Update on imaging in rheumatic diseases: cartilage

Area of Science:

• Biomedical Imaging
• Orthopedics
• Rheumatology

Background:

• Articular cartilage plays a crucial role in understanding joint disease pathogenesis and clinical research.
• Historically, cartilage assessment was invasive; now, various non-invasive imaging modalities are available.
• Conventional radiography has limitations, assessing cartilage indirectly via joint space width.

Purpose of the Study:

• To review current and emerging imaging techniques for articular cartilage evaluation.
• To highlight the capabilities of ultrasound (US) and magnetic resonance imaging (MRI) in assessing cartilage quality and composition.
• To discuss the potential of novel, contrast agent-free MRI techniques for early detection of cartilage changes.

Main Methods:

• Ultrasound (US) for evaluating cartilage thickness and structure.
• Magnetic resonance imaging (MRI) for high-resolution morphological assessment.
• Advanced MRI sequences (dGEMRIC, T2/T2*-mapping, T1ρ-mapping, gagCEST, sodium imaging) for quantitative analysis of cartilage composition and early changes.

Main Results:

• US reliably assesses cartilage thickness and structure.
• MRI provides high-resolution morphological imaging and quantitative compositional analysis, even in small joints.
• Novel contrast agent-free MRI techniques show promise in detecting early cartilage changes before morphological alterations are visible.

Conclusions:

• US and MRI are essential tools for the non-invasive assessment of articular cartilage.
• Advanced MRI techniques offer quantitative biomarkers for early detection of cartilage disease.
• These imaging modalities will be crucial for future clinical trials and daily practice in managing inflammatory and degenerative joint diseases.