Degeneration of the articular cartilage is often observed in patients with knee osteoarthritis. In recent years, several qualitative MR imaging techniques that evaluate deterioration of biochemical components in articular cartilage have been developed. Delayed gadolinium-enhanced MR imaging of cartilage (dGEMRIC) is an MR imaging technique that can evaluate the glycosaminoglycan (GAG) concentrations in articular cartilage. While T2 (transverse relaxation time) mapping is an MR imaging technique that can evaluate the hydration and collagen fiber integrity in articular cartilage. dGEMRIC and T2 mapping can provide useful noninvasive evaluations of cartilage matrix status, and they can be useful for the detection of knee osteoarthritis at earlier stages.