[Magnetic resonance imaging (MRI) diagnostics in axial spondyloarthritis]

Axial spondyloarthritis (axSpA) is a frequent disorder, which is difficult to diagnose in the early phase. Currently, magnetic resonance imaging (MRI) of the sacroiliac joints and the spine is frequently applied in this phase, when conventional X rays still provide inconclusive results.

To explain the typical pathological results and the role of MRI in diagnosing axSpA.

The use of MRI of the sacroiliac joints plays a central role in the assessment of the Spondyloarthritis International Association Society (ASAS) classification criteria of axSpA. Bone marrow edema is central to the definition of a positive MRI of the sacroiliac joints. In addition, chronic changes in the sacroiliac joints, such as fat depositions and erosion are taken into account in making the diagnosis of axSpA. When the results are not clear, an additional MRI of the area of the spine in which the patient reports the most pronounced complaints can be performed. A bone marrow edema in at least three vertebral edges can be associated with axSpA.

The MRI investigation of the sacroiliac joints has evolved into one of the most important methods in diagnosing axSpA.