Imaging of articular cartilage: current concepts

Area of Science:

• Orthopedics
• Radiology
• Biomedical Engineering

Background:

• Magnetic resonance imaging (MRI) is the gold standard for non-invasive joint cartilage assessment.
• MRI provides crucial information on cartilage structure, morphology, and molecular composition.

Purpose of the Study:

• To outline the minimum requirements for effective cartilage MRI.
• To discuss advanced MRI techniques for assessing cartilage biochemistry and integrity.
• To review MRI classifications for joint degeneration and cartilage repair.

Main Methods:

• Utilizing high-field MRI (≥ 1.5 Tesla) with surface coils.
• Employing specific sequences like T2-weighted, proton density-weighted fast-spin echo (T2 FSE-DP), and 3D fat-suppressed T1-weighted gradient echo (3D-FS T1W GRE).
• Incorporating MR arthrography for enhanced visualization of articular surface defects and repair tissue interface integrity.
• Applying advanced techniques such as dGEMRIC, T1rho mapping, sodium (23Na) imaging, T2 mapping, magnetization transfer contrast, and diffusion-weighted imaging (DWI) for biochemical assessment.

Main Results:

• Specific MRI protocols and sequences are necessary for accurate cartilage evaluation.
• MR arthrography improves the detection of subtle cartilage lesions and assesses repair tissue integration.
• Various quantitative MRI techniques enable detailed biochemical analysis of cartilage and repair tissues.
• Established MRI classifications (WORMS, BLOKS, ICRS, MOCART) aid in evaluating degeneration and post-surgical repair maturation.

Conclusions:

• Optimal MRI protocols are critical for comprehensive joint cartilage assessment.
• Advanced imaging techniques and quantitative methods enhance the evaluation of cartilage health and repair.
• Future developments in isotropic 3D sequences promise improved diagnostic capabilities for articular structures.