The prevalence of inflammatory sacroiliitis assessed on magnetic resonance imaging of inflammatory bowel disease: a retrospective study performed on 186 patients

Background Magnetic resonance imaging (MRI) colonography or enterography is increasingly used to assess disease activity and complications in inflammatory bowel disease (IBD). However, no study has evaluated the role of this imaging technique to assess sacroiliitis. Aim The primary objective was to assess the prevalence of inflammatory sacroiliitis on MRI performed for IBD investigation. The secondary aim was to elucidate clinico-biological factors associated with the presence of sacroiliitis. Methods This study was performed on 186 patients suffering from IBD followed in a gastroenterology department between 2004 and 2011: 131 with Crohn's disease and 55 with ulcerative colitis. Clinico-biological and endoscopic data were collected and MR enterography or colonography was performed to assess IBD activity on axial and coronal fat suppressed injected T1-weighted sequences. On MRI, sacroiliitis was scored blindly by two independent readers according to ASAS (Assessment of SpondyloArthritis international Society) criteria. Results The prevalence of inflammatory sacroiliitis was 16.7% (n=31). Sacroiliitis was bilateral in 14 cases and unilateral in 17 cases. The sacroiliac joints were considered normal in 144 cases and doubtful in 11 cases. Older age and female gender were significantly associated with the presence of sacroiliitis. Other factors such as type of IBD, disease duration and localisation of IBD, surgery history, biological inflammation, bowel disease activity and treatment were not associated with sacroiliitis. Conclusion Inflammatory sacroiliitis was evidenced by MRI in 16.7% in patients suffering from IBD. Added to clinico-biological data, MRI analysis should contribute to an earlier diagnosis of axial spondylarthritis in patients with IBD.