Aydin SZ, Maksymowych WP, Bennett AN et al.
Medeniyet University, Istanbul, Turkey.
Ann Rheum Dis 2012;71:56–60.
Editor’s note: One of the major factors that can affect outcomes in axial spondyloarthritis is delay in diagnosis, which averages 7–9years. This can be caused by the slow rate of radiographic progression in the sacroiliac joints. The Assessment of Spondyloarthritis International Society (ASAS) criteria classify axial spondyloarthritis into human leukocyte antigen (HLA)-B27 and imaging-based arms, arguing that magnetic resonance imaging (MRI) can substantially reclassify patients into different diagnostic categories (Ann Rheum Dis 2009;68:777–83). New criteria by a working group from ASAS and Outcome Measures in Rheumatology network class a positive MRI for sacroiliitis in axial spondyloarthritis patients as the presence of bone marrow edema on short τ inversion recovery sequence or osteitis on gadolinium-enhanced T1-weighted fat suppressed images (Ann Rheum Dis 2009;68:1520–7). This study was carried out in order to assess the diagnostic and prognostic validity of the imaging and HLA-B27 arms of the ASAS classification criteria in a cohort of patients with inflammatory back pain (IBP), and to explore the utility of the ASAS definition of a positive MRI for sacroiliitis.