The novel OMERACT Ultrasound Scoring System for salivary glands changes in patients with Sjögren's syndrome is associated with MRI and salivary flow rates

Objective: To assess the construct validity of the novel OMERACT ultrasound (US) semiquantitative scoring system for morphological lesions in major salivary glands by comparing with MRI and unstimulated whole salivary flow rates (U-WSFRs) in patients with primary Sjögren's syndrome (pSS). Methods: Nine sonographers applied the OMERACT 0-3 grayscale scoring system for parotid (PGs) and submandibular glands (SMGs) in 11 patients with pSS who also had MRIs performed. These were evaluated by two radiologists using a semiquantitative 0-3 scoring system for morphological lesions. The agreement between ultrasound and MRI and the association between U-WSFRs and imaging structural lesions was determined. A score ≥ 2 for both ultrasound and MRI was defined as gland pathology. Results: The prevalence of US morphological lesions in 11 patients with a score ≥2 was 58% for PGs and 76% for the SMGs, while 46% and 41% for the PGs and SMGs, respectively, for MRI. Agreement between OMERACT US scores and MRI scores were 73-91% (Median :82) in right and 73-91% (Median :91) in left PGs, 55-91% (Median :55) in right SMG and 55-82% (Median :55) in left SMG. When relations between the presence of hyposalivation and ≥ 2 score of US were examined, agreement were 91-100% (Median :83) in both PGs and 55-91% (Median :67) in both SMGs. Conclusion: There is moderate to strong agreement between the OMERACT US and MRI scores for major salivary glands in patients with pSS. Similar agreement ratios were observed between the higher OMERACT US scores and presence of hyposalivation.