Quantitative Assessment of Salivary Gland Parenchymal Vascularization Using Power Doppler Ultrasound and Superb Microvascular Imaging: A Potential Tool in the Diagnosis of Sjögren’s Syndrome

Abstract

Background: Primary Sjögren’s syndrome is a chronic inflammatoryautoimmune disease. Minor salivary gland biopsy is the goldstandard for the diagnosis of primary Sjögren’s syndrome. Superbmicrovascular imaging, power Doppler ultrasound, and color Dopplerof the salivary glands represent non-invasive, non-irradiating modalityfor evaluating the vascularity of the salivary glands in the diagnosisand follow-up of primary Sjögren’s syndrome.Aims: To evaluate the efficacy of superb microvascular imaging andvascularity index in salivary glands for the sonographic diagnosis ofprimary Sjögren’s syndrome.Study Design: Prospective case-control study.Methods: Twenty participants with primary Sjögren’s syndrome and20 healthy subjects were included in the study. Both parotid glandsand submandibular glands were evaluated by superb microvascularimaging, power Doppler ultrasound, and color Doppler. The diagnosticaccuracy of superb microvascular imaging was compared using thesetechniques.Results: In the patient group, the vascularity index values of superbmicrovascular imaging in parotid glands and submandibular glandswere 3.5±1.66, 5.06±1.94, respectively. While the same values were1.0±0.98 and 2.44±1.34 in the control group (p≤0.001). In the patientgroup, the vascularity index values of power Doppler ultrasoundin parotid glands and submandibular glands were 1.3±1.20 and2.59±1.82, respectively. While the same values were 0.3±0.32 and0.85±0.68 in the control group (p≤0.001). The superb microvascularimaging vascularity index cut-off value for the diagnosis of primarySjögren’s syndrome in parotid glands that maximizes the accuracy was1.85 (area under the curve: 0.906; 95% confidence interval: 0.844,0.968), and its sensitivity and specificity were 87.5% and 72.5%,respectively. While the superb microvascular imaging vascularityindex cut-off value for the diagnosis of primary Sjögren’s syndromein submandibular gland that maximizes the accuracy was 3.35 (areaunder the curve: 0.873; 95% confidence interval: 0.800, 0.946), itssensitivity and specificity were 82.5% and 70%, respectively.Conclusion: Superb microvascular imaging with high reproducibilityof the vascularity index has a higher sensitivity and specificity thanthe power Doppler ultrasound in the diagnosis of primary Sjögren’ssyndrome. It can be a noninvasive technique in the diagnosis ofprimary Sjögren’s syndrome when used with clinical, laboratory andother imaging methods.