Summary

There are two different types of cartilage imaging modalities, which address either its morphology or composition. Cartilage morphology is first indirectly assessed in clinical practice using radiographs, which are still the first line examination due to its low cost, availability, and reproducibility, as well as feasibility in the standing position and increased sensitivity with specific patient positioning (fixed flexed knee radiograph and Lequesne view
for the hip). MRI is the only imaging examination, which can show all the joint components, including the cartilage, the subchondral bone, and bone marrow lesions, which are highly correlated with pain. However,MRIis not indicated in osteoarthritis unless the patient complaints of dull pain unexplained at radiography. CT-Arthrography and MR-arthrography, which provide a direct and detailed image of the cartilage, but require the intra-articular injection of a contrast media, are indicated only when a very detailed image of the cartilage is required.MRImayalso address the cartilage composition with special acquisition sequences providing a quantitative evaluation of the proteoglycans or collagen alterations, which occur before the morphologic changes and which constitutes an advanced research tool to further understand osteoarthritis pathogenesis and evaluate future treatments.