MR imaging-based semiquantitative assessment in osteoarthritis.

Whole-organ semiquantitative (SQ) assessment by expert readers has become a powerful research tool in understanding the natural history of osteoarthritis (OA). SQ morphologic scoring has been applied to observational large cross-sectional and longitudinal epidemiologic studies in addition to interventional clinical trials. In comparison to quantitative and biochemical assessment of cartilage, SQ whole-organ scoring also analyzes additional joint structures that are potentially relevant as surrogate outcome measures for interventional approaches. Resources needed for SQ scoring rely on the MR imaging protocol, image quality, experience of the expert readers, method of documentation, and individual scoring system that is applied. This article discusses the different available OA whole-organ scoring systems, focusing on MR imaging of the knee, and also reviews alternative approaches.