The compositional difference between ankle and knee cartilage demonstrated by T2 mapping at 7 Tesla MR

Area of Science:

• Biomedical Engineering
• Radiology
• Orthopedics

Background:

• Cartilage T2 relaxation times reflect tissue composition and integrity.
• Previous studies suggest biochemical and biomechanical differences between knee and ankle cartilage.
• Non-invasive in vivo assessment of cartilage properties is crucial for understanding joint health.

Purpose of the Study:

• To systematically compare T2 relaxation times of knee and ankle cartilage within the same subjects.
• To investigate in vivo cartilage properties using high-field magnetic resonance imaging (MRI).
• To establish a baseline for future research on cartilage degeneration and repair.

Main Methods:

• Ten healthy volunteers underwent 7 Tesla MRI scans.
• A three-dimensional triple-echo steady state (3D-TESS) sequence was utilized.
• Analysis of variance (ANOVA) was employed to compare T2 values across seven cartilage compartments.

Main Results:

• Patellar and femoral cartilage in the knee showed significantly higher T2 values (25.8 ± 1.2 ms and 24.9 ± 1.3 ms, respectively) compared to tibial and talar cartilage.
• Tibial cartilage T2 values were 19.2 ± 1 ms, and talar cartilage T2 values were 18.1 ± 0.6 ms.
• No significant differences in T2 values were found between the medial and lateral ankle cartilage facets (p>0.05).

Conclusions:

• This study provides the first systematic, within-subject comparison of knee and ankle cartilage T2 values in vivo.
• The findings support previous evidence of distinct biochemical and biomechanical properties between knee and ankle cartilage.
• High-field MRI offers a valuable tool for non-invasively assessing in vivo cartilage characteristics.