Functional MRI Mapping of Human Meniscus Functionality and its Relation to Degeneration

Area of Science:

• Biomedical Engineering
• Radiology
• Orthopedics

Background:

• Meniscus pathology is linked to early osteoarthritis development.
• Understanding meniscus functionality under load is crucial for diagnosing degeneration.
• Quantitative MRI offers potential for non-invasive assessment of tissue properties.

Purpose of the Study:

• To assess ex vivo human meniscus functionality using quantitative MRI (T1, T1ρ, T2 mapping).
• To correlate MRI findings with histological degeneration and biomechanical properties under controlled loading.
• To identify MRI parameters sensitive to meniscus degeneration and loading response.

Main Methods:

• Harvested 45 lateral meniscus samples from total knee arthroplasties.
• Performed serial MRI mapping (3.0-T) under unloaded, 2-bar, and 4-bar compression.
• Correlated MRI data with histology (Pauli classification) and Elastic Modulus.
• Analyzed samples categorized as intact, mildly degenerative, and moderate-to-severely degenerative.

Main Results:

• T1 mapping showed loading-induced decreases in all samples.
• T1ρ mapping revealed zonal increases in intact samples (apex) and decreases in degenerative samples (base).
• T2 mapping showed ambiguous changes; T1 and T1ρ were not clearly related to degeneration, but T1ρ patterns were promising.

Conclusions:

• Force-controlled loading and serial MRI can reveal meniscus response-to-loading patterns.
• Zonal T1ρ response-to-loading patterns show potential for differentiating meniscus degeneration.
• Quantitative MRI may provide an imaging-based indication of functional meniscus tissue properties.