In Vivo Imaging of Dynamic Shear Modulus of Rodent Mammary Tumors Using Ultrasound

2012 ◽  
Author(s):  
Yue Wang ◽  
Michael Insana
Keyword(s):  
In Vivo Imaging ◽  
Normal Tissue ◽  
Breast Tissue ◽  
Structural Integrity ◽  
Biomechanical Properties ◽  
Dynamic Shear Modulus ◽  
Living Tissue ◽  
Dynamic Shear

Biomechanical properties of living tissue are very important in maintaining normal tissue function, cellular and extracellular structural integrity. Therefore, the quantitative determination of biomechanical properties of breast tissue, especially in vivo, serves an important role in clinical diagnosis.

Altered biomechanical properties of carotid arteries in two mouse models of muscular dystrophy

2007 ◽  
Vol 103 (2) ◽  
pp. 664-672 ◽  
Author(s):  
W. W. Dye ◽  
R. L. Gleason ◽  
E. Wilson ◽  
J. D. Humphrey
Keyword(s):  
Muscular Dystrophy ◽  
Axial Force ◽  
Carotid Arteries ◽  
Structural Integrity ◽  
Muscle Cells ◽  
Biomechanical Properties ◽  
Axial Stiffness ◽  
Wild Type ◽  
Functional Responses

Muscular dystrophy is characterized by skeletal muscle weakness and wasting, but little is known about possible alterations to the vasculature. Many muscular dystrophies are caused by a defective dystrophin-glycoprotein complex (DGC), which plays an important role in mechanotransduction and maintenance of structural integrity in muscle cells. The DGC is a group of membrane-associated proteins, including dystrophin and sarcoglycan-δ, that helps connect the cytoskeleton of muscle cells to the extracellular matrix. In this paper, mice lacking genes encoding dystrophin ( mdx) or sarcoglycan-δ ( sgcd−/−) were studied to detect possible alterations to vascular wall mechanics. Pressure-diameter and axial force-length tests were performed on common carotid arteries from mdx, sgcd−/−, and wild-type mice in active (basal) and passive smooth muscle states, and functional responses to three vasoactive compounds were determined at constant pressure and length. Apparent biomechanical differences included the following: mdx and sgcd−/− arteries had decreased distensibilities in pressure-diameter tests, with mdx arteries exhibiting elevated circumferential stresses, and mdx and sgcd−/− arteries generated elevated axial loads and stresses in axial force-length tests. Interestingly, however, mdx and sgcd−/− arteries also had significantly lower in vivo axial stretches than did the wild type. Accounting for this possible adaptation largely eliminated the apparent differences in circumferential and axial stiffness, thus suggesting that loss of DGC proteins may induce adaptive biomechanical changes that can maintain overall wall mechanics in response to normal loads. Nevertheless, there remains a need to understand better possible vascular adaptations in response to sustained altered loads in patients with muscular dystrophy.

Determination of the Dynamic Shear Modulus of a Composite Solid Propellant

1963 ◽  
Vol 34 (12) ◽  
pp. 1333-1340 ◽  
Author(s):  
Lionel H. Layton ◽  
G. A. Sheppard ◽  
S. John Bennett
Keyword(s):  
Shear Modulus ◽  
Solid Propellant ◽  
Dynamic Shear Modulus ◽  
Dynamic Shear ◽  
Composite Solid Propellant ◽  
Composite Solid

Determination of the dynamic shear modulus and loss factor of rubber

1980 ◽  
Vol 67 (S1) ◽  
pp. S24-S24
Author(s):  
G. Gaunaurd ◽  
K. P. Scharnhorst ◽  
H. Überall
Keyword(s):  
Shear Modulus ◽  
Loss Factor ◽  
Dynamic Shear Modulus ◽  
Dynamic Shear

In Vivo Imaging of Pressure Effects in Normal Breast Tissue with Quantitative Multi-Spectral Near-Infrared Tomography

2004 ◽  
Author(s):  
Shudong Jiang ◽  
Brian W. Pogue ◽  
Xiaomei Song ◽  
Subhadra Srinivasan ◽  
Keith D. Paulsen ◽  
...  
Keyword(s):  
In Vivo Imaging ◽  
Breast Tissue ◽  
Near Infrared ◽  
Normal Breast Tissue ◽  
Normal Breast ◽  
Pressure Effects ◽  
Infrared Tomography

scholarly journals Measurement of the Dynamic Shear Modulus of Mouse Brain Tissue In Vivo by Magnetic Resonance Elastography

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
Stefan M. Atay ◽  
Christopher D. Kroenke ◽  
Arash Sabet ◽  
Philip V. Bayly
Keyword(s):  
Magnetic Resonance ◽  
Shear Modulus ◽  
Brain Tissue ◽  
Mouse Brain ◽  
Ex Vivo ◽  
Three Dimensions ◽  
Dynamic Shear Modulus ◽  
Dynamic Shear ◽  
High Deformation

In this study, the magnetic resonance (MR) elastography technique was used to estimate the dynamic shear modulus of mouse brain tissue in vivo. The technique allows visualization and measurement of mechanical shear waves excited by lateral vibration of the skull. Quantitative measurements of displacement in three dimensions during vibration at 1200Hz were obtained by applying oscillatory magnetic field gradients at the same frequency during a MR imaging sequence. Contrast in the resulting phase images of the mouse brain is proportional to displacement. To obtain estimates of shear modulus, measured displacement fields were fitted to the shear wave equation. Validation of the procedure was performed on gel characterized by independent rheometry tests and on data from finite element simulations. Brain tissue is, in reality, viscoelastic and nonlinear. The current estimates of dynamic shear modulus are strictly relevant only to small oscillations at a specific frequency, but these estimates may be obtained at high frequencies (and thus high deformation rates), noninvasively throughout the brain. These data complement measurements of nonlinear viscoelastic properties obtained by others at slower rates, either ex vivo or invasively.

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