POS1005 ACTIVE INFLAMMATORY LESIONS OF THE SPINE IN SACROILIAC JOINTS MRI (SIJs-MRI): AN OVERLOOKED FINDING BY RADIOLOGISTS.

Abstract

BackgroundEstablishing a diagnosis for axial spondylarthritis (axSpA) is based on the combined presence of several clinical and laboratory features in association with imaging: the presence of active inflammatory lesions (bone marrow edema, BME) in sacroiliac joints (SIJs), also associated with structural lesions, is the main element in favor of a diagnosis of axSpA and SIJ MRI is currently the main recommended technique for detecting inflammation, enabling early diagnosis in patients with normal radiographic findings. MRI of the spine is generally not recommended for axSpA diagnosis, since spine involvement is considered less sensitive and specific. Several studies explored the incremental value of spine MRI for diagnosing patients with axSpA, especially when the findings of SI are equivocal, and “predicting” clinical disease activity.ObjectivesTo evaluate the effectiveness of the MRI study dedicated to SIJs to identify the inflammatory involvement of the lumbar spine in patients with active sacroiliitis and clinical diagnosis of axSpA.MethodsMRI of 96 patients (26 M, 70 F, mean age 48 years) with SIJs-MRI positive for inflammatory involvement according to ASAS criteria, were evaluated retrospectively. The presence of signs of inflammation of posterior spinal elements and vertebral bodies included in the field of vision (FOV) was therefore researchedResultsOf 96 patients with active sacroiliitis, 88 had concomitant inflammatory lesions of the lumbar spine. Facet capsulitis (87.6 %) and posterior enthesitis (42.2 %) were the most common lesions and these lesions frequently coexisted (39.3%). Twelve patients with facet capsulitis presented also facet arthritis. Only 20 out of 96 patients (22%) had vertebral bodies inflammatory lesions: 15 corner inflammatory lesions and 5 aseptical spondylodiscitis.ConclusionOn the basis of current working consensus MRI examination of the spine is not recommended for axSpA diagnosis, because it is considered less sensitive and specific. However the high prevalence (91.7%) of spinal inflammatory changes in patients with active sacroiliitis suggests that these features can be used as an additional element in favor of diagnosis, especially in doubtful cases. This evaluation takes little reporting time, without any increase in MRI execution time.