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SummaryBackgroundThe objective of this study was a comparative evaluation of radiography and MRI in the diagnostics of sacroiliitis in patients with a clinical diagnosis of spondyloartropathy, according to the current ASAS criteria.Material/MethodsSacroiliac joints radiograms and MRI were conducted in 101 consecutive patients, aged 19–71 yrs (mean age: 40.6 yrs). The patients were referred by a senior rheumatologist, with symptoms of the chronic back pain. The sacroiliac joints were assessed on AP radiograms of the pelvis according to the modified New York criteria for ankylosing spondylitis. MRI was performed to look for active and chronic inflammatory lesions.ResultsOf 14 patients with radiographic sacroiliitis according to modified New York criteria, only 50% had sacroiliitis on MRI. The sensitivity and specificity of conventional radiography were 22% and 94% and of MRI were 71% and 90%. Cohen’s kappa coefficient was κ=0.0187, agreement of radiograms and MRI was 58%. Among 86 patients displaying no sacroiliitis on radiograms, MRI showed sacroiliitis in 34 patients (39.5%). Positive predictive value was 0.429, negative predictive value was 0.605.ConclusionsMRI allowed to diagnose sacroiliitis in 39,5 % of patients in preradiographic stage. MRI ruled out the presence of active inflammatory lesions in 60.4% of patients with sacroiliitis on radiograms according to modified New York criteria.

Juvenile idiopathic arthritis is the most common autoimmune systemic disease of the connective tissue affecting individuals in the developmental age. Radiography, which was described in the first part of this publication, is the standard modality in the assessment of this condition. Ultrasound and magnetic resonance imaging enable early detection of the disease which affects soft tissues, as well as bones. Ultrasound assessment involves: joint cavities, tendon sheaths and bursae for the presence of synovitis, intraand extraarticular fat tissue to visualize signs of inflammation, hyaline cartilage, cartilaginous epiphysis and subchondral bone to detect cysts and erosions, and ligaments, tendons and their entheses for signs of enthesopathies and tendinopathies. Magnetic resonance imaging is indicated in children with juvenile idiopathic arthritis for assessment of inflammation in peripheral joints, tendon sheaths and bursae, bone marrow involvement and identification of inflammatory lesions in whole-body MRI, particularly when the clinical picture is unclear. Also, MRI of the spine and spinal cord is used in order to diagnose synovial joint inflammation, bone marrow edema and spondylodiscitis as well as to assess their activity, location, and complications (spinal canal stenosis, subluxation, e.g. in the atlantoaxial region). This article discusses typical pathological changes seen on ultrasound and magnetic resonance imaging. The role of these two methods for disease monitoring, its identification in the pre-clinical stage and establishing its remission are also highlighted.