Locoregional Variability and Measurement Reliability of Tongue Biomechanical Properties Assessed by Shear-Wave...

To characterize locoregional variability of tongue biomechanical properties using shear-wave elastography (SWE) and quantitative ultrasound markers and to evaluate intra- and inter-rater reliability in healthy young adults.

In this cross-sectional study, 86 healthy young adults underwent standardized ultrasound assessment of anterior and posterior tongue regions. Tissue stiffness was measured using SWE. Quantitative ultrasound parameters included echo intensity (EI) and two acoustic attenuation markers (tissue attenuation imaging index and tissue scatter distribution imaging [TSI]). Measurements were acquired in sagittal and coronal imaging planes. Intra- and inter-rater reliability were evaluated using intra-class correlation coefficients with 95% confidence intervals, Bland-Altman analysis and measurement error metrics. Associations with anthropometric variables were evaluated using correlation and multivariable regression analyses. Locoregional differences between anterior and posterior tongue regions were analyzed.

Significant locoregional differences were observed between tongue regions. The posterior region demonstrated higher stiffness, EI and TSI index values across both planes, whereas attenuation index values were lower. Intra-rater reliability was good to excellent for all markers, with strong linear associations between repeated measures. Inter-rater reliability ranged from moderate to good. SWE, EI and attenuation index obtained in the sagittal plane demonstrated the highest reliability.

Quantitative ultrasound demonstrates intrinsic locoregional heterogeneity in tongue biomechanical properties in healthy young adults. SWE and EI in sagittal plane acquisitions provide the most reliable measurements. These findings support methodological standardization and provide preliminary methodological benchmarks for future investigations of tongue biomechanics in clinical populations.