Utility of repeat MRI in assessing treatment non-response in axial spondyloarthritis: data from two large tertiary...

The role of MRI of the spine/sacroiliac joints to aid the diagnosis of axial spondyloarthritis (axSpA) is well established. Limited data, however, exist on the use of MRI to assess disease activity, resulting in current Assessment of SpondyloArthritis International Society (ASAS)/European Alliance of Associations for Rheumatology (EULAR) guidelines not recommending the use of MRI for this purpose. We aimed to assess the current use of MRI to assess disease activity and its impact on clinical decision making.

As part of a service evaluation, we identified patients with a prior diagnosis of axSpA, who had an MRI of the spine/sacroiliac joints requested between May 2020 and December 2023 at The Leeds Teaching Hospitals Trust (Leeds) and Northwick Park Hospital (London). Clinical and demographic data were extracted from the medical notes. Data on MRI findings were extracted from the radiologist's report.

Overall, 346 scans were performed in 335 patients. 301 patients had axSpA (170 radiographic axSpA, 131 non-radiographic axSpA) and 31 axial psoriatic arthritis. Patients were predominantly male (60.0%) and HLA-B27 positive (60.6%). 140/172 (80.1%) of patients had evidence of inflammation on a pre-treatment MRI scan. 224 scans (64.7%) were performed in patients on biologic/targeted synthetic disease-modifying antirheumatic drugs. Of the 346 MRIs performed during the audit period, 179 (54.7%) had evidence of active inflammation and those with active inflammation were more likely to have their treatment escalated (59.3% vs 23.2%).

MRI is of utility in assessing disease activity with results of MRI scans directly influencing treatment decision making at the bedside. Further research exploring the relationship between MRI findings and clinical outcomes is warranted.