Effectiveness of shear wave elastography for assessing major salivary gland involvement in ankylosing spondylitis

To use shear wave elastography (SWE) in the evaluation of salivary glands in patients with ankylosing spondylitis (AS) who present with sicca symptoms.

This was a prospective controlled study of patients diagnosed with AS and exhibiting sicca symptoms (study group) and of healthy volunteers (control group). The levels of antinuclear, anti-Ro, and anti-La antibodies were determined in blood samples. In both groups, parotid and submandibular glands were evaluated by ultrasound and tissue stiffness was determined by SWE. Intraclass correlation coefficients were used in order to assess reliability. The differences between the two groups were assessed by statistical methods, and a ROC curve analysis was performed to determine the predictive values.

A total of 66 patients with AS and 71 healthy volunteers were included in the study. There were no significant differences between the groups in terms of age or sex (p > 0.05). The intraand inter-rater reliability of SWE were good for the parotid gland (0.81-0.85 and 0.80, respectively) and for the submandibular gland (0.85-0.88 and 0.80, respectively). Statistically significant differences were found. Tissue stiffness in the parotid and submandibular glands, as determined by SWE, was significantly greater in the study group than in the control group (p < 0.05).

Although there was no histopathological correlation in the parotid and submandibular salivary glands of patients with AS and sicca symptoms compared with the healthy volunteers, quantitative measurements showed greater tissue stiffness in the former group. In patients with AS, SWE guides salivary gland biopsy, which is the gold standard for diagnosing Sjögren's syndrome.