scholarly journals In vivo assessment of spinal cord elasticity using shear wave ultrasound in dogs

2018 ◽  
Vol 29 (4) ◽  
pp. 461-469 ◽  
Author(s):  
Amro Al-Habib ◽  
Abdulrahman Albakr ◽  
Abdullah Al Towim ◽  
Metab Alkubeyyer ◽  
Abdullah Abu Jamea ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Shear Wave ◽  
Dura Mater ◽  
Ex Vivo ◽  
Shear Wave Elastography ◽  
Biomechanical Properties ◽  
Tissue Elasticity ◽  
Pia Mater ◽  
Balloon Compression

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.

Effects of compressive lesions on intraoperative human spinal cord elasticity

2021 ◽  
pp. 1-10
Author(s):  
Amro Al-Habib ◽  
Wajda Alhothali ◽  
Abdulrahman Albakr ◽  
Sherif Elwatidy ◽  
Ghaida Alawaji ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Dura Mater ◽  
Shear Wave Elastography ◽  
Conus Medullaris ◽  
Tissue Elasticity ◽  
External Compression ◽  
Human Spinal Cord ◽  
Bone Removal ◽  
The Impact

OBJECTIVE Although evaluating tissue elasticity has various clinical applications, spinal cord elasticity (SCE) in humans has never been well documented. In this study, the authors aimed to evaluate the impact of compression on human SCE in vivo. METHODS The authors prospectively assessed SCE using intraoperative shear wave elastography (SWE). All consecutive patients undergoing spinal cord (SC) decompression (laminectomy or corpectomy) between June 2018 and June 2019 were included. After intraoperative exposure of the patient’s dura mater, at least three SWE measurements of the SC and its coverings were performed. Intraoperative neurological monitoring in the form of motor and somatosensory evoked potentials was utilized. Cases were divided into two groups based on the state of SC compression following bone removal (laminectomy or corpectomy): patients with adequate decompression (the decompressed SC group [DCG]) following bone removal and patients with remining compression, e.g., compressing tumor or instability (the compressed SC group [COG]). RESULTS A total of 25 patients were included (8 females and 17 males) with a mean age of 48.28 ± 21.47 years. Most cases were degenerative diseases (10 cases) followed by tumors (6 cases), and the compression was observed at cervical (n = 14), thoracic (n = 9), and conus medullaris (n = 2) levels. The COG (6 cases) expressed significantly higher elasticity values, i.e., greater stiffness (median 93.84, IQR 75.27–121.75 kPa) than the decompressed SC in DCG (median 9.35, IQR 6.95–11.22 kPa, p < 0.001). Similarly, the compressed dura mater in the COG was significantly stiffer (mean ± SD 121.83 ± 70.63 kPa) than that in the DCG (29.78 ± 18.31 kPa, p = 0.042). Following SC decompression in COG, SCE values were significantly reduced (p = 0.006; adjusted for multiple comparisons). Intraoperative monitoring demonstrated no worsening from the baseline. CONCLUSIONS The current study is to the authors’ knowledge the first to quantitatively demonstrate increased stiffness (i.e., elasticity value) of the human SC and dura mater in response to external compression in vivo. It appears that SCE is a dynamic phenomenon and is reduced following decompression. Moreover, the evaluation of human SCE using the SWE technique is feasible and safe. Information from future studies aiming to further define SCE could be valuable in the early and accurate diagnosis of the compressed SC.

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

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.

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

2013 ◽  
Vol 42 (8) ◽  
pp. 1143-1150 ◽  
Author(s):  
Sébastien Aubry ◽  
Jean-Romain Risson ◽  
Adrian Kastler ◽  
Benoit Barbier-Brion ◽  
Gaye Siliman ◽  
...  
Keyword(s):  
Shear Wave ◽  
Shear Wave Elastography ◽  
Biomechanical Properties ◽  
Calcaneal Tendon

scholarly journals EVALUATION OF IRIDOCILIARY AND LENTICULAR ELASTICITY USING SHEAR-WAVE ELASTOGRAPHY IN RABBIT EYES

2014 ◽  
Vol 57 (1) ◽  
pp. 9-14 ◽  
Author(s):  
Efstathios T. Detorakis ◽  
Eleni E. Drakonaki ◽  
Harilaos Ginis ◽  
Nikolaos Karyotakis ◽  
Ioannis G. Pallikaris
Keyword(s):  
Shear Wave ◽  
Ciliary Body ◽  
Ex Vivo ◽  
Anterior Segment ◽  
Anterior Chamber Depth ◽  
Shear Wave Elastography ◽  
Ultrasound Elastography ◽  
Eye Model ◽  
Rabbit Eye

Introduction: A previous study has employed shear-wave ultrasound elastographic imaging to assess corneal rigidity in an ex-vivo porcine eye model. This study employs the same modality in vivo in a rabbit eye model in order to assess lens, ciliary body and total ocular rigidity changes following the instillation of atropine and pilocarpine. Methods: Ten non-pigmented female rabbits were examined. Measurements of the lens, ciliary body and total ocular rigidity as well as lens thickness and anterior chamber depth were taken with the Aixplorer system (SuperSonic Imagine, Aix-en-Provence, France) with the SuperLinear™ SL 15-4 transducer in both eyes at baseline as well as after pilocarpine and atropine instillation. The IOP was also measured with the TonoPen tonometer. Results: Changes in rigidity in the examined areas following atropine instillation were statistically not significant. Ciliary body rigidity was significantly increased whereas lens and total ocular rigidity were significantly reduced following pilocarpine instillation. The decrease in lens rigidity following pilocarpine was significantly associated with the respective increase in ciliary body rigidity. Conclusions: Shear-wave ultrasound elastography can detect in vivo rigidity changes in the anterior segment of the rabbit eye model and may potentially be applied in human eyes, providing useful clinical information on conditions in which rigidity changes play an important role, such as glaucoma, pseudoexfoliation syndrome or presbyopia.

Characterization of Passive Elastic Properties of the Human Tibialis Anterior Muscle Using Supersonic Shear Wave Elastography

2013 ◽  
Author(s):  
Terry K. Koo ◽  
Jingyi Guo ◽  
Jeffrey H. Cohen ◽  
Kevin J. Parker
Keyword(s):  
Shear Wave ◽  
Elastic Properties ◽  
Tibialis Anterior ◽  
Ex Vivo ◽  
Tibialis Anterior Muscle ◽  
Shear Wave Elastography ◽  
Indirect Measurement ◽  
Muscle Elasticity ◽  
Passive Muscle

In a companion ex vivo study of chicken muscles [1], we demonstrated that muscle elasticity measured by Supersonic shear wave elastography (SWE) increases linearly with passive tension, and hence, SWE could be an indirect measurement of passive muscle force. Objectives of the present study were: (1) Determine the test-retest reliability of SWE for in vivo measurements of passive muscle elasticity of the tibialis anterior (TA) muscle; (2) Assess the relationship between elasticity and ankle angle of the TA; and (3) Extract physiologically meaningful parameters from the elasticity-angle curves for better quantification of passive elastic properties.

Evaluation of the Effect of Tissue Compression on the Results of Shear Wave Elastography Measurements

2018 ◽  
Vol 40 (6) ◽  
pp. 380-393 ◽  
Author(s):  
Jaromir Vachutka ◽  
Zuzana Sedlackova ◽  
Tomas Furst ◽  
Miroslav Herman ◽  
Jan Herman ◽  
...  
Keyword(s):  
Young’S Modulus ◽  
Shear Wave ◽  
Ex Vivo ◽  
Young's Modulus ◽  
Shear Wave Elastography ◽  
Shear Wave Imaging ◽  
Phantom Measurements ◽  
Wave Imaging ◽  
Tissue Compression

Shear wave imaging is considered to be more precise and less operator dependent when compared with strain imaging. It enables quantitative and reproducible data (Young’s modulus of the imaged tissue). However, results of shear wave imaging can be affected by a variety of different factors. The aim of this study is to evaluate the effect of the pressure applied by the ultrasound probe during examination on the measured values of Young’s modulus. The effect of the tissue compression on the results of the real-time shear wave elastography was evaluated via the gelatine phantom measurements, via the ex vivo experiments with pig liver, and via the in vivo measurements of the thyroid gland stiffness on healthy volunteers. The results of our measurements confirmed that the measured value of Young’s modulus increases with the increasing pressure applied on the imaged object. The highest increase was observed during the ex vivo experiments (400%), and the lowest increase was detected in the case of the phantom measurements (8%). A two- to threefold increase in Young’s modulus was observed between the minimum and maximum pressure in the case of the in vivo elastography measurements of thyroid gland. The Veronda-Westman theoretical model was used for the description of the tissue nonlinearity. We conclude that tissue compression by the force exerted on the probe can significantly affect the results of the real-time shear wave elastography measurements. Minimum pressure should be used when measuring the absolute value of Young’s modulus of superficial organs.

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