Salivary gland ultrasonography as a primary imaging tool for predicting efficacy of xerostomia treatment in patients with Sjogren's syndrome

Objective. To evaluate ultrasonography (US) grading of salivary gland disease as a predictor of treatment efficacy for impaired salivary function in xerostomia patients with or without Sjogren's syndrome (SS). Methods. We retrospectively analysed the prognostic importance of salivary US grading in 317 patients (168 with SS and 149 without SS). US images of the parotid and submandibular glands in each patient were individually categorized into grades 0-4 based on the extent of damage to the gland; and the sum total grade of the two gland types on either side was assigned a US score of 0-8 for each patient. The relative importance of US score and demographic and clinical variables was assessed using stepwise multiple regression analysis after various durations of xerostomia treatment. Results. Multiple regression analysis indicated that the baseline US score before treatment was the most important factor [standardized regression coefficient (b) = -0.523, t-statistic (t) = -7.967, P< 0.001] in predicting negative outcomes in SS patients. Treatment duration (b = 0.277, t = 4.225, P< 0.001) was also a significant but less important positive variable. On the other hand, US grading did not effectively predict treatment outcomes in non-SS patients, with treatment duration (b = 0.199, t = 2.486, P = 0.014) and baseline salivary flow rate before treatment (b = -0.172, t = -2.159, P = 0.032) being significant but weak predictors of positive and negative outcome, respectively. Conclusion. Salivary gland US grading may help to predict outcomes of treatment for impaired salivary function in patients with SS.