Imaging in axial spondyloarthritis: diagnostic problems and pitfalls.

Magnetic Structural changes in axial Spondyloarthritis (axSpA) are best identified by conventional radiographs, while magnetic resonance imaging (MRI) is considered the gold standard for assessment of inflammatory changes. Imaging of the axial skeleton is crucial for the diagnosis but also for classification to non-radiographic axSpA according to the 2009 ASAS classification criteria. Despite the existing definitions for a positive MRI for the sacroiliac joints and the spine, these predefined lesions can also be seen in other conditions, representing pitfalls and false-positive conclusions in patients with similar clinical symptoms who do not have SpA. Diagnosis of SpA should result from the combination of clinical, laboratory and imaging findings.