Whereas the strength of scoring systems in osteoarthritis (OA) lies in detecting local changes, involving small parts of the structures of interest (ie, cartilage lesions), quantitative measures are powerful where minute changes occur homogeneously throughout large structures. Cartilage measurements at 1.5 or 3 Tesla are technically accurate, reproducible, and sensitive to change. The rate of change in knee OA was found to be 1% to 2% annually. Risk factors of cartilage loss include a high BMI, meniscal pathology, malalignment, advanced radiographic OA, bone marrow alterations, and focal cartilage lesions. MRI of articular tissues represents a potent tool in experimental, epidemiological and pharmacological intervention studies; however, it is only with the availability of disease modifying drugs that it will play a relevant role in clinical practice.