Relationship between cartilage stiffness and dGEMRIC index: correlation and prediction

Area of Science:

• Biomedical Engineering
• Orthopedics
• Radiology

Background:

• Articular cartilage health is crucial for joint function.
• Assessing cartilage mechanical properties non-invasively is important for diagnosing joint diseases.
• The dGEMRIC index (T1Gd relaxation time) shows promise for evaluating cartilage.

Purpose of the Study:

• To establish a generalized relationship between the dGEMRIC index and articular cartilage compressive stiffness.
• To investigate if this relationship varies across different cartilage regions and sample sources.

Main Methods:

• Osteochondral blocks from 12 human tibial plateaus were analyzed.
• Pulse indentation measured local cartilage stiffness.
• dGEMRIC MRI determined the dGEMRIC index at multiple sites per block.

Main Results:

• No correlation was found between stiffness and full cartilage depth dGEMRIC index.
• Good correlations emerged when dGEMRIC index was averaged over indentation depth.
• Predictive accuracy improved by analyzing covered and uncovered regions separately and by using dGEMRIC index differences.

Conclusions:

• The dGEMRIC index is highly correlated with articular cartilage mechanical stiffness.
• A generalized relationship exists, providing good correspondence across various samples and regions.
• The dGEMRIC index can be a valuable predictive measure of cartilage stiffness, with accuracy dependent on application needs.