SAT0633 Not a replacement but a possible substitution: detection of sacroiliitis on magnetic resonance enterography in patients with axial spondyloarthritis

Background MR Enterography (MRE), a part of the diagnosis in patients with inflammatory bowel disease (IBD), is increasingly used to exclude Crohn9s Disease (CD) in SpA patients with diarrhea. Two important retrospective studies1,2, on IBD suggest that acute and structural findings of sacroiliitis can be evaluated on MRE. But, it needs to be verified whether it really correlates with sacroiliac MRI. Objectives We aimed to determine whether assessment of sacroiliitis on MRE correlates with magnetic resonance imaging (MRI) of sacroiliac (SI) joint. Methods MREs used for screening of IBD in Axial SpA patients with chronic diarrhea and routine semi-coronal SI joint MR images were screened for the presence of acute inflammatory lesions and structural changes of the SI joint by the same radiologist in a blinded fashion to time and diagnosis. Firstly, MRE images and then MR images were evaluated on two separate occasions. Only patients with two imaging modalities with a maximum time distance of a month were evaluated. Results Forty-four patients with MRE imaging were included. Two MRE studies were excluded because of low resolution. Of those 11 patients (26%) had active inflammatory lesions involving mostly both SI joints and 3 had accompanying chronic structural changes. Ten patients (%24) in the MRE group had chronic structural changes, only. In the remaining 20 (47%) MRE evaluated patients SI joint were not affected. Twenty-five axSpA patients had both MRE and SI joint MRIs performed within a month. In 19 cases, out of 25 with both modalities the finding “no sacroiliitis” overlapped. An additional four patients had acute inflammatory lesions on both investigations. In only two patients either MRE or SI joint MRI had acute inflammatory lesions. In general, chronic structural changes overlapped in both modalities as well; Fourteen out of 25 patients with no changes and eight with chronic changes overlapped in both examinations. Both modalities differ in only three patients; Chronic changes was present in two patients in SI joint MRI and one patient in MRE only. Conclusions In SpA patients with chronic diarrhea a present MRE may substitute a conventional semi-coronal MRI of the SI joints and may hence decrease diagnostic expenses. Evaluation of MRE for the acute inflammatory and chronic structural changes of the SI joints may also have a place in the diagnostic flow in IBD patients referred by the gastroenterology clinics, as well. References Leclerc-Jacob, S., et al. The prevalence of inflammatory sacroiliitis assessed on magnetic resonance imaging of inflammatory bowel disease: a retrospective study performed on 186 patients. Alimentary pharmacology & therapeutics, 2014, 39.9: 957–962. Gotler, Jakob, et al. Utilizing MR Enterography for detection of sacroiliitis in patients with inflammatory bowel disease. Journal of Magnetic Resonance Imaging, 2015, 42.1: 121–127. Disclosure of Interest None declared