US is a valuable tool for detecting salivary gland abnormalities in pSS. Its reliability has been poorly investigated and there is considerable variation in the definition of US abnormalities. Further studies are required to validate and standardize the US definition of salivary gland in pSS.

We show high diagnostic accuracy of a novel US scoring system of salivary glands (0-48) in patients with primary SS comparable to invasive methods, i.e., scintigraphy and salivary gland biopsy.

We demonstrate the high diagnostic value of a novel US score for parenchymal inhomogeneity (0-12) that could serve as a useful single US criterion in the evaluation of salivary gland involvement in primary SS.

US finding of major salivary gland involvement could replace sSC in AEC for the diagnosis of pSS.

ObjectivesUltrasonography (US) is sensitive for detecting echostructural abnormalities of the major salivary glands (SGs) in primary Sjögren’s syndrome (pSS). Our objectives were to define selected US-SG echostructural abnormalities in pSS, set up a preliminary atlas of these definitions and evaluate the consensual definitions reliability in both static and acquisition US-SG images.MethodsInternational experts in SG US in pSS participated in consensus meetings to select and define echostructural abnormalities in pSS. The US reliability of detecting these abnormalities was assessed using a two-step method. First 12 experts used a web-based standardised form to evaluate 60 static US-SG images. Intra observer and interobserver reliabilities were expressed in κ values. Second, five experts, who participated all throughout the study, evaluated US-SG acquisition interobserver reliability in pSS patients.ResultsParotid glands (PGs) and submandibular glands (SMGs) intra observer US reliability on static images was substantial (κ > 0.60) for the two main reliable items (echogenicity and homogeneity) and for the advised pSS diagnosis. PG inter observer reliability was substantial for homogeneity. SMGs interobserver reliability was moderate for homogeneity (κ = 0.46) and fair for echogenicity (κ = 0.38). On acquisition images, PGs interobserver reliability was substantial (κ = 0.62) for echogenicity and moderate (κ = 0.52) for homogeneity. The advised pSS diagnosis reliability was substantial (κ = 0.66). SMGs interobserver reliability was fair (0.20< κ ≤ 0.40) for echogenicity and homogeneity and either slight or poor for all other US core items.ConclusionThis work identified two most reliable US-SG items (echogenicity and homogeneity) to be used by US-SG trained experts. US-PG interobserver reliability result for echogenicity is in line with diagnosis of pSS.