Type:
Educational Exhibit
Keywords:
Imaging sequences, Education, MR, Musculoskeletal bone, Musculoskeletal joint, Bones, Arthritides, Inflammation
Authors:
A. Piasentier, L. Cereser, M. Lorenzon, A. zabotti, L. Quartuccio, S. De Vita, R. Girometti, C. Zuiani; Udine/IT
DOI:
10.26044/ecr2019/C-2534
Background
Spondyloarthritis (SpA) describes a group of interrelated disabling chronic inflammatory diseases,
including ankylosing spondylitis, psoriatic arthritis,
arthritis associated with inflammatory bowel disease (IBD) and reactive arthritis. The clinical presentation may be very heterogeneous,
but patients with SpA can be distinguished according to their presentation as axial (axSpA) or peripheral SpA [1]. AxSpA predominantly affects the spine and the sacroiliac joints (SIJs). The main diagnostic imaging feature to diagnose axSpA is sacroiliitis. The old modified New York criteria for ankylosing spondylitis took into account the presence of radiographic changes in the SIJs to assess sacroiliitis,
which can take years to manifest [2].
The use of MRI and its incorporation into the Assessment of Spondyloarthritis (ASAS) criteria (Table 1) [3] has radically changed the diagnosis of SpA by allowing visualization of both active and chronic inflammatory changes.
AxSpA may be distinguished according to the presence of structural damage on pelvic X-Ray in:
- Radiographic axial spondyloarthritis (also termed ankylosing spondylitis): patients who have already developed structural damage visible on radiographs.
- Non-radiographic axial spondyloarthritis: patients without such structural damage but who show active sacroiliitis on MRI.
The main feature of active sacroiliitis is represented by bone marrow oedema (BMO) in the SIJs. Non-radiographic axSpA may be seen as an earlier or milder part of axSpA,
and patients might or might not develop structural bony damage in the axial skeleton.
The European League Against Rheumatism (EULAR) recommends MRI in cases of clinical suspicion of axSpA and pelvic X-rays showing normal or equivocal findings. In clinical practice,
SIJ MRI can be useful diagnostically in those patients with a clinical suspicion of inflammatory back pain who are HLA-B27-positive,
have a normal or equivocal radiograph of the SI joints,
have an insufficient symptomatic response to Non-steroidal anti-inflammatory drugs (NSAIDs),
and are considered candidates for more intensive therapy.
Thanks to SIJ MRI clinicians are able to recognize SpA during its early stage, ensuring appropriate and effective therapeutic management [4].
Although the presence of subchondral BMO in the SIJs should be regarded as essential to meet the definition of active sacroiliitis,
it may be detected in other diseases or as an incidental finding.