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 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 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.
Skip Nav Destination
Article navigation
June 2011
Research Papers
Transversely Isotropic Elasticity Imaging of Cancellous Bone
Spencer W. Shore,
Spencer W. Shore
Department of Mechanical Engineering, Boston University, 110 Cummington Street, Boston
, MA 02215 e-mail:
Search for other works by this author on:
Paul E. Barbone,
Paul E. Barbone
Department of Mechanical Engineering, Boston University, 730 Commonwealth Avenue, Boston
, MA 02446 e-mail:
Search for other works by this author on:
Assad A. Oberai,
Assad A. Oberai
Department of Mechanical, Aerospace, and Nuclear Engineering, Rensselaer Polytechnic Institute, 4013 CII
, 110 8th Street, Troy, NY 12180 e-mail:
Search for other works by this author on:
Elise F. Morgan
Elise F. Morgan
Department of Mechanical Engineering, Boston University, 110 Cummington Street, Boston
, MA 02215 e-mail:
Search for other works by this author on:
Spencer W. Shore
Department of Mechanical Engineering, Boston University, 110 Cummington Street, Boston
, MA 02215 e-mail:
Paul E. Barbone
Department of Mechanical Engineering, Boston University, 730 Commonwealth Avenue, Boston
, MA 02446 e-mail:
Assad A. Oberai
Department of Mechanical, Aerospace, and Nuclear Engineering, Rensselaer Polytechnic Institute, 4013 CII
, 110 8th Street, Troy, NY 12180 e-mail:
Elise F. Morgan
Department of Mechanical Engineering, Boston University, 110 Cummington Street, Boston
, MA 02215 e-mail: J Biomech Eng. Jun 2011, 133(6): 061002 (11 pages)
Published Online: June 16, 2011
Article history
Received:
January 25, 2011
Revised:
May 12, 2011
Online:
June 16, 2011
Published:
June 16, 2011
Citation
Shore, S. W., Barbone, P. E., Oberai, A. A., and Morgan, E. F. (June 16, 2011). "Transversely Isotropic Elasticity Imaging of Cancellous Bone." ASME. J Biomech Eng. June 2011; 133(6): 061002. https://doi.org/10.1115/1.4004231
Download citation file:
Get Email Alerts
Related Articles
Long Durations of Immobilization in the Rat Result in Enhanced Mechanical Properties of the Healing Supraspinatus Tendon Insertion Site
J Biomech Eng (June,2007)
Characterization of Spatially Graded Biomechanical Scaffolds
J Biomech Eng (July,2020)
Quantifying the Anisotropy in Biological Materials
J. Appl. Mech (November,2011)
Related Proceedings Papers
Related Chapters
Introduction and Scope
High Frequency Piezo-Composite Micromachined Ultrasound Transducer Array Technology for Biomedical Imaging
Introduction
Ultrasonic Methods for Measurement of Small Motion and Deformation of Biological Tissues for Assessment of Viscoelasticity
Conclusion
Ultrasonic Methods for Measurement of Small Motion and Deformation of Biological Tissues for Assessment of Viscoelasticity