Baraliakos X, Richter A, Feldmann D, et al. - Experts performed a population-based cohort to examine the frequency of bone marrow oedema (BME) and fatty lesions (FL) suggestive of axial spondyloarthritis (axSpA) on MRI of the spine and sacroiliac joints (SIJ) in a general population sample. They examined MRIs of 793 individuals (49.4% males, mean age 37.3 ± 6.3 years, 8.4% human leucocyte antigen-B27+) aged <45 years. They found SIJ BME, VC BME and FL in 136, 218 and 645 volunteers, respectively. The data showed that SIJ BME in ≥ 1, ≥ 3 and ≥ 5 SIJ quadrants was found in 136 (17.2%), 7 (0.9%) and 1 (0.1%) volunteers, respectively. In this large population-based study, a high frequency of inflammatory and fatty MRI lesions indicative of axSpA was detected, particularly in the spine. The data demonstrates a limited value of such MRI findings for diagnosis and classification of axSpA. In addition, the rising frequency with age implies that mechanical factors could play a role.