Cancellous bone as a poroelastic medium: Extracting underlying material properties from improved ultrasonic measurements of frequency dependent attenuation and phase velocity.

2009 ◽  
Vol 125 (4) ◽  
pp. 2641-2641
Author(s):  
James G. Miller ◽  
Christian C. Anderson ◽  
Adam Q. Bauer ◽  
Karen Marutyan ◽  
G. Larry Bretthorst ◽  
...  
Keyword(s):  
Phase Velocity ◽  
Cancellous Bone ◽  
Material Properties ◽  
Poroelastic Medium ◽  
Frequency Dependent ◽  
Ultrasonic Measurements

Comparison of conventional ultrasonic phase velocity and attenuation measurements of cancellous bone to estimates obtained using Bayesian probability theory.

2010 ◽  
Vol 127 (3) ◽  
pp. 2006-2006
Author(s):  
Christian C. Anderson ◽  
Michal Pakula ◽  
Pascal Laugier ◽  
G. Larry Bretthorst ◽  
Mark R. Holland ◽  
...  
Keyword(s):  
Probability Theory ◽  
Phase Velocity ◽  
Cancellous Bone ◽  
Bayesian Probability ◽  
Phase Velocity And Attenuation

Material properties of femoral cancellous bone in axial loading

1980 ◽  
Vol 97 (2) ◽  
pp. 95-102 ◽  
Author(s):  
Antonius Rohlmann ◽  
Hans Zilch ◽  
Georg Bergmann ◽  
Reinhard Kolbel
Keyword(s):  
Cancellous Bone ◽  
Material Properties ◽  
Axial Loading

Coupling Sound Absorbing Materials With an Air Cavity Using Frequency Dependent Bulk Material Properties

2016 ◽  
Author(s):  
Shung H. Sung ◽  
Donald J. Nefske
Keyword(s):  
Finite Element ◽  
Frequency Response ◽  
Material Properties ◽  
Complex Frequency ◽  
Air Cavity ◽  
Frequency Dependent ◽  
Absorbing Materials ◽  
Mode Method ◽  
Modal Solution ◽  
Solution Methodology

This paper presents the acoustic finite element method and the modal solution method for coupling sound absorbing materials with an air cavity to predict the sound pressure frequency response. The sound absorbing materials are represented with complex, frequency-dependent, effective mass-density and bulk-modulus properties obtained from the acoustic impedance of material samples. To couple the sound absorber cavity and air cavity, the boundary conditions at the interface between the cavities requires equality of pressure and equality of acoustic volume flow. Two modal solution methods are developed to compute the frequency response of the coupled system with frequency dependent material properties: the component mode method and the coupled mode method. The finite element and modal solution methodology is developed in a form readily adaptable for implementation in commercially available codes. The accuracy of the modal solution methodology is assessed for modeling a one-dimensional air tube terminated with absorbent material and the seats in an automobile passenger compartment.

scholarly journals Transversely Isotropic Elasticity Imaging of Cancellous Bone

2011 ◽  
Vol 133 (6) ◽  
Author(s):  
Spencer W. Shore ◽  
Paul E. Barbone ◽  
Assad A. Oberai ◽  
Elise F. Morgan
Keyword(s):  
Mechanical Properties ◽  
Inverse Problem ◽  
Cancellous Bone ◽  
Material Properties ◽  
Transversely Isotropic ◽  
Elasticity Imaging ◽  
Elastic Parameters ◽  
Displacement Fields ◽  
Isotropic Materials ◽  
Isotropic Elasticity

To measure spatial variations in mechanical properties of biological materials, prior studies have typically performed mechanical tests on excised specimens of tissue. Less invasive measurements, however, are preferable in many applications, such as patient-specific modeling, disease diagnosis, and tracking of age- or damage-related degradation of mechanical properties. Elasticity imaging (elastography) is a nondestructive imaging method in which the distribution of elastic properties throughout a specimen can be reconstructed from measured strain or displacement fields. To date, most work in elasticity imaging has concerned incompressible, isotropic materials. This study presents an extension of elasticity imaging to three-dimensional, compressible, transversely isotropic materials. The formulation and solution of an inverse problem for an anisotropic tissue subjected to a combination of quasi-static loads is described, and an optimization and regularization strategy that indirectly obtains the solution to the inverse problem is presented. Several applications of transversely isotropic elasticity imaging to cancellous bone from the human vertebra are then considered. The feasibility of using isotropic elasticity imaging to obtain meaningful reconstructions of the distribution of material properties for vertebral cancellous bone from experiment is established. However, using simulation, it is shown that an isotropic reconstruction is not appropriate for anisotropic materials. It is further shown that the transversely isotropic method identifies a solution that predicts the measured displacements, reveals regions of low stiffness, and recovers all five elastic parameters with approximately 10% error. The recovery of a given elastic parameter is found to require the presence of its corresponding strain (e.g., a deformation that generates ɛ12 is necessary to reconstruct C1212), and the application of regularization is shown to improve accuracy. Finally, the effects of noise on reconstruction quality is demonstrated and a signal-to-noise ratio (SNR) of 40dB is identified as a reasonable threshold for obtaining accurate reconstructions from experimental data. This study demonstrates that given an appropriate set of displacement fields, level of regularization, and signal strength, the transversely isotropic method can recover the relative magnitudes of all five elastic parameters without an independent measurement of stress. The quality of the reconstructions improves with increasing contrast, magnitude of deformation, and asymmetry in the distributions of material properties, indicating that elasticity imaging of cancellous bone could be a useful tool in laboratory studies to monitor the progression of damage and disease in this tissue.

scholarly journals Combined spatiotemporal and frequency-dependent shear wave elastography enables detection of vulnerable carotid plaques as validated by MRI

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
David Marlevi ◽  
Sharon L. Mulvagh ◽  
Runqing Huang ◽  
J. Kevin DeMarco ◽  
Hideki Ota ◽  
...  
Keyword(s):  
Phase Velocity ◽  
Group Velocity ◽  
Shear Wave ◽  
Shear Wave Elastography ◽  
Intraplaque Hemorrhage ◽  
Frequency Dependent ◽  
Invasive Approach ◽  
Carotid Plaques ◽  
Phase Velocities ◽  
Luminal Narrowing

AbstractFatal cerebrovascular events are often caused by rupture of atherosclerotic plaques. However, rupture-prone plaques are often distinguished by their internal composition rather than degree of luminal narrowing, and conventional imaging techniques might thus fail to detect such culprit lesions. In this feasibility study, we investigate the potential of ultrasound shear wave elastography (SWE) to detect vulnerable carotid plaques, evaluating group velocity and frequency-dependent phase velocities as novel biomarkers for plaque vulnerability. In total, 27 carotid plaques from 20 patients were scanned by ultrasound SWE and magnetic resonance imaging (MRI). SWE output was quantified as group velocity and frequency-dependent phase velocities, respectively, with results correlated to intraplaque constituents identified by MRI. Overall, vulnerable lesions graded as American Heart Association (AHA) type VI showed significantly higher group and phase velocity compared to any other AHA type. A selection of correlations with intraplaque components could also be identified with group and phase velocity (lipid-rich necrotic core content, fibrous cap structure, intraplaque hemorrhage), complementing the clinical lesion classification. In conclusion, we demonstrate the ability to detect vulnerable carotid plaques using combined SWE, with group velocity and frequency-dependent phase velocity providing potentially complementary information on plaque characteristics. With such, the method represents a promising non-invasive approach for refined atherosclerotic risk prediction.

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