AB0007 VALUE OF ULTRASOUND IN ASSESSMENT OF ACTIVE SACROILIITIS IN PATIENTS WITH AXIAL SPONDYLOARTHRITIS
Authors: M. Chen, S. M. Dai
Journal: Annals of the Rheumatic Diseases (2020)

Background: The inflammatory of the sacroiliac joints (SIJs) called sacroiliitis, is a characteristic of axial Spondyloarthritis (axSpA). The detection of sacroiliitis is meaningful to prevent irreversible changes. The tool of assessment of sacroiliitis including radiographs, computed tomography (CT) and magnetic resonance imaging (MRI). Ultrasound (US) has also been used in the evaluation of sacroiliitis in recent years. Objectives: We aimed to evaluate the value of US in the assessment of active sacroiliitis in axSpA patients. Methods: Fifty-one patients fulfilling Assessment of SpondyloArthritis International Society (ASAS) 2009 criteria for the classification of axSpA were recruited 1 . All the patients underwent MRI and US evaluation of bilateral SIJs. MRI was performed using the sequences of T1WI, T2WI and fat suppression T2WI (FS-T2WI). MRI sacroiliitis was defined according to ASAS criteria of active sacroiliitis 2 . The Spondyloarthritis research Consortium of Canada (SPARCC) scoring was used to evaluate the inflammatory lesions in SIJs 3 . US were performed by an ultrasonographer with 10 years of experience in musculoskeletal ultrasound, and resistive index (RI) value was recorded. The US sacroiliitis was defined as the presence of more flow signals at SIJ with an RI ≤ 0.75. The HLA-B27, erythrocyte sedimentation rate (ESR) and hypersensitive C-reactive protein (hsCRP) were also evaluated. Consistency rate, sensitivity, specificity, positive predictive values (PPV) and negative predictive values (NPV)for the diagnosis of sacroiliitis by US were calculated, using MRI as the gold standard. Results: Of the 51 patients, 24 were female and 27 were male. The HLA-B27 positive rate was 90.2% (46/51). The consistency rate of US and MRI sacroiliitis was 55.88 (57/102). The sensitivity and specificity of US for the diagnosis of sacroiliitis were 55.93 (33/59) and 55.81 (24/43) respectively. The PPV and NPV were 63.46 (33/52) and 48 (24/50) respectively. There was no significant difference in ESR and hsCRP between the US positive sacroiliitis and the others (P= 0.7477 and 0.2268, respectively). The SPARCC scores have no significant difference between the US positive sacroiliitis and the others (P= 0.2206). The RI was not significantly associated with the MRI SPARCC score (P=0.4236). Conclusion: US may be an optional method for preliminary screening sacroiliitis. But its reliability as a diagnostic method needs further verification. References: [1]Rudwaleit M, et al. The development of Assessment of SpondyloArthritis international Society classification criteria for axial spondyloarthritis (part II): validation and final selection. Ann Rheum Dis. 2009; 68(6):777-83 [2]Rudwaleit M, et al. Defining active sacroiliitis on magnetic resonance imaging (MRI) for classification of axial spondyloarthritis: a consensual approach by the ASAS/OMERACT MRI group. Ann Rheum Dis 2009;68(10):1520–7 [3]Maksymowych WP, et al. Spondyloarthritis research Consortium of Canada magnetic resonance imaging index for assessment of sacroiliac joint inflammation in ankylosing spondylitis. Arthritis Rheum.2005;53(5):703-9. Acknowledgments: This project was supported by grants from National Natural Science Foundation of China (81900795) Disclosure of Interests: None declared