Biomechanical properties of the calcaneal tendon in vivo assessed by transient shear wave elastography

OBJECTIVEEvaluation of living tissue elasticity has wide applications in disease characterization and prognosis prediction. Few previous ex vivo attempts have been made to characterize spinal cord elasticity (SCE). Recently, tissue elasticity assessment has been clinically feasible using ultrasound shear wave elastography (SWE). The current study aims to characterize SCE in healthy dogs, in vivo, utilizing SWE, and to address SCE changes during compression.METHODSTen Greyhound dogs (mean age 14 months; mean weight 14.3 kg) were anesthetized and tracheally intubated, with hemodynamic and neurological monitoring. A 3-level, midcervical laminectomy was performed. SCE was assessed at baseline. Next, 8- and 13-mm balloon compressions were sequentially applied ventral to the spinal cord.RESULTSThe mean SCE was 18.5 ± 7 kPa. Elasticity of the central canal, pia mater, and dura mater were 21.7 ± 9.6 kPa, 26.1 ± 14.8 kPa, and 63.2 ± 11.5 kPa, respectively. As expected, the spinal cord demonstrated less elasticity than the dura mater (p < 0.0001) and pia mater (trend toward significance p = 0.08). Notably, the 13-mm balloon compression resulted in a stiffer spinal cord than at baseline (233 ± 73 kPa versus 18.5 ± 7 kPa, p < 0.0001) and 8-mm balloon compression (233 ± 73 kPa versus 185 ± 68 kPa, p < 0.048).CONCLUSIONSIn vivo SCE evaluation using SWE is feasible and comparable to earlier reports, as demonstrated by physical sectioning of the spinal cord. The compressed spinal cord is stiffer than a free spinal cord, with a linear increase in SCE with increasing mechanical compression. Knowledge of the biomechanical properties of the spinal cord including SCE has potential implications for disease management and prognosis.

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Reverberant Shear Wave Elastography: A Multi-Modal and Multi-Scale Approach to Measure the Viscoelasticity Properties of Soft Tissues

Frontiers in Physics ◽

10.3389/fphy.2020.606793 ◽

2021 ◽

Vol 8 ◽

Author(s):

Juvenal Ormachea ◽

Fernando Zvietcovich

Keyword(s):

Wave Propagation ◽

Shear Wave ◽

Acoustic Waves ◽

Guided Waves ◽

Soft Tissues ◽

Ex Vivo ◽

Surface Acoustic Waves ◽

Shear Wave Elastography ◽

Biomechanical Properties

There are a variety of approaches used to create elastography images. Techniques based on shear wave propagation have received significant attention. However, there remain some limitations and problems due to shear wave reflections, limited penetration in highly viscous media, requirements for prior knowledge of wave propagation direction, and complicated propagation in layers where surface acoustic waves and guided waves are dominant. To overcome these issues, reverberant shear wave elastography (RSWE) was proposed as an alternative method which applies the concept of a narrow-band diffuse field of shear waves within the tissue. Since 2017, the RSWE approach has been implemented in ultrasound (US) and optical coherence tomography (OCT). Specifically, this approach has been implemented in these imaging modalities because they are similar in image formation principles and both share several approaches to estimate the biomechanical properties in tissues. Moreover, they cover different spatial-scale and penetration depth characteristics. RSWE has shown promising results in the elastic and viscoelastic characterization of multiple tissues including liver, cornea, and breast. This review summarizes the 4-year progress of the RSWE method in US and OCT. Theoretical derivations, numerical simulations, and applications in ex vivo and in vivo tissues are shown. Finally, we emphasize the current challenges of RSWE in terms of excitation methods and estimation of biomechanical parameters for tissue-specific cases and discuss future pathways for the in vivo and in situ clinical implementations.

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Feasibility of Reverberant Shear Wave Elastography for In Vivo Assessment of Skeletal Muscle Viscoelasticity

2020 IEEE International Ultrasonics Symposium (IUS) ◽

10.1109/ius46767.2020.9251504 ◽

2020 ◽

Author(s):

Estefano Machado ◽

Stefano E. Romero ◽

Gilmer Flores ◽

Benjamin Castaneda

Keyword(s):

Skeletal Muscle ◽

Shear Wave ◽

Shear Wave Elastography ◽

In Vivo Assessment

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Effect of Rest Duration Between Static Stretching on Passive Stiffness of Medial Gastrocnemius Muscle In Vivo

Journal of Sport Rehabilitation ◽

10.1123/jsr.2018-0376 ◽

2020 ◽

Vol 29 (5) ◽

pp. 578-582

Author(s):

Masatoshi Nakamura ◽

Shigeru Sato ◽

Ryosuke Kiyono ◽

Nobushige Takahashi ◽

Tomoichi Yoshida

Keyword(s):

Elastic Modulus ◽

Shear Wave ◽

Repeated Measures ◽

Shear Wave Elastography ◽

Muscle Stiffness ◽

Medial Gastrocnemius ◽

Static Stretching ◽

Shear Elastic Modulus ◽

Before And After

Context: In clinical and sports settings, static stretching (SS) is usually performed to increase range of motion (ROM) and decrease passive muscle stiffness. Recently, the shear elastic modulus was measured by ultrasonic shear wave elastography as an index of muscle stiffness. Previous studies reported that the shear elastic modulus measured by ultrasound shear wave elastography decreased after SS, and the effects of SS on shear elastic modulus were likely affected by rest duration between sets of SS. Objective: To investigate the acute effects of SS with different rest durations on ROM and shear elastic modulus of gastrocnemius and to clarify whether the rest duration between sets of SS decreases the shear elastic modulus. Design: A randomized, repeated-measures experimental design. Setting: University laboratory. Participants: Sixteen healthy males volunteered to participate in the study (age 21.3 [0.8] y; height 171.8 [5.1] cm; weight 63.1 [4.5] kg). Main Outcome Measures: Each participant underwent 3 different rest interval durations during SS (ie, long rest duration: 90 s; normal rest duration: 30 s; and short rest duration: 10 s). This SS technique was repeated 10 times, thus lasting a total of 300 seconds with different rest durations in each protocol. The dorsiflexion ROM and shear elastic modulus were measured before and after SS. Results: Our results revealed that dorsiflexion ROM and shear elastic modulus were changed after 300-second SS; however, no effects of the rest duration between sets of SS were observed. Conclusions: In terms of decreasing the shear elastic modulus, clinicians and coaches should not focus on the rest duration when SS intervention is performed.

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