Prevalence and topographic distribution of spinal inflammation on MR imaging in patients recently diagnosed with axial spondyloarthritis.

OBJECTIVE: The primary goal of this study was to determine the prevalence and topographic distribution of spinal lesions in lower thoracic and lumbar spine on magnetic resonance imaging (MRI) in patients with recently diagnosed with spondyloarthritis. The secondary goal was to identify variables associated with vertebral patterns consistent with spondyloarthritis on MRI.

PATIENTS AND METHODS: A total of 112 HLA-B27 positive patients with recently diagnosed spondyloarthritis were retrospectively included. There were 70 women and 42 men, with a mean age of 41 years±12 (SD) (range: 17-70years). Mean symptom duration was 1year (range: 0-7years). MRI examinations of sacroiliac joints and thoracolumbar spine were reviewed for the presence of bone marrow edema, chronic structural abnormalities, and vertebral patterns consistent with spondyloarthritis. Age, gender and disease duration of patients with vertebral patterns on MRI consistent with spondyloarthritis were compared with those without MRI signs of spondyloarthritis.

RESULTS: Thirty-six patients (32.1%) showed spinal patterns of spondyloarthritis, including 16 patients (14.3%) with no associated inflammatory sacroiliitis. Posterior inflammatory lesions were present in 20.5% of patients. Posterior spinal inflammatory lesions were significantly associated with vertebral corner inflammatory lesions (P=0.03). There were no differences in age, sex or mean duration of symptoms between the two groups of patients.

CONCLUSION: Spinal involvement is observed in 32.1% of HLA-B27 positive patients with recently diagnosed spondyloarthritis and is not associated with sacroiliitis in 14.3%. Age, gender or symptom duration are not associated with spinal involvement on MRI.