de Winter J, et al. - Researchers compared the magnetic resonance images (MRIs) of the sacroiliac (SI) joints of healthy subjects and individuals with known mechanical strain acting upon the SI joints to those of patients with axial spondyloarthritis (SpA) and patients with chronic back pain. A positive MRI for sacroiliitis according to the Assessment of SpondyloArthritis international Society (ASAS) definition was seen in a substantial proportion of healthy individuals without current or past back pain. Findings suggest almost an exclusive presence of deep (extensive) bone marrow edema (BME) lesions in axial SpA patients.