Sonographic findings of immunoglobulin G₄-related sialadenitis and differences from Sjögren’s syndrome

To evaluate ultrasonic features of the major salivary glands in patients with immunoglobulin G₄-related sialadenitis (IgG₄-RS) and to explore the differences between IgG₄-RS and Sjögren’s syndrome (SS).

We conducted the study in 150 patients with IgG₄-RS and 100 patients with SS. Ultrasonographic variables of the static images of major salivary glands were analysed. An experienced radiologist scored the confidence rating regarding the presence of the characteristic imaging findings using a five-grade rating system. Ultrasonography scores between IgG₄-RS and SS were compared.

The major salivary glands were significantly larger in patients with IgG₄-RS than in the SS group. The main features of ultrasonography of the salivary glands in IgG₄-RS were various hypoechoic lesions and increased colour Doppler signalling. In contrast, the major salivary glands in SS exhibited hyperechoic lines and/or spots and obscuration of the gland configuration. The scores of the summarized sonographic characteristics also showed statistically significant differences between the IgG₄-RS and SS groups.

This study revealed different ultrasonic features of the major salivary glands in patients with IgG₄-RS and SS. The scored sonographic features were helpful in differentiating IgG₄-RS from SS. Consequently, we suggest that ultrasonography of major salivary glands could be a useful imaging procedure in the evaluation of patients suspected of having IgG₄-RS.