Insights of cartilage imaging in cartilage regeneration

Table 1 Comprehensive comparison of cartilage imaging modalities

Imaging modality	Technical requirements	Key strengths	Primary limitations	Clinical utility
Radiography	Basic X-ray systems; optional diffraction-enhanced setups	Widely available; economical; excellent for assessing bony landmarks and joint space	Indirect cartilage evaluation; radiation exposure; limited soft-tissue contrast	Baseline assessment of joint integrity; detection of osteophytes and subchondral changes
Ultrasound	High-frequency transducers (≥ 20 MHz); skilled operator	Real-time imaging; portable; cost-efficient for superficial structures	Operator dependency; anisotropy artifacts; limited penetration for deep joints	Rapid evaluation of superficial cartilage defects, particularly in small joints
CT arthrography	CT scanner; intra-articular contrast; experienced personnel	High spatial resolution; excellent for visualizing osteochondral interfaces	Invasive contrast injection; radiation dose; suboptimal soft-tissue contrast	Detailed assessment of cartilage in small joints; evaluation of osteochondral lesions
MRI (morphological)	1.5 T/3 T MRI systems; dedicated coils; standard sequences	Superior soft-tissue contrast; multi-planar capabilities; non-ionizing	Longer scan times; less sensitive to early biochemical alterations	Detailed structural evaluation; mapping of lesion extent and subchondral involvement
MRI (compositional)	Advanced MRI protocols; specialized sequences (e.g., T2 mapping, dGEMRIC)	Quantitative assessment of biochemical changes; early detection of degenerative markers	Higher cost; technical complexity; standardization challenges	Early diagnosis of cartilage degeneration; monitoring of regenerative therapies

CT: Computed tomography; MRI: Magnetic resonance imaging; dGEMRIC: Delayed gadolinium-enhanced magnetic resonance imaging of cartilage.