Purpose: To determine the prevalence of active inflammatory changes around the pubic symphysis on MRI scans in patients with axial spondyloarthritis, and to evaluate its association with clinical factors.
Method: A retrospective analysis of MRI scans of 128 patients clinically diagnosed with axial spondyloarthritis was performed to assess the presence of active inflammatory changes around the pubic symphysis (bone marrow edema/osteitis and enthesitis). The clinical factors of the patients with and without active inflammatory changes around the pubic symphysis were compared.
Results: MRI scans showed active inflammatory changes around the pubic symphysis in 23 patients (18.0 %); 9 patients showed bone marrow edema/osteitis in the parasymphyseal pubic bone without soft tissue changes, 9 patients showed enthesitis with bone marrow edema/osteitis, and 5 patients showed enthesitis without bone marrow edema/osteitis. The median age of patients with active symphysis pubis changes was higher than that of those without active symphysis pubis changes (p < 0.001). C-reactive protein level and erythrocyte sedimentation rate in the active symphysis pubis group were both higher than those of the non-active symphysis pubis group (p = 0.001 and <0.001, respectively).
Conclusions: Active inflammatory changes around the pubic symphysis were seen in 18.0 % of the patients diagnosed with axial spondyloarthritis undergoing pelvic MRI, and were associated with older age and elevated acute phase proteins.
Keywords: Ankylosing spondylitis; Axial spondyloarthritis; Magnetic resonance imaging; Symphysis pubis.
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