Assessment of salivary gland involvement in primary Sjögren's syndrome using ultrasound viscoelasticity imaging.

Abstract

To investigate the value of ultrasound (US) viscoelasticity imaging in assessing salivary gland involvement in primary Sjögren's syndrome (pSS) by quantifying tissue elasticity and viscosity parameters, and to determine their individual and combined diagnostic efficacy for pSS. This prospective study enrolled 62 pSS patients and 62 age- and sex-matched negative control (NC) subjects. All participants underwent US viscoelasticity imaging of the parotid and submandibular glands, with mean elasticity (Emean) and mean viscosity (Vmean) measured and compared between groups. Salivary gland ultrasound (SGUS) was graded using the OMERACT system, and its correlation with viscoelasticity parameters was analyzed. Diagnostic performance for pSS was assessed using multiple metrics, focusing particularly on the area under the receiver operating characteristic curve (AUC). The pSS group exhibited significantly elevated salivary gland Emean and Vmean compared to the NC group (all p < 0.001). Both parameters showed strong positive correlations with each other (r = 0.465-0.632, all p < 0.001) and with SGUS grades (r = 0.563-0.819, all p < 0.001). For pSS diagnosis, the combination of Emean and Vmean achieved the highest AUC of 0.929, sensitivity of 87.1%, specificity of 85.5%, and accuracy of 86.3%. US viscoelasticity imaging is a reproducible, noninvasive tool for pSS assessment. Increased salivary gland elasticity and viscosity correlate with disease severity, and their combination provides superior diagnostic accuracy, offering a promising alternative for pSS diagnosis. QuestionThe role of US viscoelasticity imaging in quantitatively evaluating salivary gland involvement and improving clinical diagnostic performance for pSS remains uncertain. FindingsSalivary glands in pSS patients exhibit significantly increased elasticity and viscosity, with the combination demonstrating superior diagnostic performance and strong correlation with disease severity. Clinical relevanceUS viscoelasticity imaging provides a reliable, noninvasive diagnostic alternative for pSS, enabling quantitative gland assessment while potentially reducing reliance on invasive procedures.