Quantitative analyses of sonographic images of the parotid gland in patients with Sjögren’s syndrome

The first purpose of this study was to quantify the sonographic images of the salivary gland to differentiate the Sjögren syndrome (SS) group from the non-SS group. We included 132 patients in this study who had been referred to our department because of a suspicion of SS. A total of 91 patients fulfilled the criteria for SS, whereas the remaining 41 patients did not. We placed the regions-of-interest within the lesion. The first purpose was to evaluate which indices obtained by the texture analyses were useful for differentiating the SS group from the non-SS group. The second purpose was to evaluate the relationship between the indices and the degree of severity in the SS group. Out of the several indices evaluated, Hurst coefficients, obtained by fractal analysis, of SS group were found to be significantly lower than those of the non-SS group. Moreover, the Hurst coefficient was associated with the degree of destruction of the parotid gland as assessed by sialography. The Hurst coefficient of a globular stage and an advanced stage were both significantly lower than that of a normal pattern, whereas the Hurst coefficient of a punctate stage was almost similar to that of the normal stage. The Hurst coefficient showed a very weak correlation with the results of either the gum test or serologic tests. (E-mail: chikui@rad.dent.kyushu-u.ac.jp)