AB0520\u2005A COMPARISON OF SHEAR WAVE ELASTOGRAPHIC FINDING OF SUBMANDIBULAR GLANDS IN PATIENTS WITH EARLY-STAGE AND NON-SJÖGREN’S SYNDROME

Abstract

Background Salivary gland (SG) ultrasonography proved valuable for assessing SG involvement in Sjögren’s syndrome (SS) and seemed to exhibit good diagnostic properties. We have reported that the submandibular gland ultrasonography (SGUS) is a useful noninvasive and inexpensive procedure for the evaluation of the structural changes of SG in SS (ISSS 2002, EULAR 2009, EULAR 2012, EULAR 2015). However, our previously study demonstrated that although SGUS findings were useful for the diagnosis of SS with low salivary flow they were not for early stage SS with normal salivary flow (EULAR 2016). Recently, we reported that the tissue elasticity was decreased due to structural changes in the SG at the advanced stage of the disease and that the shear wave elastography (SWE) is useful to distinguish pathological changes of the SG between early stage with normal salivary flow and advanced stage (EULAR2018). The present study we demonstrated that the tissue elasticity was increased due to inflammation and high viscosity in the SG at the early stage of SS with normal salivary flow comparing that in non-SS patients, but was decreased due to structural changes in the SG at the advanced stage of the disease. The SWE may be a useful tool for elucidation of early stage pathological changes of the SG when salivary gland functions are not impaired in SS. Objectives The aim of this study was to elucidate the usefulness of SWE in early-stage SS patients. Methods Seventeen non-SS patients and eighty patients who fulfilled the American College of Rheumatology (ACR)/European League Against Rheumatism (EULAR) classification criteria for SS were studied. SS patients were divided into three groups according to salivary flow using gum test (VL/SS: <5mL/10min. (n=33), L/SS: 5-10mL/10min. (n=32) and N/SS: ≧10mL/10min. (n=15)). All patients were examined SGUS by a single investigator who was blinded to device (TUS-A300; Canon Medical Systems, Tokyo, Japan) with a linear transducer (7.5-10MHz). The examination consisted of conventional B-mode US (US staging score), pulsed wave Doppler US (PD grading score) and SWE with quantitative assessment. US staging scores were assessed by glandular size, inhomogeneity and contrast of diagastric muscle (stage 0 to 3). PD grading scores were graded by pulsed wave pattern in pulsed wave Doppler US at the internal SG facial arteries (grade 0 to 2). With the region-of-interest (ROI) placed over the stiffest areas of the lesion on SWE, the quantitative mean of the elasticity values were measured by shear wave velocity (Vs: m/s) and elasticity (E: kPa) for each lesion. Results The Vs and E values were correlated with US staging score (r=-0.56, p<0.001, r=-0.58, p<0.001) and PD grading score (r=-0.51, p<0.001, r=-0.52, p<0.001) in all patients. There was no significant difference between non-SS and N/SS in early-stage SS by US staging score (0.77±0.90 vs 1.20±0.86) and PD grading score (0.18±.053 vs 0.53±0.19). However, the values of Vs and E were highest in N/SS as compared with all groups, and significantly higher in N/SS than in non-SS (Vs: 1.73±0.18 vs 2.03±0.28m/s, p<0.01, E: 9.38±1.17 vs 12.73±3.63kPa, p<0.01). Conclusion The present study we demonstrated that the tissue elasticity was increased due to inflammation and high viscosity in the SG at the early stage of SS with normal salivary flow comparing that in non-SS patients. The SWE may be a useful tool for the differential diagnosis between patients with non-SS and early-stage SS with normal salivary flow in contrast to conventional SGUS. Disclosure of Interests None declared