Imaging of knee osteoarthritis: data beyond the beauty

MRI has revolutionized osteoarthritis research by providing semi-quantitative and quantitative imaging endpoints on most articular tissues. With the first image data of the Osteoarthritis Initiative now becoming publicly available, this article reviews recent developments in quantitative imaging of osteoarthritis.

Although radiography remains the standard for regulatory studies on disease modifying osteoarthritis drugs, there is no consensus on the optimal positioning and acquisition protocol. With MRI, semi-quantitative scoring systems for evaluation of multiple articular tissue changes have been developed and are currently investigated in the context of correlation with symptoms and of predicting structural progression of osteoarthritis. Most efforts on quantitative measurement of imaging endpoints have focused on cartilage morphology and composition, with higher field strength (3T), newer sequences, and new measurement endpoints being a driver of current innovation.

The semi-quantitative and quantitative tools for analysis of articular structure are now available and permit comprehensive analysis of morphological and compositional tissue changes in osteoarthritis. These changes will need to be related to clinical outcomes (e.g. how a patient feels or functions) with current epidemiological studies, such as the Osteoarthritis Initiatives, providing the opportunity for clinical validation of these imaging biomarkers.