Quantitative elastography of Achilles tendon using Shear Wave Elastography (SWE): correlation with zonal anatomy

Abstract

Introduction:To evaluate the feasibility and reproducibility of quantitative ultrasonic measurement of normal Achilles tendon (AT) stiffness, using supersonic shear wave elastography (SWE) in correlation with its zonal anatomy. Materials and methods: Thirty tendons (8 women, 7 men) (mean age, 29,5 years; age range, 24-51 years) underwent morphologic and SWE measurements. The quantitative measurements of the tendon in four points (musculo-tendinous junction, tendinous body, pre-insertional area and enthesis) according to zonal anatomy were performed by two MSK radiologists and respectively expressed in terms of mm and Young's modulus (kPa). Inter-observer reproducibility was also assessed. Results: The SWE measures show higher stiffness for the sagittal position of the US than in axial plane in all four AT levels (p<0.0382). Moreover, SWE measurements were significantly higher in dorsal flexion than in plantar flexion in all four AT levels (p<0.0317). Last, SWE visco-elasticity increases significantly from the musculotendinous junction to the pre-insertional and enthesis area (p<0.001) in plantar flexion. There was no significant interobsever difference for morphologic measurements and for stifness measure-ments in plantar and dorsal flexions (p>0.075). Conclusion: Quantitative measurement of normal AT using SWE is reproductible almost in plantar flexion, and increase from musculo-tendinous junction to enthesis and could now be integrated in our routine AT ultrasound exploration. Level of evidence: II.

Quantitative Weight Bearing and non-weight Bearing Measures of Stiffness in the Achilles Tendon and Gastrocnemius Muscle

“…A comparative study utilising shear wave elastography (SWE) of four zones (musculo-tendinous junction, body, pre-insertional and enthesis) of the Achilles tendon complex with the foot dorsiflexed and planatarflexed have indicated comparative findings to our study (36). Petitpierre et al 2018 (36) found stiffness in the Achilles complex increased from its musculo-tendinous junction to its enthesis. Even though the study sample size was smaller than ours, the results support the findings of our study adding weight to the case for tendon assessment loaded and unloaded.…”

“…Where previously too much stiffness has been associated with bony injuries and too little stiffness with soft tissue injuries (34,35). A comparative study utilising shear wave elastography (SWE) of four zones (musculo-tendinous junction, body, pre-insertional and enthesis) of the Achilles tendon complex with the foot dorsiflexed and planatarflexed have indicated comparative findings to our study (36). Petitpierre et al 2018 (36) found stiffness in the Achilles complex increased from its musculo-tendinous junction to its enthesis.…”

Sonoelastography of Normal Canine Common Calcaneal Tendon: Preliminary Results

“…The reason of that choice relies on the fact that some authors suggest collecting shear wave elastography measurements in m/s since in anisotropic tissues (as tendons) shear waves velocity may not exactly correspond to the Young Modulus, 11 but many studies were performed using the only kPa as measure unit to assess human calcaneal tendon elasticity. 22,24 Since in veterinary medicine, there are no available data about the application of this technique on tendons, in this study, measurements have been collected with both measurement units and these preliminary results suggest that kPa seems to be slightly more reproducible than m/s. About intra-observer repeatability, this was considered excellent for both operators in each common calcaneal tendon portion examined, thus providing that the single measurements are highly repeatable.…”

“…These data are coherent to what is described in human medicine about calcaneal tendon elasticity; Petitpierre and colleagues described the same results in their study, assessing that this could be explained by the histological tendon structure which is different from different sections of the same tendon. 22 Physiologically a tendon is composed of collagen fibres and striated muscle fibres smaller quantities than in muscle in its musculotendinous junction, 30 while the healthy body and the pre-insertional portion are characterized by type 1 collagen and a few elastic fibres in a ground substance with cells and water. The enthesis is, on the contrary, characterized by the presence of fibrocartilage, 31 thus explaining the progressive increase of stiffness from the musculotendinous junction to the tendon enthesis.…”

“…18 In human medicine, shear wave elastography is considered a feasible tool to investigate calcaneal tendon mechanical properties and its alteration in the case of tendinopathies, with high specificity. 12,[19][20][21][22][23][24] To our knowledge, no published data are available about the possible application of this elastography technique on canine common calcaneal tendon.…”