Patient-based reliability of the Outcome Measures in Rheumatology (OMERACT) ultrasound scoring system for salivary gland assessment in patients with Sjogren's syndrome

Background. To assess the reliability of the consensually agreed US definitions of major salivary gland lesions and the US scoring system for salivary gland assessment in patients with SS. Methods. Nine experienced sonographers scanned and read the US images of both parotid glands (PGs) and submandibular glands (SMGs) in eight patients with primary and secondary SS in two rounds. A consensually agreed four-grade semi-quantitative scoring was applied in B-mode for morphological lesions: grade 0, normal; grade 1, mild inhomogeneity without anechoic or hypoechoic areas; grade 2, moderate inhomogeneity with focal anechoic or hypoechoic areas; grade 3, severe inhomogeneity with diffuse an- or hypoechoic areas occupying the entire gland or fibrous gland. The presence or absence of typical SS lesions, i.e. the Sjogren's signature, was scored binary. Intra- and inter-reader reliabilities were computed using weighted and unweighted Cohen's and Light's kappa coefficients. Results. The mean prevalence of grades 0-3 in PG were 43, 17, 23 and 31% and 28, 14, 33 and 32% for the SMGs, respectively. The weighted kappa for intrareader reliability ranged from 0.44 to 1 for grading and 0.64 to 1 for the Sjogren's signature of PG and 0.59 to 1 and -0.09 to 0.6 for SMGs, respectively. The interreader reliability kappa for grading in PG was 0.62 (95% CI 0.47, 0.74) and for Sjogren's signature it was 0.36 (95% CI 0, 0.43); in SMG it was 0.62 (95% CI 0.47, 0.72) and 0.03 (95% CI 0, 0.07) respectively. Conclusions. The consensually agreed novel US scoring system for major salivary gland lesions showed substantial intra- and interreader reliability in patients with SS. The reliability of the Sjogren's signature was moderate.

Automated summary

The consensually agreed US definitions and scoring system for major salivary gland assessment showed high reliability in patients with SS, while the reliability of the Sjogren's signature was moderate.