Spatial distribution and relationship of T and T2 relaxation times in knee cartilage with osteoarthritis

Authors

  • Xiaojuan Li,

    Corresponding author
    1. Musculoskeletal Quantitative Imaging Research (MQIR) Group, Department of Radiology, University of California, San Francisco, San Francisco, California, USA
    • Department of Radiology, University of California at San Francisco, 185 Berry Street, Suite 350, San Francisco, CA 94107
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  • Alex Pai,

    1. Department of Electrical Engineering and Computer Science, University of California, Berkeley, Berkeley, California, USA
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  • Gabrielle Blumenkrantz,

    1. Department of Electrical Engineering and Computer Science, University of California, Berkeley, Berkeley, California, USA
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  • Julio Carballido-Gamio,

    1. Musculoskeletal Quantitative Imaging Research (MQIR) Group, Department of Radiology, University of California, San Francisco, San Francisco, California, USA
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  • Thomas Link,

    1. Musculoskeletal Quantitative Imaging Research (MQIR) Group, Department of Radiology, University of California, San Francisco, San Francisco, California, USA
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  • Benjamin Ma,

    1. Department of Orthopaedic Surgery, University of California, San Francisco, San Francisco, California, USA
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  • Michael Ries,

    1. Department of Orthopaedic Surgery, University of California, San Francisco, San Francisco, California, USA
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  • Sharmila Majumdar

    1. Musculoskeletal Quantitative Imaging Research (MQIR) Group, Department of Radiology, University of California, San Francisco, San Francisco, California, USA
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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.

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