Frequency of MRI changes suggestive of axial spondyloarthritis in the axial skeleton in a large population-based cohort of individuals aged 45 years (original) (raw)

Annals of the Rheumatic Diseases

What is already known about this subject? ► The sensitivity and specificity of the Assessment of SpondyloArthritis international Society criteria for a 'positive' MRI for the classification of axial spondyloarthritis (axSpA) have been challenged due to high sensitivity with relatively low specificity. What does this study add? ► There seems to be a relatively high frequency of inflammatory and fatty spinal/inflammatory sacroiliac joints (SIJ) and spinal MRI lesions suggestive of axSpA in the general population. ► Such MRI changes tend to occur more frequently in patients of higher age groups, suggesting an influence of a mechanical factor and potential development of osteoarthritis. How might this impact on clinical practice or future developments? ► Caution is needed to take 'a positive MRI' as proof that a patient has axSpA, especially in the absence of clear clinical symptoms indicative of the disease. ► These data suggest that the current definition of MRI changes in the SIJ used for the classification of axSpA need an update. AbSTrACT Objective To investigate 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. Methods as part of a community-based cohort project (study of Health in pomerania), volunteers underwent spinal (sagittal T1/T2) and siJ (semicoronal short tau inversion recovery) mRi examinations. Two calibrated readers evaluated the images to detect BmE in siJ and vertebral corners (Vc) and Fl in Vc suggestive of axspa using assessment of spondyloarthritis international society definitions. results mRis of 793 volunteers (49.4% males, mean age 37.3±6.3 years, 8.4% human leucocyte antigen-B27+) aged <45 years were evaluated. siJ BmE was seen in 136 (17.2%), Vc BmE in 218 (27.5%) and Fl in 645 (81.4%) volunteers. siJ BmE in ≥1, ≥3 and ≥5 siJ quadrants was seen in 136 (17.2%), 7 (0.9%) and 1 (0.1%) volunteers, respectively. in Vc, BmE≥1, ≥3 and ≥5 lesions were seen in 218 (27.5%), 38 (4.8%) and 6 (0.8%) volunteers, respectively, while Fl≥1, ≥3 and ≥5 were seen in 645 (81.3%), 351 (44.3%) and 185 (23.3%) volunteers, respectively. logistic regression analysis showed that BmE and Fl in Vc were related to increasing age: oR 1.33, 95% ci 1.02 to 1.72, and oR 1.73, 95% ci 1.32 to 2.27, per decade increase, respectively. Conclusions in this large population-based study, a high frequency of inflammatory and fatty mRi lesions suggestive of axspa was found, especially in the spine. This indicates a limited value of such mRi findings for diagnosis and classification of axspa. The increasing frequency with age suggests that mechanical factors could play a role.