Age related contrast need for diagnosis of activesacroiliitis

Sero-negative spondylo-arthropathies are a heterogeneous group of diseases primarily involving sacroiliac joints and the vertebrae. The prototype is Ankylosing Spondylitis. The earliest and most characteristic findings of ankylosing spondylitis are observed in the sacroiliac joint. For the diagnosis of sacroiliitis, clinical findings, laboratory data and physical examination have limited role. For this reason, imaging methods are important. Radiographyis the first line imaging modality,howevermagnetic resonance imaging is accepted as the most efficient imaging modality to diagnose the early and active sacroiliitis. In this study, the aim was to investigate the need for contrast agent in the diagnosis of active sacroiliitis by detecting active and chronic sacroiliitis findings before and after contrast material in sacroiliac MR examinations of clinically diagnosed or suspected sacroiliitis patients. 118 patients (76 female, 42 male) who had undergone sacroiliac MR imaging between November 2016 and January 2017 with either diagnosis or clinical suspicion of Ankylosing Spondylitis, were evaluated retrospectively. The cases were divided into 3 groups according to age (18-25 years, 26-45 years and over 46 years old).Two radiologists assessed pre-contrast sequences in the first session and all sequences obtained before and after contrast in the second session on different days, unaware of each other and the patient's clinical and demographic information. Imaging findings were examined in terms of ASAS criteria, precontrast and postcontrast differences were investigated. According to the results of the first radiologist, the post-contrast series did not provide an additional contribution to define osteitis for active sacroiliitis in all three age groups. In the results of the second radiologist, post-contrast series were statistically significant in defining osteitis only in 46 years old and over group. In conclusion, the results of this study revealed that the contrast-enhanced series do not have a significant superiority compared to STIR sequence to diagnose active sacroiliitis, especially in young and middle-aged patient age groups. Key words:Spondyloarthropathy, Sacroiliitis, Sacroiliac MR, STIR