Inhomogeneity of the lacrimal glands is the most important ultrasound finding in primary Sjögren's syndrome: a comprehensive study with 2D-Shear Wave Elastography.

Abstract

Aim: This study aimed to compare the diagnostic performance,  interobserver reliability, and practical utility of two lacrimal gland ultrasound (LGUS) scoring systems - LGUS score I, a complex multi-parameter score, and LGUS score II, a simplified single-parameter score - for diagnosing primary Sjögren's syndrome (pSS). The additional role of two-dimensional shear wave elastography (2D-SWE) in assessing lacrimal gland stiffness was also evaluated.

Material and methods: This observational, cross-sectional study included 35 pSS patients and 35 age- and sex-matched healthy controls. LGUS score I incorporated four grey-scale ultrasound parameters, while LGUS score II relied solely on glandular homogeneity. Both scoring systems were evaluated for diagnostic accuracy and interobserver agreement. SWE measurements of lacrimal gland elasticity were also recorded and compared between groups.

Results: LGUS score II achieved diagnostic performance comparable to LGUS score I, with areas under the curve (AUC) of 0.831 and 0.829, respectively (p=0.961). Sensitivity was higher for LGUS score II (94.29%) than for LGUS score I (85.70%), with both scores demonstrating identical specificity (68.57%). Interobserver agreement was good for LGUS score II (κ=0.707) and moderate for LGUS score I (κ=0.553). SWE measurements showed no significant differences in mean elasticity values between the pSS and control groups (8.78±2.03 kPa vs. 9.27±2.07 kPa, p=0.158).

Conclusion: LGUS score II (glandular homogeneity) offers a reliable, time-efficient diagnostic approach for pSS, providing similar accuracy to the more complex LGUS score I with enhanced interobserver reliability, while the potential of 2D-SWE remains limited by methodological inconsistencies and requires further standardization.