Imaging: spine

Although axial spondyloarthritis (axSpA) starts in the sacroiliac joints in the vast majority of cases, the spine can be clinically affected with similar severity and frequency, especially in long-standing disease. In addition, not only the inflammatory but also structural changes seen in the sacroiliac joints can be visualized in the same way in the spine when using the appropriate imaging techniques. For the interpretation of imaging findings in axSpA, typical and frequent differential diagnoses need to be taken into account, such as degenerative changes, bacterial inflammation, and fractures, and also non-pathological findings such as haemangioma. This chapter concentrates on the imaging of the spine in axSpA, giving an extensive overview of the relevant diagnostic and differential diagnostic findings in patients with axSpA and the most common differential diagnoses.