AB1077 VALIDATION OF A SIMPLIFIED SPANISH TOOL FOR SEMI-AUTOMATIC QUANTIFICATION OF SACROILIAC INFLAMMATION BY MAGNETIC RESONANCE IN SPONDYLOARTHRITIS (S- SCAISS).
Authors: R. Almodovar, P. Zarco-Montejo, A. Bueno, L. M. Molinero
Journal: Annals of the Rheumatic Diseases (2020)

Background: With the objective to improve quantification of sacroiliitis maintaining a practical perspective, our group developed SCAISS, a semi-automated method to measure bone marrow edema (BME) in MR images from sacroiliac (SI) joints, combining semi-axial and semi-coronal slices [1]. The 2009 ASAS definition of active sacroiliitis was based on standard semi-coronal slices only, perpendicular semi-axial slices being considered but optional [2]. We hypothesized a simplified SCAISS (s- SCAISS) method using only semi-coronal slices. Objectives: To analyze the validity and reliability and feasibility of a simplified Spanish tool for semi-automatic quantification of sacroiliac inflammation by magnetic resonance in spondyloarthritis (s- SCAISS) using a semi-coronal scan instead of combining semi-axial and semi-coronal slices. Methods: The s- SCAISS was designed as an image-processing software. We performed the following analysis: (1) three readers evaluated SI images of 23 patients with axial SpA and various levels of BME severity with the s-SCAISS and SCAISS, and two non-automated methods, SPARCC and Berlin; (2) 20 readers evaluated 12 patients images, also with the three methods. Convergent validity, reliability and feasibility were estimated. Results: The interobserver reliability (ICC and 95% CI) in the three observers’ study was: s-SCAISS = 0.69 (0.490–0.845); SCAISS= 0.770 (0.580–0.889); Berlin = 0.725 (0.537–0.860); and SPARCC = 0.824 (0.671–0.916). In the 20 observers’ study, ICC was: s- SCAISS = 0.66 (0.478–0.863); SCAISS = 0.801 (0.653–0.927); Berlin = 0.702 (0.518–0.882); and SPARCC = 0.790 (0.623–0.923). Spearman correlation coefficient between s- SCAISS _BERLIN was r= 0.712 and s- SCAISS_ SPARCC was r= 0.779 and s- SCAISS _SCAISS was r= 0.90. Similar results showed SCAISS BERLIN and SCAISS_ SPARCC (r= 0.729 and 0.840), respectively. Conclusion: The simplified SCAISS (s-SCAISS) using only semi-coronal slice permits a valid, reliable, and fast calculation of overall BME lesion at the SI joint. References: [1]Zarco P, Almodóvar R, Bueno Á, Molinero LM; SCAISS Study Group.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. [2]Rudwaleit M, Jurik AG, Hermann KGA et al. Defining active sacroiliitis on magnetic resonance imaging (MRI) for classification of axial spondyloarthritis: a consensual approachby the ASAS/OMERACT MRI group. Ann Rheum Dis 2009; 68:1520-7. Acknowledgments: Mireia Moreno (Rheumatology, H. Parc Taulí), Xavier Juanola (Rheumatology, H. Bellvitge), Maite Ventemillas (Radiology, H. Parc Taulí), Victoria Navarro (Rheumatology, H. La Paz), Daniel Bernabeu (Radiology, H. La Paz), Rafael Montero Perez-Barquero (Radiology, H. Reina Sofía de Córdoba), Concha Crespo (Radiology, H. de San Juan de Alicante), Enrique Batlle (Rheumatology, H. de San Juan de Alicante), Carmen Castro Copete (Radiology, H. H. de San Juan de Alicante), Carlos Quiles (Radiology, H. General Universitario de Valencia), Emma Beltrán (Rheumatology, H. del Mar), Fran García Lorente (Rheumatology, H. Universitario de Basurto), Fernando Díez (Radiology, H. Universitario de Basurto), Luis Linares (Rheumatology, H. Virgen de la Arrixaca), Manuel José Moreno Ramos (Rheumatology, H. Virgen de la Arrixaca), Angela Cepero (Radiology, H. H. Virgen de la Arrixaca), Cristina Fernández Carballido (Rheumatology, H. de Elda), Christopher Pack (Radiology, H. de Elda). Disclosure of Interests: RAQUEL ALMODOVAR Speakers bureau: Abbvie, Celgene, Janssen, Lilly, Novartis, Pfizer. , Pedro Zarco-Montejo Speakers bureau: Abbvie, MSD, Novartis, Pfizer., Angel Bueno: None declared, Luis Miguel Molinero: None declared