The utility of repeating MRI of the sacroiliac joints (MRI-SI) after 3 months or 1 year in the diagnostic process of patients with early chronic back pain who are suspected of having axial spondyloarthritis (axSpA) is very limited, according to the results of the multinational Spondyloarthritis Caught Early cohort study published in Arthritis & Rheumatology.
The investigators sought to examine the importance of repeating MRI-SI in patients with chronic back pain with suspected axSpA and to assess determinants of MRI-SI positivity. Patients from the study cohort with chronic back pain for ≥3 months and ≤2 years, with disease onset at <45 years and ≥1 SpA characteristic, underwent baseline, 3-month, and 1-year visits. At each visit, SpA features were evaluated and MRI-SI was repeated. MRI-SI positivity, based on the Assessment of Spondyloarthritis international Society (ASAS), was evaluated by 2 or 3 well-trained readers who were blinded to clinical information.
A total of 188 patients were assessed, 38.3% of whom where men. The mean participant age was 31.0 ± 8.2 years, mean symptom duration was 13.2 ± 7.1 months, and 16.5% of patients were MRI-SI positive at baseline. After the 3-month and 1-year follow-up visits, 11.1% (3 of 27) of patients and 16.5% (11 of 29) of patients, respectively, changed from MRI-SI positive to negative. The researchers note that this was, in part, the result of the initiation of tumor necrosis factor inhibitor therapy. Furthermore, changes from MRI-SI negative to positive were observed in 4.3% (5 of 116) of participants and 7.2% (10 of 138) of patients, respectively.
Human leukocyte antigen B27 (HBA-B27) positivity and male gender were independently associated with the likelihood of a positive MRI-SI at any time point (42% in HLA-B27-positive men and 6% in HLA-B27-negative women). If the baseline MRI-SI was negative, the likelihood of a positive MRI-SI during follow-up was shown to be quite low, at a maximum of 7%.
The investigators concluded that changes in MRI-SI ASAS status are reported among only a minority of patients. Therefore, repeating an MRI-SI after 3 months or 1 year in the diagnostic workup of patients with early chronic back pain, in an effort to predict their risk of developing axSpA, is not particularly beneficial.
Bakker PA, Ramiro S, Ez-Zaitouni Z, et al. Is it useful to repeat MRI of the sacroiliac joints after three months or one year in the diagnostic process of patients with chronic back pain suspected of axial spondyloarthritis? [published online September 11, 2018]. Arthritis Rheumatol. doi:10.1002/art.40718