Active inflammatory changes around the pubic symphysis in patients with axial spondyloarthritis: Magnetic resonance imaging characteristics and association with clinical factors.

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.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.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).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.