Imaging of knee osteoarthritis.

New imaging modalities are broadening the possibilities in osteoarthritis (OA) research, and are offering new insights to help better understand the pathogenesis of this disease. Although knee radiographs are widely employed in epidemiological and clinical studies to assess structural pathology, joint radiographs provide limited outcome measures in knee OA, and other more valid, reliable and sensitive imaging modalities are now available. In particular, magnetic resonance imaging can directly visualize articular cartilage and other joint structures, such as bone and soft tissue, that are now recognized as part of the disease process. This chapter will examine imaging modalities in the assessment of knee OA, and the impact of these on our understanding of the pathogenesis of this disease.