SWE of Salivary Glands in Sjögren's Syndrome: Stiffness Patterns

Physical Principle of SWE

Shear-wave elastography (SWE) is a method for non-invasive quantitative assessment of tissue stiffness. A modified transducer sends push pulses (focused acoustic energy), causing microscopic tissue displacement and inducing perpendicular shear waves, which are tracked by diagnostic imaging. The wave propagation speed is expressed in m/s or kPa: in stiffer tissues, the speed of shear waves is higher (Hagen-Ansert, 2023; Griffith, 2025).

Interpretation of Color Maps

SWE color maps provide quantitative units. In the examples provided in the fragments, stiff tissues are displayed in red, while soft tissues are shown in blue. For instance, a normal Achilles tendon shows a stiffness of 497 kPa (red), whereas pronounced tendinosis shows 133 kPa (blue, softer heterogeneous tissue) (Griffith, 2025). This illustrates that the stiffness pattern depends on the structural condition of the tissue.

Applicable to Salivary Glands in Sjögren's Syndrome

Specific threshold values, patterns, or diagnostic criteria of SWE for salivary glands in Sjögren's syndrome are absent in the available source fragments [clarification needed]. Providing specific cut-offs without a verified source is inadmissible.

General Methodological Notes

Analogous to other organs, it should be considered that SWE threshold values vary between ultrasound system manufacturers. For example, for the thyroid gland, a single consensus on stiffness ranges for differentiating benign and malignant nodules is absent, and proposed cut-offs vary widely (EFSUMB, 2026). This underscores the necessity of using reference values specific to the particular device and method.