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

## TL;DR

This study shows that shear wave elastography can detect increased salivary gland stiffness in ankylosing spondylitis patients with dryness symptoms, potentially guiding biopsies.

## Contribution

Demonstrates the effectiveness of shear wave elastography in assessing salivary gland involvement in ankylosing spondylitis.

## Key findings

- Salivary glands in AS patients with sicca symptoms showed significantly higher stiffness using SWE.
- SWE had good intra- and inter-rater reliability for measuring gland stiffness.
- SWE could guide biopsies for diagnosing Sjögren’s syndrome in AS patients.

## Abstract

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.