Effect of renal perfusion and structural heterogeneity on shear wave elastography of the kidney: an in vivo and ex vivo study

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.

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Shear Wave Elastography Can Differentiate between Radiation-Responsive and Non-responsive Pancreatic Tumors: An ex Vivo Study with Murine Models

Ultrasound in Medicine & Biology ◽

10.1016/j.ultrasmedbio.2019.10.005 ◽

2020 ◽

Vol 46 (2) ◽

pp. 393-404

Author(s):

Hexuan Wang ◽

Bradley Mills ◽

Reem Mislati ◽

Rifat Ahmed ◽

Scott A. Gerber ◽

...

Keyword(s):

Shear Wave ◽

Ex Vivo ◽

Shear Wave Elastography ◽

Pancreatic Tumors ◽

Murine Models ◽

Ex Vivo Study

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

Journal of Neurosurgery Spine ◽

10.3171/2018.2.spine171195 ◽

2018 ◽

Vol 29 (4) ◽

pp. 461-469 ◽

Cited By ~ 2

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.

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

Volume 1B: Extremity; Fluid Mechanics; Gait; Growth, Remodeling, and Repair; Heart Valves; Injury Biomechanics; Mechanotransduction and Sub-Cellular Biophysics; MultiScale Biotransport; Muscle, Tendon and Ligament; Musculoskeletal Devices; Multiscale Mechanics; Thermal Medicine; Ocular Biomechanics; Pediatric Hemodynamics; Pericellular Phenomena; Tissue Mechanics; Biotransport Design and Devices; Spine; Stent Device Hemodynamics; Vascular Solid Mechanics; Student Paper and Design Competitions ◽

10.1115/sbc2013-14284 ◽

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.

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

Ultrasonic Imaging ◽

10.1177/0161734618793837 ◽

2018 ◽

Vol 40 (6) ◽

pp. 380-393 ◽

Cited By ~ 5

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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64Cu-ATSM/64Cu-Cl2 and their relationship to hypoxia in glioblastoma: a preclinical study

EJNMMI Research ◽

10.1186/s13550-019-0586-6 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 4

Author(s):

Elodie A. Pérès ◽

Jérôme Toutain ◽

Louis-Paul Paty ◽

Didier Divoux ◽

Méziane Ibazizène ◽

...

Keyword(s):

Ex Vivo ◽

In Vitro Study ◽

Tumor Location ◽

Preclinical Study ◽

Significant Rise ◽

Lower Oxygen ◽

Cu Complexes ◽

Ex Vivo Study

Abstract Background Diacetyl-bis(N4-methylthiosemicarbazone), labeled with 64Cu (64Cu-ATSM) has been suggested as a promising tracer for imaging hypoxia. However, various controversial studies highlighted potential pitfalls that may disable its use as a selective hypoxic marker. They also highlighted that the results may be tumor location dependent. Here, we first analyzed uptake of Cu-ATSM and its less lipophilic counterpart Cu-Cl2 in the tumor over time in an orthotopic glioblastoma model. An in vitro study was also conducted to investigate the hypoxia-dependent copper uptake in tumor cells. We then further performed a comprehensive ex vivo study to compare 64Cu uptake to hypoxic markers, specific cellular reactions, and also transporter expression. Methods μPET was performed 14 days (18F-FMISO), 15 days (64Cu-ATSM and 64Cu-Cl2), and 16 days (64Cu-ATSM and 64Cu-Cl2) after C6 cell inoculation. Thereafter, the brains were withdrawn for further autoradiography and immunohistochemistry. C6 cells were also grown in hypoxic workstation to analyze cellular uptake of Cu complexes in different oxygen levels. Results In vivo results showed that Cu-ASTM and Cu-Cl2 accumulated in hypoxic areas of the tumors. Cu-ATSM also stained, to a lesser extent, non-hypoxic regions, such as regions of astrogliosis, with high expression of copper transporters and in particular DMT-1 and CTR1, and also characterized by the expression of elevated astrogliosis. In vitro results show that 64Cu-ATSM showed an increase in the uptake only in severe hypoxia at 0.5 and 0.2% of oxygen while for 64Cu-Cl2, the cell retention was significantly increased at 5% and 1% of oxygen with no significant rise at lower oxygen percentages. Conclusion In the present study, we show that Cu-complexes undoubtedly accumulate in hypoxic areas of the tumors. This uptake may be the reflection of a direct dependency to a redox metabolism and also a reflection of hypoxic-induced overexpression of transporters. We also show that Cu-ATSM also stained non-hypoxic regions such as astrogliosis.

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Insight into Glutamatergic Involvement in Rewarding Effects of Mephedrone in Rats: In Vivo and Ex Vivo Study

Molecular Neurobiology ◽

10.1007/s12035-021-02404-y ◽

2021 ◽

Author(s):

Olga Wronikowska ◽

Maria Zykubek ◽

Agnieszka Michalak ◽

Anna Pankowska ◽

Paulina Kozioł ◽

...

Keyword(s):

Ex Vivo ◽

Interdisciplinary Approach ◽

Nmda Antagonist ◽

Exchange Chromatography ◽

Resonance Spectroscopy ◽

Monoamine Transporters ◽

Ex Vivo Study ◽

Insight Into

AbstractMephedrone is a widely used drug of abuse, exerting its effects by interacting with monoamine transporters. Although this mechanism has been widely studied heretofore, little is known about the involvement of glutamatergic transmission in mephedrone effects. In this study, we comprehensively evaluated glutamatergic involvement in rewarding effects of mephedrone using an interdisciplinary approach including (1) behavioural study on effects of memantine (non-selective NMDA antagonist) on expression of mephedrone-induced conditioned place preference (CPP) in rats; (2) evaluation of glutamate concentrations in the hippocampus of rats following 6 days of mephedrone administration, using in vivo magnetic resonance spectroscopy (MRS); and (3) determination of glutamate levels in the hippocampus of rats treated with mephedrone and subjected to MRS, using ion-exchange chromatography. In the presented research, we confirmed priorly reported mephedrone-induced rewarding effects in the CPP paradigm and showed that memantine (5 mg/kg) was able to reverse the expression of this effect. MRS study showed that subchronic mephedrone administration increased glutamate level in the hippocampus when measured in vivo 24 h (5 mg/kg, 10 mg/kg and 20 mg/kg) and 2 weeks (5 mg/kg and 20 mg/kg) after last injection. Ex vivo chromatographic analysis did not show significant changes in hippocampal glutamate concentrations; however, it showed similar results as obtained in the MRS study proving its validity. Taken together, the presented study provides new insight into glutamatergic involvement in rewarding properties of mephedrone.

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