Full-Field Ultrasound Time-Harmonic Elastography Quantifies Task-Dependent Thoracolumbar Fascia and Multifidus Mechanics During Back Extension
Listed in
This article is not in any list yet, why not save it to one of your lists.Abstract
Purpose
Ultrasound time-harmonic elastography (THE) uses continuous multifrequency vibration and standard-frame-rate ultrasound to generate full-field mechanical maps. We tested whether THE concurrently resolves task-dependent responses in the thin thoracolumbar fascia (TLF) and deeper multifidus muscle (MFM) during back extension.
Methods
Eighteen healthy adults (9 female and 9 male; age 19.4 ± 1.9 years) underwent multifrequency THE (60–80 Hz; 100 frames/s) at rest and during active back extension. Shear wave speed (SWS) and penetration rate (PR), an attenuation-sensitive measure, were quantified in manually defined TLF and MFM regions. Four within-tissue contrasts were tested using paired t tests with Holm adjustment; between-tissue, superficial-tissue-thickness, and sex analyses were exploratory.
Results
Back extension increased SWS in the TLF (+0.43 ± 0.43 m/s; dz = 0.99) and MFM (+0.62 ± 0.23 m/s; dz = 2.73) and decreased PR in the TLF (−1.01 ± 0.54 m/s; dz = −1.88) and MFM (−1.20 ± 0.51 m/s; dz = −2.34); all Holm-adjusted p < 0.001. The SWS increase was 0.19 m/s greater in MFM than TLF (95% confidence interval, 0.01–0.38 m/s; unadjusted p = 0.042), whereas PR changes did not differ between tissues (p = 0.233).
Conclusion
THE simultaneously captured spatially resolved, task-dependent responses in adjacent fascial and muscle tissues using standard-frame-rate acquisition. The findings establish biomechanical sensitivity in healthy adults and support further validation with standardized loading, repeatability testing, and comparison with conventional shear wave elastography.
Clinical trial number
not applicable.
