Ultrasonographic evaluation of lacrimal glands in patients with primary Sjögren's syndrome.

Abstract

This study focused on distinguishing the characteristic ultrasonographic findings of lacrimal glands in primary Sjögren's syndrome (pSS) from those in idiopathic sicca syndrome. We aimed to set up a semi-quantitative scoring system of lacrimal gland ultrasonography (LGUS) for patients with pSS. Fifty-six patients with pSS and 40 patients with idiopathic sicca syndrome were evaluated. Lacrimal glands were examined with ultrasonography using area, major/minor axis length, and five components (presence of intraglandular branch of lacrimal artery, inhomogeneity, hyperechoic bands, hypoechoic areas, and delineation). Except for the area and maximal/minimal length of lacrimal glands, other components were classified as dichotomous variables (present or absent). Using the receiver operating characteristics curve, we inferred the most appropriate combination of LGUS scoring for pSS diagnosis. Patients with pSS had a higher proportion of intraglandular branch of lacrimal artery (70.5% vs. 42.5%, p<0.001), inhomogeneity (72.3% vs. 46.3%, p<0.001), and hyperechoic bands (56.2% vs. 37.5%, p=0.016) than patients with idiopathic sicca syndrome. LGUS A, which represents the summation of one point assigned for the presence of intraglandular branch of lacrimal artery and one for inhomogeneity, was the most suitable diagnostic criterion (area under curve = 0.724, 95% confidence interval 0.620-0.828). If both sides have a score of 2, it results in a total of 4 points. With a cut-off value of 3 out of 4 points, LGUS A had 60.7% sensitivity, 71.1% specificity, 60.7% positive predictive value, and 72.5% negative predictive value. Semi-quantitative scoring of LGUS was useful when distinguishing patients with pSS from those with idiopathic sicca syndrome. The combination of intraglandular branch of lacrimal artery and inhomogeneity on both sides was most suitable for classifying pSS using LGUS.