SAT0373 QUANTITATIVE ASSESSMENT OF RESPONSIVENESS IN SACROILIAC JOINTS MRI OF PATIENTS WITH AXIAL SPONDYLOARTHRITIS: A PILOT STUDY.
Authors: C. Garrido-González, M. D. C. Castro Villegas, M. Ladehesa Pineda, J. L. Garrido-Castro, R. Ortega Castro, C. Gonzalez-Navas, P. Zarco-Montejo, R. Almodovar, A. Bueno, L. M. Molinero, E. Collantes Estevez
Journal: Annals of the Rheumatic Diseases (2020)

Background: The presence of inflammatory signals in sacroiliac joints (SIJ), using MRI, is used for early diagnosis of axial spondyloarthritis (axSpA)[1]. Some studies also demonstrate that this inflammation can be suppressed quite dramatically by TNF-α blockers. Different scoring methods to quantify inflammatory changes in SIJ using MRI have been defined and validated: SPARCC, Leeds, Berlin, and ASSpiMRI-a. However, its use is complex and subjective. Recently Zarco et al[2] developed a method to measure bone marrow edema (BME) in MRI images from SIJ. This method, in a semiautomatic procedure, allows to measure the area affected by inflammation and the signal intensity to produce an index: the SCAISS. A simplified version, the s-SCAISS, using only a semi-coronal slide, has been proposed with good validity and reliability results. Objectives: To assess responsiveness of inflammation in SIJ of axSpA patients, treated with TNF-α inhibitors, using a novel score method: the s-SCAISS. Methods: Two rheumatologists independently quantified SIJ images from axSpA patients by three methods (s-SCAISS, SPARCC and Berlin) on a single semi-coronal MRI slide (STIR). Patients were assessed before TNF-α therapy (PRE) and 3 months later (POST). Spearman correlations was used to analyze relationship between variables, Wilcoxon signed-rank test for significant differences and Cohen’s d for calculating the effect size of improvement. Figure shows MRI images of a patient before and after treatment. Results: 9 axSpA patients were recruited from the COSPAR cohort (44% female, age 47±13 years, disease duration 18±14 years, BMI 29±4). Results PRE and POST are shown in Table: mean values (sd), statistical significance (NS, not significant; *, p&lt;0.05; **, p&lt;0.01), and Effect Size. In the first rows, different scoring system for MRI inflammation appears: Area analyzed by s-SCAISS, s-SCAISS, Berlin and SPARCC (using only a semi-coronal slide). Activity and functional indexes were lower with significant differences and a large effect size. Correlations of s-SCAISS with Berlin (rho=0.78;p&lt;0.05) and SPARCC (rho=0.96;p&lt;0.001) were good; with clinical disease activity outcomes were poor, except with BASDAS (rho=0.70;p&lt;0.05). The best correlation according improvements appeared comparing reduction of ASDAS with reduction of s-SCAISS (rho=0.57) but this difference was not significant. Although improvements in BASMI was not significant, a good correlation was found between improvement in s-SCAISS and BASMI (rho=-0.72;p&lt;0.05). PRE POST Sign E.S. Area 71.33 (66.71) 20.89 (39.02) ** 0.86-Large s-SCAISS 118.67 (114.6) 27.78 (51.09) ** 0.98-Large BERLIN 2.33 (1.66) 0.67 (1.12) ** 1.14-Large SPARCC 3.11 (2.26) 0.78 (1.39) ** 1.18-Large CRP 13.1 (9.4) 4.1 (3.2) ** 0.90-Large BASDAI 6.5 (1.7) 4.4 (2.7) * 0.84-Large BASFI 6.3 (2.6) 4.1 (3.4) * 0.69-Medium ASDAS 3.6 (1.0) 2.3 (1.2) ** 1.15-Large BASDAS 3.7 (1.1) 2.6 (1.3) * 0.96-Large BASMI 3.6 (1.5) 3.3 (1.3) NS Conclusion: Different methods exist for quantifying inflammation in MRI images of SIJ in axSpA patients. According to our preliminary results, all of them had significant improvements in axSpA patients treated with anti tnf-α. The s-SCAISS index show good responsiveness, with similar features to validated indexes, but with an accuracy assessment of the BME area. References: [1]Defining active sacroiliitis on MRI for classification of axial spondyloarthritis: update by the ASAS MRI working group. Annals of the Rheumatic Diseases 2016;75:1958-1963. [2]Development and validation of SCAISS, a tool for semi-automated quantification of sacroilitis by magnetic resonance in spondyloarthritis. Rheumatol Int. 2018 Oct;38(10):1919-1926. Disclosure of Interests: Cristina Garrido-González: None declared, María del Carmen Castro Villegas: None declared, MLourdes Ladehesa Pineda: None declared, Juan L. Garrido-Castro: None declared, Rafaela Ortega Castro: None declared, Cristina Gonzalez-Navas: None declared, Pedro Zarco-Montejo Speakers bureau: Abbvie, MSD, Novartis, Pfizer., RAQUEL ALMODOVAR Speakers bureau: Abbvie, Celgene, Janssen, Lilly, Novartis, Pfizer. , Angel Bueno: None declared, Luis Miguel Molinero: None declared, Eduardo Collantes Estevez Grant/research support from: ROCHE and Pfizer, Speakers bureau: ROCHE, Lilly, Bristol and Celgene