How important is MRI for detecting early osteoarthritis?

Osteoarthritis (OA) is a major public health problem. Plain radiography, which mainly depicts joint-space narrowing and osteophytes, is useful for defining OA, but has weak associations with symptoms, limited sensitivity to change, as well as poor prediction of cartilage loss and the need for joint replacement. In addition, considerable changes occur before the development of the first radiographic abnormalities; for example, >10% of knee cartilage volume is lost and a >40% prevalence of knee cartilage defects is observed2 by the time the earliest radiographic changes are present. MRI, with standard techniques such as fat-saturated, T1-weighted, spoiled gradient echo sequences and T2-weighted, proton-density-weighted fast-spin echo sequences, has been utilized to directly assess knee structural alterations, such as cartilage volume, cartilage defects, subchondral bone changes and meniscal lesions, which has increased our understanding of early joint changes