Ultrasound scoring systems affect the distribution of sialadenitis scores in Sjögren’s syndrome: an inter-system reproducibility study

Abstract

Objective Salivary gland ultrasonography (SGUS) is commonly employed in the diagnosis and follow-up of patients with Sjögren’s syndrome (SS) and multiple scoring systems have been developed to quantify the grade of sialadenitis of major salivary glands (SG). Their diagnostic performance seems overall comparable, however, the parameters evaluated by the various systems are different. The objective of this study was to compare how four different scoring systems affect the distribution of sialadenitis grades. Methods One hundred and three SGUS images from 26 SS patients were blindly scored by two investigators according to the De Vita, Salaffi, Milic and OMERACT scoring systems in independent sessions. Results The distribution of SGUS images according to De Vita, Salaffi, Milic and OMERACT systems was significantly different. At post-hoc analysis, Milic system performed differently compared to the De Vita (p<0.0001), OMERACT (p<0.0001) and Salaffi (p<0.0001) systems, showing a relative overestimation of sialadenitis grade. Conclusion Milic scoring system showed to relatively overestimate the grade of sialadenitis compared to De Vita, Salaffi and OMERACT systems. Although all scoring systems seem to be comparable in terms of diagnostic accuracy, in the prospect of selecting one system to be potentially included in future versions of SS classification criteria, it is important to compare their ability to classify SGUS images among the various degrees of sialadenitis.