relaxation time constants have been proposed to probe biochemical changes in osteoarthritic cartilage. This study aimed to evaluate the spatial correlation and distribution of T and T2 values in osteoarthritic cartilage. Ten patients with osteoarthritis (OA) and 10 controls were studied at 3T. The spatial correlation of T and T2 values was investigated using Z-scores. The spatial variation of T and T2 values in patellar cartilage was studied in different cartilage layers. The distribution of these relaxation time constants was measured using texture analysis parameters based on gray-level co-occurrence matrices (GLCM). The mean Z-scores for T and T2 values were significantly higher in OA patients vs. controls (P < 0.05). Regional correlation coefficients of T and T2Z-scores showed a large range in both controls and OA patients (0.2–0.7). OA patients had significantly greater GLCM contrast and entropy of T values than controls (P < 0.05). In summary, T and T2 values are not only increased but are also more heterogeneous in osteoarthritic cartilage. T and T2 values show different spatial distributions and may provide complementary information regarding cartilage degeneration in OA. Magn Reson Med, 2009. © 2009 Wiley-Liss, Inc.