Disease activity in patients with synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome: the utility of the SPARCC MRI scoring system for assessment of axial spine involvement

Objective The aim of this study is to investigate the relationship between spinal MRI findings with disease activity and other clinical and serological parameters, and to determine the importance of MRI scoring system in evaluating disease activity of SAPHO syndrome. Methods Thirty patients with SAPHO syndrome underwent clinical, laboratory and MRI evaluation at baseline, 3 months, 6 months and 1 year. Magnetic resonance images were analysed using modified Spondyloarthritis Research Consortium of Canada (SPARCC) scoring system. Correlations between MRI score and clinical and laboratory parameters were analysed using Spearman's rank correlation test. Results Persistent improvement was observed after 12 months in terms of total modified SPARCC scores (37(12,59) vs. 23(5,45) at baseline and 12 months, p<0.05). Total modified SPARCC scores showed Spearman correlations with hypersensitive C-reaction protein (hs-CRP), ankylosing spondylitis disease activity score (ASDAS) and bath ankylosing spondylitis metroloty index (BASMI) at baseline, 3 months, 6 months and 12 months (p varied from <0.001 to <0.05, and r varied from 0.418 to 0.601). Modified SPARCC scores of spine joint, as the largest contribution to the total scores with the mean score of 12(5,30) after 12 months vs. 26 (12,40) at baseline. Conclusion The modified SPARCC score proposed in this study exhibits promising potential in the evaluation of extensive radiographic damage in SAPHO and the reflection the disease activity. Our study suggests that MRI could be used together with other parameters of disease activity in the assessment of symptomatic SAPHO patients with spine involvement.