Functional Evaluation of Major Salivary Glands Using Viscosity PLUS and 2D Shear-Wave PLUS Elastography Techniques in Healthy Subjects—A Pilot Study

Abstract

Biological soft tissues are characterized by viscoelastic properties. The propagation of shear waves within tissues is influenced by both elasticity, which is linked to the shear wave speed, and viscosity, which is linked to the shear wave dispersion. This study aimed to functionally assess the parotid glands (PG) and submandibular glands (SMG) in a group of 40 healthy subjects using the novel Viscosity PLUS (Vi.PLUS) and 2D Shear-Wave Elastography PLUS (2D-SWE.PLUS) techniques. The viscosity and stiffness of PG and SMG were measured before and after gustatory stimulation with a sialagogue agent (commercially available lemon juice) using the new SuperSonic MACH 30 ultrasound system equipped with a curvilinear C6-1X transducer. PG presented a mean basal viscosity and elasticity of 2.10 ± 0.19 Pa.s and 11.32 ± 1.91 kPa, respectively, which significantly increased poststimulation to 2.39 ± 0.17 Pa.s (p < 0.001) and 12.58 ± 1.92 kPa (p < 0.001), respectively. SMG did not present statistically increased values of viscosity and elasticity following stimulation (2.31 ± 015 Pa.s vs. 2.37 ± 0.18 Pa.s, p = 0.086, and 10.40 ± 1.64 kPa vs. 10.90 ± 1.98 kPa, p = 0.074, respectively). Vi.PLUS measurements presented a good positive correlation with 2D-SWE.PLUS values for PG and SMG, before and after stimulation. Gender and BMI were not confounding factors for these two parameters. Vi.PLUS represents an innovative non-invasive imaging technique that, together with 2D-SWE.PLUS proves to be useful in functionally assessing the major salivary glands in healthy subjects.

Viscosity Plane-Wave UltraSound (Vi PLUS) in the Evaluation of Thyroid Gland in Healthy Volunteers—A Preliminary Study

“…First, we did not assess intra- and interobserver reproducibility, all measurements being performed by a single observer. However, recent studies published by our group [ 20 , 25 ] have shown good intra- and interobserver reproducibility of applying Vi PLUS method in calculating viscosity to other soft tissues with similar depth to thyroid parenchyma. Second, no blood tests were performed to confirm normal thyroid function for the healthy volunteers.…”

“…To date, only a few studies have evaluated the potential of this recent ultrasound technique. Muntean et al [ 9 , 20 ] prospectively evaluated the capability of Vi PLUS in establishing reference values for the parotid and submandibular glands in healthy subjects and also evaluated the functional changes in major salivary glands in healthy subjects. Popa et al [ 5 ] studied the role of viscosity using Vi PLUS mode in patients with liver steatosis, fibrosis, and inflammation in patients with non-alcoholic fatty liver disease (NAFLD) and concluded there is an independent association between viscosity values and liver stiffness values.…”

Clinical and radiographic follow-up after the Wilkie procedure at 28 years: A case report

“…Muntean et al. [21] through literature review, reported normal parotid gland assessment to result in a range of elasticity values from 5.39 to 26 kPa.…”

Multiparametric ultrasound-based assessment of overt hyperthyroid diffuse thyroid disease

“…Multiparametric ultrasound evaluation is used in the differential diagnostic of focal liver ( 10 ) and pancreatic lesions, breast ( 11 , 12 ), thyroid ( 13 – 17 ), cervical lymph nodes ( 18 )or testicular ( 19 – 21 ) nodular disease. Combining the information from gray scale US, doppler, elastography and contrast enhanced ultrasound do offer valuable information also in diffuse diseases such as salivary gland ( 22 ) or liver ( 23 , 24 ).…”