Three-Dimensional Mapping of Shear Wave Velocity in Human Tendon: A Proof of Concept Study

Abstract

Ultrasound-based shear wave elastography (SWE) provides the means to quantify tissue mechanical properties in vivo and has proven valuable in detecting degenerative processes in tendons. Its current mode of use is for two-dimensional rendering measurements, which are highly position-dependent. We therefore propose an approach to create a volumetric reconstruction of the mechano-acoustic properties of a structure of interest based on optically tracking the ultrasound probe during free-hand measurement sweeps. In the current work, we aimed (1) to assess the technical feasibility of the three-dimensional mapping of unidirectional shear wave velocity (SWV), (2) to evaluate the possible artefacts associated with hand-held image acquisition, (3) to investigate the reproducibility of the proposed technique, and (4) to study the potential of this method in detecting local adaptations in a longitudinal study setting. Operative and technical feasibility as well as potential artefacts associated with hand-held image acquisition were studied on a synthetic phantom containing discrete targets of known mechanical properties. Measurement reproducibility was assessed based on inter-day and inter-reader scans of the patellar, Achilles, and supraspinatus tendon of ten healthy volunteers and was compared to traditional two-dimensional image acquisition. The potential of this method in detecting local adaptations was studied by testing the effect of short-term voluntary isometric loading history on SWV along the tendon long axis. The suggested approach was technically feasible and reproducible, with a moderate to very good reliability and a standard error of measurement in the range of 0.300–0.591 m/s for the three assessed tendons at the two test-retest modalities. We found a consistent variation in SWV along the longitudinal axis of each tendon, and isometric loading resulted in regional increases in SWV in the patellar and Achilles tendons. The proposed method outperforms traditional two-dimensional measurement with regards to reproducibility and may prove valuable in the objective assessment of pathological tendon changes.

Patellar Tendon Shear Wave Velocity Is Higher and has Different Regional Patterns in Elite Competitive Alpine Skiers than in Healthy Controls

“…US assessments and data processing were performed exactly as described in our validation study, which revealed good interoperator reliability (ICC of 0.736) and very good interday reliability (ICC of 0.904) ( Götschi et al, 2021 ). One assessment was performed for each tendon by an experienced examiner; in total, 4 examiners were involved.…”

“…The tendon was then segmented in the US B-mode volume, and the SWE volume was masked accordingly (3D slicer, version 4.10.2, ( Kikinis et al, 2014 ). To allow analysis of distinct PT regions, the masked SWE reconstruction was divided into three regions with two cuts positioned at a distance of 10 mm from the proximal and distal insertion ( Figure 1B ), analogous to the approach described in our validation study ( Götschi et al, 2021 ). Briefly, the area of interest was identified using landmarks placed during manual segmentation of the volume.…”

“…In particular, tendon imaging requires accurate spatial referencing, as pathological characteristics in structural composition and architecture are typically spatially confined ( Johnson et al, 1996 ; Khan et al, 1996 ; Pearson and Hussain, 2014 ). To overcome these limitations, we have previously implemented and validated an approach for three-dimensional US shear wave velocity mapping ( Götschi et al, 2021 ). The technique allows sampling of larger structures primarily limited by the maximum measurement depth of the system and enables off-line analysis of distinct subregions ( Götschi et al, 2021 ).…”

“…To overcome these limitations, we have previously implemented and validated an approach for three-dimensional US shear wave velocity mapping ( Götschi et al, 2021 ). The technique allows sampling of larger structures primarily limited by the maximum measurement depth of the system and enables off-line analysis of distinct subregions ( Götschi et al, 2021 ).…”

From the Matrix to the Nucleus and Back: Mechanobiology in the Light of Health, Pathologies, and Regeneration of Oral Periodontal Tissues

“…As regenerative stem cell therapies have great therapeutic potential, it is still an active field of research, if such approaches in mechanically exposed tissues such as joints or the periodontium benefit from concomitant mechanical stimulation of the transplanted cells. The so-called "loading history" of the cells might, therefore, play an important role in regenerative stem cell therapies and underscore the pivotal role of MT [365][366][367]. To study these potential influences, Kojima and co-workers presented a micropatterned, polymer-based micropillar research platform that enables the study of FAK and YAP activity in response to mechanical loading.…”