To evaluate the multiobserver reliability of salivary gland ultrasonography (SGUS) for scoring greyscale (GS) parenchymal inhomogeneity and parenchymal color Doppler (CD) signal in patients with established primary Sjögren syndrome (pSS).
The study comprised 2 multiobserver reliability assessments in patients with pSS in 2 European centers. The first reliability exercise was performed on 24 patients with pSS and 8 controls who were independently evaluated with GS and CD US by 5 observers at the Institute of Rheumatology, Belgrade, Serbia. The second reliability exercise was carried out on 10 patients with pSS who were independently assessed with GS and CD US by 8 observers at the Hospital G.U. Gregorio Marañón, Madrid, Spain. SGUS parenchymal inhomogeneity and parenchymal CD signal were semiquantitatively scored using a 4-grade scoring system. The multiobserver agreement was calculated by the overall agreement and Light's κ statistics.
A total of 640 SGUS examinations were performed in the first reliability exercise and a total of 320 examinations in the second reliability exercise. Multiobserver reliability was good (κ = 0.71-0.79) to excellent (κ = 0.81-0.82) for GS parenchymal inhomogeneity in both exercises. There was a moderate (κ = 0.53-0.58) to good (κ = 0.70) multiobserver reliability for parenchymal CD signal in the first exercise. However, there was no agreement or only a fair agreement (κ = 0.03-0.29) for parenchymal CD signal in the second exercise.
US may be a reliable technique in the multiobserver scoring of GS parenchymal inhomogeneity of major SG in patients with established pSS. CD scoring of SG needs further standardization to be used in multicenter studies.