Abstract

Aim: Until recently, the treatment of ankylosing Spondylitis(AS) was restricted to non steroid anti-inflammatory drugs (NSAID) and physical therapy. Since the anti-tumor necrosis factor ? (TNF ?) blocking agents (infliximab, etanercept or adalimumab) are effective treatments and improve most of the clinical parameters and functional capacity. Today, early diagnosis and treatment of AS is more important. As conventional radiography only shows late changes, magnetic resonance imaging (MRI) suggested showing both early clue of inflammation on soft tissue, cartilage and response to treatment. As MRI is expensive, not readily available and time consuming method, we aimed to find out some physical finding and laboratory data to increase sensitivity and accuracy of the MRI for clinicians in AS diagnosis. Methods: Forty six patients with inflammatory back pain (18 males) with normal conventional radiographs of sacroiliac joints were included in the study. Rheumatologic evaluation with ability of chest expansion, sacroiliac MRI and routine laboratory tests, including HLA B27(Human Leukocyte Antigen Subgrup B 27), CRP and ESR (Erytrocyt Sedimantation Rate) were measured. Results: Out of 46 patients with inflammatory back pain and normal conventional radiography of sacroiliac joint and thoracic-lumbar vertebra, 8 had sacroiliitis on MRI with average 7 years of disease duration. Decreased chest expansion, HLA B27 positivity, high CRP value, longer disease duration were significantly common in patients with positive MRI finding for axial spondylitis (p<0,05). On logistic regration analysis, high CRP values and longer disease duration correlated more strongly with positive MRI findings (r =0,8). Conclusion: Patients with inflammatory back pain with normal conventional radiographs, longer disease duration with high CRP, (+) HLAB27 and decreased chest expansion may increase probability of finding axial spondylitis with MRI.