Magnetic resonance imaging assessment of ASAS-defined active sacroiliitis in patients with inflammatory back pain and suspected axial spondyloarthritis: a study of reliability

The main purpose was to investigate the intra- and inter-rater reliability of the Assessment of SpondyloArthritis international Society (ASAS) definition of positive MRI for active sacroiliitis (ASAS-positive MRI), in a sample of patients with inflammatory back pain (IBP) and suspected axial spondyloarthritis (axSpA), who underwent sacroiliac joints (SIJ) MRI. We also evaluated the intra- and inter-rater reliability for the detection of the recently ASAS-refined findings indicating inflammatory activity.